Clinical Review

Division of Infectious Diseases, Department of Internal Medicine, VA Ann Arbor Healthcare System and University of Michigan Health System, Ann Arbor, MI.

Abstract

• Objective: To review prevention of central line–associated bloodstream infection (CLABSI).
• Method: Review of the literature.
• Results: Evidence-based prevention practices include ensuring hand hygiene before the procedure, using maximal sterile barrier precautions, cleaning the skin with alcoholic chlorhexidine before central line insertion, avoiding the femoral site for insertion, and removing unneeded catheters.
• Conclusion: For continued success in CLABSI prevention, best practices should be followed and patient safety should be emphasized.

Health care–associated infections (HAIs) are a preventable cause of morbidity and mortality in the United States and internationally. A Centers for Disease Control and Prevention (CDC) report estimates that in acute care hospitals, 1 in 25 patients end up with at least one HAI during their hospital stay [1]. HAIs can also be costly; in the United States, the indirect and direct cost has been estimated to be between $96 to $147 billion dollars [2]. National initiatives to prevent these types of infections have included efforts from the Department of Health and Human Services (HHS), the Institute of Medicine (IOM), the Institute for Healthcare Improvement (IHI) and the Centers for Medicare and Medicaid Services (CMS). This work has led to particular success in preventing central line–associated bloodstream infection (CLABSI).

CLABSI can lead to considerable mortality, morbidity, and cost. An estimated 250,000 CLABSIs occur in patients yearly, and about 80,000 of those are estimated to occur in the intensive care unit (ICU) setting [3]. Since central venous catheters (CVCs), or central lines, are most often used in the ICU setting, much of the work on prevention and management of CLABSI has been within the ICU population [4,5]. The increased use of peripherally inserted central catheters (PICCs) in the non-ICU setting and recognition of CLABSI in non-ICU settings has led to new efforts to understand the best way to prevent CLABSI in the non-ICU setting [4,6]. Regardless of setting, the annual cost of these infections has been estimated to be as high as $2.3 billion [7]. One episode is estimated to cost a hospital up to $46,485 per episode with components of excess length of stay, antibiotic cost, and cost of care [8]. In this review, selected best practices in CLABSI prevention are identified and described.

Elements of CLABSI Prevention

One of the key papers in the CLABSI literature was the Keystone ICU project in Michigan [9]. This state-wide effort grew out of a successful pilot patient-safety program that was trialed at Johns Hopkins Medical Institutions to reduce CLABSI in the ICU setting. In 2003, the Agency for Healthcare Research and Quality (AHRQ) funded a study to examine the intervention in ICUs in the state of Michigan. A total of 108 ICUs from 67 individual hospitals participated in the pre-intervention/post-intervention study [9]. A combination of technical and socio-adaptive interventions to prevent CLABSI included clinician education on best practices in insertion of central lines, having a central-line cart in each ICU, an insertion checklist of best practices, empowering nursing staff to stop the procedure if best practices were not being followed, discussing removal of catheters daily, and providing feedback to units regarding rates of CLABSI [10]. Executive administration of each hospital was also involved and there were monthly phone calls for hospital teams to share successes and barriers.

In the pre-intervention phase, the median catheter- related bloodstream infection rate was 2.7 infections per 1000 catheter days for the sum of hospitals. After the interventions were put in place, the median rate of catheter related bloodstream infections was down to 0.34 at 18 months. The study showed that results from a relatively inexpensive and straightforward intervention could be effective and could last in the long term. This study led to many other single center and multicenter studies, nationally and internationally, to replicate results in efforts to decrease CLABSI in ICU populations [5]. The CDC and AHRQ have continued to partner with regional, state and national efforts to focus on CLABSI prevention.

The Bundle Approach

A number of interventions have been proven to be effective at preventing CLABSI. Combining more than one intervention can often have additive effects. This effect has been recognized in numerous quality improvement studies on CLABSI and has been termed using the “bundle” approach. 

Hand Hygiene

Poor hand hygiene by health care workers is generally thought to be the most common cause of HAIs [12]. Guidelines recommend an alcohol-based waterless product or antiseptic soap and water prior to catheter insertion [13]. The most common underlying etiology of CLABSI is through microorganisms introduced at time of insertion of catheter. This can be extraluminally mediated via skin flora of the patient, or due to lack of hand washing on the inserter’s part and can lead to CLABSI [14]. While a randomized controlled trial would be unethical, several studies have shown when targeted hand hygiene campaigns are held, CLABSI rates tend to decrease [15–17].

Maximal Barrier Precautions

The use of maximal sterile barrier precautions has been associated with less mortality, decreasing catheter colonization, incidence of HAI and cost savings [18–20]. Like most components of the bundle, maximal sterile barrier precautions have rarely been studied alone, but are often a part of a “bundle” or number of interventions [21]. Like hand hygiene, while regularly a part of many hospital’s checklist or bundle process, compliance with this key part of infection prevention can be deficient; one study noted measured maximal sterile barriers compliance to be 44% [22].

Chlorhexidine Skin Antisepsis

Chlorhexidine skin preparation decreases bacterial burden at site of insertion and is thought to reduce infection from this mechanism. Chlorhexidine-alcohol skin preparation has been proven in randomized controlled trials to outperform povidone iodine-alcohol in preventing CLABSI [23,24]. Chlorhexidine skin preparation is considered a technical element of checklists and is thought to be a straightforward and easily implementable action [25]. If a hospital supplies only alcoholic chlorhexidine and doesn’t provide povidone-iodine for skin preparation, then clinicians can be “nudged” towards performing this part of the bundle.

Optimal Catheter Site Selection

For all sites of insertion of CVC, the risk of mechanical and infectious complications depends on the skill and proficiency of operators, the clinical situation, and the availability of ultrasound to help guide placement. These factors are important in determining which anatomical site is best for each patient [26]. The femoral site has been associated with a greater risk of catheter-related infection and catheter-related thrombosis and is not recommended as the initial choice for non-emergent CVC insertion according to national guidelines [13,27]. The internal jugular vein site is associated with a lower risk of severe mechanical complications such as pneumothorax when compared to subclavian vein site [27]. The subclavian vein site is associated with a lower risk of catheter-related blood stream infection and lower rate of thrombosis, but this greatly depends on experience of operator. Experts have proposed that the subclavian site has a lower burden of colonization by bacteria than other sites and is anatomically more protected by catheter dressing; also the subcutaneous course of the central line itself is longer for the subclavian site than other sites and these reasons could contribute to the lower risk of infection [28]. The subclavian site is, however, associated with a higher risk of mechanical complications that can be serious for ICU patients. In general, the femoral vein site should be avoided in non-emergent line placement situations, particularly if the patient is an obese adult [13]. Using ultrasound as a guidance for catheter insertion has also been shown to reduce risk of CLABSI and other mechanical complications and is recommended [29,30].

Daily Review of Line Necessity

Removing unnecessary catheters as soon as possible decreases catheter dwell time and risk of infection. Few studies have concentrated on this step alone in CLABSI prevention, but the studies that have focused on catheter removal usually implement electronic reminders or multidisciplinary catheter rounds (where need for catheter is incorporated into daily rounds or discussed separately by a multidisciplinary group) [5,31].

Additional Considerations

Other basic practices that all hospitals should adopt include the above strategies and providing all inclusive catheter carts or kits, disinfecting hubs in maintenance care of catheters, covering the CVC site with sterile dressings, having recurrent educational interventions and using checklists to assure adherence to the evidence-based bundle (Table) [4,13]. As prevalence of non-ICU central lines has also grown, maintenance care is particularly important in reducing CLABSI. Maintenance bundles that highlight best practices such as aseptic technique, correct hand hygiene, chlorhexidine skin disinfection scrub, antimicrobial bandage application, and catheter hub disinfection have been used with success [32]. Specialized CVC insertion teams with trained personnel have also been recommended [4]. When these basic evidence-based practices are still unable to bring down CLABSI rates for select populations or during an outbreak, supplemental strategies can be tried to reduce CLABSI. These include antimicrobial-impregnated catheters, chlorhexidine-impregnated dressings, and chlorhexidine bathing, which is increasingly being used in the ICU setting [5,13,33].

Epidemiology/Risk Factors

At-risk Populations

ICU patients are at risk for CLABSI because of frequent use of multiple catheters, and the comorbidities and acuity of care that these patients have. ICU patients also tend to have lots of manipulation of their catheters and often these catheters are placed in emergent situations [13]. Patients in the non-ICU and outpatient setting are also at risk for CLABSI when they have a central venous catheter. Long courses of antibiotics for disease states such as osteomyelitis and endocarditis often entail central venous catheters. Recent work has shown that PICCs carry as high of a CLABSI risk as short-term CVCs in hospitalized patients [34]. Patients with end-stage renal disease, especially those undergoing maintenance hemodialysis via a tunneled dialysis catheter are particularly vulnerable to CLABSI [13,35].

Risk Factors for CLABSI

A number of studies have reviewed risk factors and epidemiology of CLABSI in the adult and pediatric population. Factors that have been associated with risk of CLABSI in more than one study include prolonged hospitalization before placement of the central line, prolonged duration of the central line, heavy microbial colonization at the site of insertion, heavy microbial colonization of the catheter hub, multiple lumens, internal jugular site catheterization, femoral vein site catheterization, neutropenia of the patient, a reduced nurse to patient ratio in the ICU setting, presence of total parenteral nutrition, and poor maintenance care of the catheter [4,13,36–40]. One study [41] that calculated a score to help predict risk of PICC-CLABSI found that previous CLABSI (within 3 months of PICC insertion) significantly increases risk of repeat CLABSI.

Conclusion

CLABSI is an important cause of morbidity, mortality and cost. There has been remarkable success in prevention of these infections in recent years due to focused efforts on patient safety. As efforts have multiplied to put into place interventions to decrease CLABSI nationally, the CDC published a Vital Signs report discussing the impact of these efforts [42]. It was estimated that over one decade, infection prevention efforts had avoided 25,000 CLABSIs in U.S. ICUs, a 58% reduction in this infection [42]. CLABSI has served as the best example of using evidence-based interventions through an infection prevention bundle or framework to reduce HAIs. Similar approaches are being used to try to reduce catheter-associated urinary tract infection, Clostridium difficile infection, surgical site infection, and ventilator-associated pneumonia, but there have been less distinct successes nationally and internationally for these other HAIs.

The literature emphasizes that there are several evidence-based measures that can prevent CLABSI. These include hand hygiene, using alcoholic chlorhexidine for skin preparation prior to insertion, maximal sterile barrier precautions, avoiding the femoral site for CVC insertion, and removing unnecessary catheters as soon as possible. Support from administration in emphasizing patient safety and HAI prevention along with following evidence-based practice could lead to long-term improvement in CLABSI prevention across hospital systems.

Corresponding author: Payal K. Patel, MD, MPH, Div of Infectious Diseases, Dept of Internal Medicine, VA Ann Arbor Healthcare System, 2215 Fuller Rd, Ann Arbor, MI 48105, [email protected].

Financial disclosures: None.

Division of Infectious Diseases, Department of Internal Medicine, VA Ann Arbor Healthcare System and University of Michigan Health System, Ann Arbor, MI.

Abstract

• Objective: To review prevention of central line–associated bloodstream infection (CLABSI).
• Method: Review of the literature.
• Results: Evidence-based prevention practices include ensuring hand hygiene before the procedure, using maximal sterile barrier precautions, cleaning the skin with alcoholic chlorhexidine before central line insertion, avoiding the femoral site for insertion, and removing unneeded catheters.
• Conclusion: For continued success in CLABSI prevention, best practices should be followed and patient safety should be emphasized.

Health care–associated infections (HAIs) are a preventable cause of morbidity and mortality in the United States and internationally. A Centers for Disease Control and Prevention (CDC) report estimates that in acute care hospitals, 1 in 25 patients end up with at least one HAI during their hospital stay [1]. HAIs can also be costly; in the United States, the indirect and direct cost has been estimated to be between $96 to $147 billion dollars [2]. National initiatives to prevent these types of infections have included efforts from the Department of Health and Human Services (HHS), the Institute of Medicine (IOM), the Institute for Healthcare Improvement (IHI) and the Centers for Medicare and Medicaid Services (CMS). This work has led to particular success in preventing central line–associated bloodstream infection (CLABSI).

CLABSI can lead to considerable mortality, morbidity, and cost. An estimated 250,000 CLABSIs occur in patients yearly, and about 80,000 of those are estimated to occur in the intensive care unit (ICU) setting [3]. Since central venous catheters (CVCs), or central lines, are most often used in the ICU setting, much of the work on prevention and management of CLABSI has been within the ICU population [4,5]. The increased use of peripherally inserted central catheters (PICCs) in the non-ICU setting and recognition of CLABSI in non-ICU settings has led to new efforts to understand the best way to prevent CLABSI in the non-ICU setting [4,6]. Regardless of setting, the annual cost of these infections has been estimated to be as high as $2.3 billion [7]. One episode is estimated to cost a hospital up to $46,485 per episode with components of excess length of stay, antibiotic cost, and cost of care [8]. In this review, selected best practices in CLABSI prevention are identified and described.

Elements of CLABSI Prevention

One of the key papers in the CLABSI literature was the Keystone ICU project in Michigan [9]. This state-wide effort grew out of a successful pilot patient-safety program that was trialed at Johns Hopkins Medical Institutions to reduce CLABSI in the ICU setting. In 2003, the Agency for Healthcare Research and Quality (AHRQ) funded a study to examine the intervention in ICUs in the state of Michigan. A total of 108 ICUs from 67 individual hospitals participated in the pre-intervention/post-intervention study [9]. A combination of technical and socio-adaptive interventions to prevent CLABSI included clinician education on best practices in insertion of central lines, having a central-line cart in each ICU, an insertion checklist of best practices, empowering nursing staff to stop the procedure if best practices were not being followed, discussing removal of catheters daily, and providing feedback to units regarding rates of CLABSI [10]. Executive administration of each hospital was also involved and there were monthly phone calls for hospital teams to share successes and barriers.

In the pre-intervention phase, the median catheter- related bloodstream infection rate was 2.7 infections per 1000 catheter days for the sum of hospitals. After the interventions were put in place, the median rate of catheter related bloodstream infections was down to 0.34 at 18 months. The study showed that results from a relatively inexpensive and straightforward intervention could be effective and could last in the long term. This study led to many other single center and multicenter studies, nationally and internationally, to replicate results in efforts to decrease CLABSI in ICU populations [5]. The CDC and AHRQ have continued to partner with regional, state and national efforts to focus on CLABSI prevention.

The Bundle Approach

A number of interventions have been proven to be effective at preventing CLABSI. Combining more than one intervention can often have additive effects. This effect has been recognized in numerous quality improvement studies on CLABSI and has been termed using the “bundle” approach. 

Hand Hygiene

Poor hand hygiene by health care workers is generally thought to be the most common cause of HAIs [12]. Guidelines recommend an alcohol-based waterless product or antiseptic soap and water prior to catheter insertion [13]. The most common underlying etiology of CLABSI is through microorganisms introduced at time of insertion of catheter. This can be extraluminally mediated via skin flora of the patient, or due to lack of hand washing on the inserter’s part and can lead to CLABSI [14]. While a randomized controlled trial would be unethical, several studies have shown when targeted hand hygiene campaigns are held, CLABSI rates tend to decrease [15–17].

Maximal Barrier Precautions

The use of maximal sterile barrier precautions has been associated with less mortality, decreasing catheter colonization, incidence of HAI and cost savings [18–20]. Like most components of the bundle, maximal sterile barrier precautions have rarely been studied alone, but are often a part of a “bundle” or number of interventions [21]. Like hand hygiene, while regularly a part of many hospital’s checklist or bundle process, compliance with this key part of infection prevention can be deficient; one study noted measured maximal sterile barriers compliance to be 44% [22].

Chlorhexidine Skin Antisepsis

Chlorhexidine skin preparation decreases bacterial burden at site of insertion and is thought to reduce infection from this mechanism. Chlorhexidine-alcohol skin preparation has been proven in randomized controlled trials to outperform povidone iodine-alcohol in preventing CLABSI [23,24]. Chlorhexidine skin preparation is considered a technical element of checklists and is thought to be a straightforward and easily implementable action [25]. If a hospital supplies only alcoholic chlorhexidine and doesn’t provide povidone-iodine for skin preparation, then clinicians can be “nudged” towards performing this part of the bundle.

Optimal Catheter Site Selection

For all sites of insertion of CVC, the risk of mechanical and infectious complications depends on the skill and proficiency of operators, the clinical situation, and the availability of ultrasound to help guide placement. These factors are important in determining which anatomical site is best for each patient [26]. The femoral site has been associated with a greater risk of catheter-related infection and catheter-related thrombosis and is not recommended as the initial choice for non-emergent CVC insertion according to national guidelines [13,27]. The internal jugular vein site is associated with a lower risk of severe mechanical complications such as pneumothorax when compared to subclavian vein site [27]. The subclavian vein site is associated with a lower risk of catheter-related blood stream infection and lower rate of thrombosis, but this greatly depends on experience of operator. Experts have proposed that the subclavian site has a lower burden of colonization by bacteria than other sites and is anatomically more protected by catheter dressing; also the subcutaneous course of the central line itself is longer for the subclavian site than other sites and these reasons could contribute to the lower risk of infection [28]. The subclavian site is, however, associated with a higher risk of mechanical complications that can be serious for ICU patients. In general, the femoral vein site should be avoided in non-emergent line placement situations, particularly if the patient is an obese adult [13]. Using ultrasound as a guidance for catheter insertion has also been shown to reduce risk of CLABSI and other mechanical complications and is recommended [29,30].

Daily Review of Line Necessity

Removing unnecessary catheters as soon as possible decreases catheter dwell time and risk of infection. Few studies have concentrated on this step alone in CLABSI prevention, but the studies that have focused on catheter removal usually implement electronic reminders or multidisciplinary catheter rounds (where need for catheter is incorporated into daily rounds or discussed separately by a multidisciplinary group) [5,31].

Additional Considerations

Other basic practices that all hospitals should adopt include the above strategies and providing all inclusive catheter carts or kits, disinfecting hubs in maintenance care of catheters, covering the CVC site with sterile dressings, having recurrent educational interventions and using checklists to assure adherence to the evidence-based bundle (Table) [4,13]. As prevalence of non-ICU central lines has also grown, maintenance care is particularly important in reducing CLABSI. Maintenance bundles that highlight best practices such as aseptic technique, correct hand hygiene, chlorhexidine skin disinfection scrub, antimicrobial bandage application, and catheter hub disinfection have been used with success [32]. Specialized CVC insertion teams with trained personnel have also been recommended [4]. When these basic evidence-based practices are still unable to bring down CLABSI rates for select populations or during an outbreak, supplemental strategies can be tried to reduce CLABSI. These include antimicrobial-impregnated catheters, chlorhexidine-impregnated dressings, and chlorhexidine bathing, which is increasingly being used in the ICU setting [5,13,33].

Epidemiology/Risk Factors

At-risk Populations

ICU patients are at risk for CLABSI because of frequent use of multiple catheters, and the comorbidities and acuity of care that these patients have. ICU patients also tend to have lots of manipulation of their catheters and often these catheters are placed in emergent situations [13]. Patients in the non-ICU and outpatient setting are also at risk for CLABSI when they have a central venous catheter. Long courses of antibiotics for disease states such as osteomyelitis and endocarditis often entail central venous catheters. Recent work has shown that PICCs carry as high of a CLABSI risk as short-term CVCs in hospitalized patients [34]. Patients with end-stage renal disease, especially those undergoing maintenance hemodialysis via a tunneled dialysis catheter are particularly vulnerable to CLABSI [13,35].

Risk Factors for CLABSI

A number of studies have reviewed risk factors and epidemiology of CLABSI in the adult and pediatric population. Factors that have been associated with risk of CLABSI in more than one study include prolonged hospitalization before placement of the central line, prolonged duration of the central line, heavy microbial colonization at the site of insertion, heavy microbial colonization of the catheter hub, multiple lumens, internal jugular site catheterization, femoral vein site catheterization, neutropenia of the patient, a reduced nurse to patient ratio in the ICU setting, presence of total parenteral nutrition, and poor maintenance care of the catheter [4,13,36–40]. One study [41] that calculated a score to help predict risk of PICC-CLABSI found that previous CLABSI (within 3 months of PICC insertion) significantly increases risk of repeat CLABSI.

Conclusion

CLABSI is an important cause of morbidity, mortality and cost. There has been remarkable success in prevention of these infections in recent years due to focused efforts on patient safety. As efforts have multiplied to put into place interventions to decrease CLABSI nationally, the CDC published a Vital Signs report discussing the impact of these efforts [42]. It was estimated that over one decade, infection prevention efforts had avoided 25,000 CLABSIs in U.S. ICUs, a 58% reduction in this infection [42]. CLABSI has served as the best example of using evidence-based interventions through an infection prevention bundle or framework to reduce HAIs. Similar approaches are being used to try to reduce catheter-associated urinary tract infection, Clostridium difficile infection, surgical site infection, and ventilator-associated pneumonia, but there have been less distinct successes nationally and internationally for these other HAIs.

The literature emphasizes that there are several evidence-based measures that can prevent CLABSI. These include hand hygiene, using alcoholic chlorhexidine for skin preparation prior to insertion, maximal sterile barrier precautions, avoiding the femoral site for CVC insertion, and removing unnecessary catheters as soon as possible. Support from administration in emphasizing patient safety and HAI prevention along with following evidence-based practice could lead to long-term improvement in CLABSI prevention across hospital systems.

Corresponding author: Payal K. Patel, MD, MPH, Div of Infectious Diseases, Dept of Internal Medicine, VA Ann Arbor Healthcare System, 2215 Fuller Rd, Ann Arbor, MI 48105, [email protected].

Financial disclosures: None.

Division of Infectious Diseases, Department of Internal Medicine, VA Ann Arbor Healthcare System and University of Michigan Health System, Ann Arbor, MI.

Abstract

• Objective: To review prevention of central line–associated bloodstream infection (CLABSI).
• Method: Review of the literature.
• Results: Evidence-based prevention practices include ensuring hand hygiene before the procedure, using maximal sterile barrier precautions, cleaning the skin with alcoholic chlorhexidine before central line insertion, avoiding the femoral site for insertion, and removing unneeded catheters.
• Conclusion: For continued success in CLABSI prevention, best practices should be followed and patient safety should be emphasized.

Health care–associated infections (HAIs) are a preventable cause of morbidity and mortality in the United States and internationally. A Centers for Disease Control and Prevention (CDC) report estimates that in acute care hospitals, 1 in 25 patients end up with at least one HAI during their hospital stay [1]. HAIs can also be costly; in the United States, the indirect and direct cost has been estimated to be between $96 to $147 billion dollars [2]. National initiatives to prevent these types of infections have included efforts from the Department of Health and Human Services (HHS), the Institute of Medicine (IOM), the Institute for Healthcare Improvement (IHI) and the Centers for Medicare and Medicaid Services (CMS). This work has led to particular success in preventing central line–associated bloodstream infection (CLABSI).

CLABSI can lead to considerable mortality, morbidity, and cost. An estimated 250,000 CLABSIs occur in patients yearly, and about 80,000 of those are estimated to occur in the intensive care unit (ICU) setting [3]. Since central venous catheters (CVCs), or central lines, are most often used in the ICU setting, much of the work on prevention and management of CLABSI has been within the ICU population [4,5]. The increased use of peripherally inserted central catheters (PICCs) in the non-ICU setting and recognition of CLABSI in non-ICU settings has led to new efforts to understand the best way to prevent CLABSI in the non-ICU setting [4,6]. Regardless of setting, the annual cost of these infections has been estimated to be as high as $2.3 billion [7]. One episode is estimated to cost a hospital up to $46,485 per episode with components of excess length of stay, antibiotic cost, and cost of care [8]. In this review, selected best practices in CLABSI prevention are identified and described.

Elements of CLABSI Prevention

One of the key papers in the CLABSI literature was the Keystone ICU project in Michigan [9]. This state-wide effort grew out of a successful pilot patient-safety program that was trialed at Johns Hopkins Medical Institutions to reduce CLABSI in the ICU setting. In 2003, the Agency for Healthcare Research and Quality (AHRQ) funded a study to examine the intervention in ICUs in the state of Michigan. A total of 108 ICUs from 67 individual hospitals participated in the pre-intervention/post-intervention study [9]. A combination of technical and socio-adaptive interventions to prevent CLABSI included clinician education on best practices in insertion of central lines, having a central-line cart in each ICU, an insertion checklist of best practices, empowering nursing staff to stop the procedure if best practices were not being followed, discussing removal of catheters daily, and providing feedback to units regarding rates of CLABSI [10]. Executive administration of each hospital was also involved and there were monthly phone calls for hospital teams to share successes and barriers.

In the pre-intervention phase, the median catheter- related bloodstream infection rate was 2.7 infections per 1000 catheter days for the sum of hospitals. After the interventions were put in place, the median rate of catheter related bloodstream infections was down to 0.34 at 18 months. The study showed that results from a relatively inexpensive and straightforward intervention could be effective and could last in the long term. This study led to many other single center and multicenter studies, nationally and internationally, to replicate results in efforts to decrease CLABSI in ICU populations [5]. The CDC and AHRQ have continued to partner with regional, state and national efforts to focus on CLABSI prevention.

The Bundle Approach

A number of interventions have been proven to be effective at preventing CLABSI. Combining more than one intervention can often have additive effects. This effect has been recognized in numerous quality improvement studies on CLABSI and has been termed using the “bundle” approach. 

Hand Hygiene

Poor hand hygiene by health care workers is generally thought to be the most common cause of HAIs [12]. Guidelines recommend an alcohol-based waterless product or antiseptic soap and water prior to catheter insertion [13]. The most common underlying etiology of CLABSI is through microorganisms introduced at time of insertion of catheter. This can be extraluminally mediated via skin flora of the patient, or due to lack of hand washing on the inserter’s part and can lead to CLABSI [14]. While a randomized controlled trial would be unethical, several studies have shown when targeted hand hygiene campaigns are held, CLABSI rates tend to decrease [15–17].

Maximal Barrier Precautions

The use of maximal sterile barrier precautions has been associated with less mortality, decreasing catheter colonization, incidence of HAI and cost savings [18–20]. Like most components of the bundle, maximal sterile barrier precautions have rarely been studied alone, but are often a part of a “bundle” or number of interventions [21]. Like hand hygiene, while regularly a part of many hospital’s checklist or bundle process, compliance with this key part of infection prevention can be deficient; one study noted measured maximal sterile barriers compliance to be 44% [22].

Chlorhexidine Skin Antisepsis

Chlorhexidine skin preparation decreases bacterial burden at site of insertion and is thought to reduce infection from this mechanism. Chlorhexidine-alcohol skin preparation has been proven in randomized controlled trials to outperform povidone iodine-alcohol in preventing CLABSI [23,24]. Chlorhexidine skin preparation is considered a technical element of checklists and is thought to be a straightforward and easily implementable action [25]. If a hospital supplies only alcoholic chlorhexidine and doesn’t provide povidone-iodine for skin preparation, then clinicians can be “nudged” towards performing this part of the bundle.

Optimal Catheter Site Selection

For all sites of insertion of CVC, the risk of mechanical and infectious complications depends on the skill and proficiency of operators, the clinical situation, and the availability of ultrasound to help guide placement. These factors are important in determining which anatomical site is best for each patient [26]. The femoral site has been associated with a greater risk of catheter-related infection and catheter-related thrombosis and is not recommended as the initial choice for non-emergent CVC insertion according to national guidelines [13,27]. The internal jugular vein site is associated with a lower risk of severe mechanical complications such as pneumothorax when compared to subclavian vein site [27]. The subclavian vein site is associated with a lower risk of catheter-related blood stream infection and lower rate of thrombosis, but this greatly depends on experience of operator. Experts have proposed that the subclavian site has a lower burden of colonization by bacteria than other sites and is anatomically more protected by catheter dressing; also the subcutaneous course of the central line itself is longer for the subclavian site than other sites and these reasons could contribute to the lower risk of infection [28]. The subclavian site is, however, associated with a higher risk of mechanical complications that can be serious for ICU patients. In general, the femoral vein site should be avoided in non-emergent line placement situations, particularly if the patient is an obese adult [13]. Using ultrasound as a guidance for catheter insertion has also been shown to reduce risk of CLABSI and other mechanical complications and is recommended [29,30].

Daily Review of Line Necessity

Removing unnecessary catheters as soon as possible decreases catheter dwell time and risk of infection. Few studies have concentrated on this step alone in CLABSI prevention, but the studies that have focused on catheter removal usually implement electronic reminders or multidisciplinary catheter rounds (where need for catheter is incorporated into daily rounds or discussed separately by a multidisciplinary group) [5,31].

Additional Considerations

Other basic practices that all hospitals should adopt include the above strategies and providing all inclusive catheter carts or kits, disinfecting hubs in maintenance care of catheters, covering the CVC site with sterile dressings, having recurrent educational interventions and using checklists to assure adherence to the evidence-based bundle (Table) [4,13]. As prevalence of non-ICU central lines has also grown, maintenance care is particularly important in reducing CLABSI. Maintenance bundles that highlight best practices such as aseptic technique, correct hand hygiene, chlorhexidine skin disinfection scrub, antimicrobial bandage application, and catheter hub disinfection have been used with success [32]. Specialized CVC insertion teams with trained personnel have also been recommended [4]. When these basic evidence-based practices are still unable to bring down CLABSI rates for select populations or during an outbreak, supplemental strategies can be tried to reduce CLABSI. These include antimicrobial-impregnated catheters, chlorhexidine-impregnated dressings, and chlorhexidine bathing, which is increasingly being used in the ICU setting [5,13,33].

Epidemiology/Risk Factors

At-risk Populations

ICU patients are at risk for CLABSI because of frequent use of multiple catheters, and the comorbidities and acuity of care that these patients have. ICU patients also tend to have lots of manipulation of their catheters and often these catheters are placed in emergent situations [13]. Patients in the non-ICU and outpatient setting are also at risk for CLABSI when they have a central venous catheter. Long courses of antibiotics for disease states such as osteomyelitis and endocarditis often entail central venous catheters. Recent work has shown that PICCs carry as high of a CLABSI risk as short-term CVCs in hospitalized patients [34]. Patients with end-stage renal disease, especially those undergoing maintenance hemodialysis via a tunneled dialysis catheter are particularly vulnerable to CLABSI [13,35].

Risk Factors for CLABSI

A number of studies have reviewed risk factors and epidemiology of CLABSI in the adult and pediatric population. Factors that have been associated with risk of CLABSI in more than one study include prolonged hospitalization before placement of the central line, prolonged duration of the central line, heavy microbial colonization at the site of insertion, heavy microbial colonization of the catheter hub, multiple lumens, internal jugular site catheterization, femoral vein site catheterization, neutropenia of the patient, a reduced nurse to patient ratio in the ICU setting, presence of total parenteral nutrition, and poor maintenance care of the catheter [4,13,36–40]. One study [41] that calculated a score to help predict risk of PICC-CLABSI found that previous CLABSI (within 3 months of PICC insertion) significantly increases risk of repeat CLABSI.

Conclusion

CLABSI is an important cause of morbidity, mortality and cost. There has been remarkable success in prevention of these infections in recent years due to focused efforts on patient safety. As efforts have multiplied to put into place interventions to decrease CLABSI nationally, the CDC published a Vital Signs report discussing the impact of these efforts [42]. It was estimated that over one decade, infection prevention efforts had avoided 25,000 CLABSIs in U.S. ICUs, a 58% reduction in this infection [42]. CLABSI has served as the best example of using evidence-based interventions through an infection prevention bundle or framework to reduce HAIs. Similar approaches are being used to try to reduce catheter-associated urinary tract infection, Clostridium difficile infection, surgical site infection, and ventilator-associated pneumonia, but there have been less distinct successes nationally and internationally for these other HAIs.

The literature emphasizes that there are several evidence-based measures that can prevent CLABSI. These include hand hygiene, using alcoholic chlorhexidine for skin preparation prior to insertion, maximal sterile barrier precautions, avoiding the femoral site for CVC insertion, and removing unnecessary catheters as soon as possible. Support from administration in emphasizing patient safety and HAI prevention along with following evidence-based practice could lead to long-term improvement in CLABSI prevention across hospital systems.

Corresponding author: Payal K. Patel, MD, MPH, Div of Infectious Diseases, Dept of Internal Medicine, VA Ann Arbor Healthcare System, 2215 Fuller Rd, Ann Arbor, MI 48105, [email protected].

Financial disclosures: None.

From the Center for Nursing Science & Clinical Inquiry (Dr. McCarthy), and Nutrition Care Division, (Ms. Phipps), Madigan Army Medical Center, Tacoma, WA.

Abstract

• Background: Many controversies exist in the field of nutrition support today, particularly in the critical care environment where nutrition plays a more primary rather than adjunctive role.
• Objective: To provide a brief review of current controversies regarding nutrition therapy in the ICU focusing on the choices regarding the nutrition regimen and the safe, consistent delivery of nutrition as measured by clinical outcomes.
• Methods: Selected areas of controversy are discussed detailing the strengths and weaknesses of the research behind opposing opinions.
• Results: ICU nutrition support controversies include enteral vs parenteral nutrition, use of supplmental parenteral nutrition, protein quantity and quality, and polymeric vs immune-modulating nutrients. Issues surrounding the safety of nutrition support therapy include gastric vs small bowel feeding and trophic vs full feeding. Evidence-based recommendations published by professional societies are presented.
• Conclusion: Understanding a patient’s risk for disease and predicting their response to treatment will assist clinicians with selecting those nutrition interventions that will achieve the best possible outcomes.

According to the National Library of Medicine’s translation of the Hippocratic oath, nowhere does it explicitly say “First, do no harm.” What is written is this: “I will use those dietary regimens which will benefit my patients according to my greatest ability and judgement, and I will do no harm or injustice to them” [1]. In another renowned text, one can find this observation regarding diet by a noted scholar, clinician, and the founder of modern nursing, Florence Nightingale: “Every careful observer of the sick will agree in this that thousands of patients are annually starved in the midst of plenty, from want of attention to the ways which alone make it possible for them to take food” [2,]. While Nightingale was alluding to malnutrition of hospitalized patients, it seems that her real concern may have been the iatrogenic malnutrition that inevitably accompanies hospitalization, even today [3].

From these philosophic texts, we have two ongoing controversies in modern day nutrition therapy identified: (1) what evidence do we have to support the choice of dietary regimens (ie, enteral vs parenteral therapy, timing of supplemental parenteral nutrition, standard vs high protein formula, polymeric vs immune-modulating nutrients) that best serve critically ill patients, and (2) how do we ensure that ICU patients are fed in a safe, consistent, and effective manner (gastric vs small bowel tube placement, gastric residual monitoring or not, trophic vs full feeding) as measured by clinically relevant outcomes? Many controversies exist in the field of nutrition support today [4–7] and a comprehensive discussion of all of them is beyond the scope of this paper. In this paper we will provide a brief review of current controversies focusing on those mentioned above which have only recently been challenged by new rigorous randomized clinical trials (RCTs), and in some cases, subsequent systematic reviews and meta-analyses [8–11].

The Path to Modern Day Nutrition Support Therapy

The field of nutrition support, in general, has expanded greatly over the last 4 decades, but perhaps the most notable advancements have occurred in the critical care environment where efforts have been directed at advancing our understanding of the molecular and biological effects of nutrients in maintaining homeostasis in the critically ill [6]. In recent years, specialized nutrition, delivered by the enteral or parenteral route, was finally recognized for its contribution to important clinical outcomes in the critically ill population [12]. Critical care clinicians have been educated about the advances in nutrition therapy designed to address the unique needs of a vulnerable population where survival is threatened by poor nutritional status upon admission, compromised immune function, weakened respiratory muscles with decreased ventilation capacity, and gastrointestinal (GI) dysfunction [6]. The rapid deterioration seen in these patients is exaggerated by the all too common ICU conditions of systemic inflammatory response syndrome (SIRS), sepsis, hemodynamic instability, respiratory failure, coagulation disorders, and acute kidney injury [13,14].

Beginning in the early 1990s, formulations of enteral nutrition (EN) contained active nutrients that reportedly reduced oxidative damage to cells and tissues, modulated inflammation, and improved feeding tolerance. These benefits are now referred to as the non-nutritive benefits of enteral feeding [15]. For the next 20 years, scientific publications released new results from studies examining the role of omega-3 fatty acids, antioxidant vitamins, minerals such as selenium and zinc, ribonucleotides, and conditionally essential amino acids like glutamine and arginine, in healing and recovery from critical illness. The excitement was summarized succinctly by Hegazi and Wischmeyer in 2011 when they remarked that the modern ICU clinician now has scientific data to guide specialized nutrition therapy, for example, choosing formulas supplemented with anti-inflammatory, immune-modulating, or tolerance-promoting nutrients that have the potential to enhance natural recovery processes and prevent complications [16].

The improvements in nutritional formulas were accompanied by numerous technological advances including bedside devices (electromagnetic enteral access system, real-time image-guided disposable feeding tube, smart feeding pumps with water flush technology) that quickly and safely establish access for small bowel feedings, which help minimize risk of gastric aspiration and ventilator-associated pneumonia, promote tolerance, decrease radiologic exposure, and may reduce nursing time consumed by tube placements, GI dysfunction, and patient discomfort [17–20]. Nasogastric feeding remains the most common first approach, with local practices, contraindications, and ease of placement usually determining the location of the feeding tube [5]. The advancements helped to overcome the many barriers to initiating and maintaining feedings and thus, efforts to feed critically ill patients early and effectively became more routine, along with nurse, patient, and family satisfaction. In conjunction with the innovative approaches to establishing nutrition therapy, practice guidelines published by United States, European, and Canadian nutrition societies became widely available in the past decade with graded evidence-based recommendations for who, when, what, and how to feed, and unique considerations for various critically ill populations [12,21,22]. The tireless efforts by the nutrition societies to provide much needed guidelines for clinicians were appreciated, yet there was a wide range in the grade of the recommendations, with many based on expert opinion alone. In some cases, the research conducted lacked rigor or had missing data with obvious limits to the generalizability of results. Nevertheless, for the 7 years between the publication of the old and newly revised Society of Critical Care Medicine (SCCM)/ American Society of Parenteral and Enteral Nutrition (ASPEN) Guidelines (2016), [12,23] nutrition therapy was a high-priority intervention in most ICUs. The goal was to initiate feeding within 48 hours, select an immune-modulating or other metabolic support formula, and aggressively advance the rate to 80% to 100% of goal to avoid caloric deficit, impaired intestinal integrity, nitrogen losses, and functional impairments [9,24,25]. Nutrition support evolved from adjunctive care to its rightful place in the ABCD mnemonic of early priorities of ICU care: Airway, Breathing, Circulation, Diet.

The 2016 joint publication of the SCCM/ASPEN guidelines includes primarily randomized controlled trial (RCT) data, along with some observational trial data, indexed in any major publication database through December 2013. In these guidelines there were 98 recommendations, of which only 5 were a Level 1A; most of the recommendations were categorized as “expert consensus” [12]. The results of several important clinical trials in the United States and Europe that were underway at the time have since been published and compared to the SCCM/ASPEN relevant recommendations [7]. The results have forced nutrition support clinicians to take a step back and re-examine their practice. For many seasoned clinicians who comprised the nutrition support teams of the 1980s and 1990s, it feels like a return to the basics. Until biology-driven personalized medicine is commonplace and genotype data is readily available to guide nutrition therapy for each critically ill patient, standard enteral feeding that begins slow and proceeds carefully over 5 to 7 days towards 80% of goal caloric intake under judicious monitoring of biochemical and metabolic indices may be the “best practice” today, without risk of harm [15,26]. As in all aspects of clinical care, this practice is not without controversy.

ICU Nutrition Support Controversies Today

Enteral vs Parenteral Nutrition

There is universal consensus that EN is the preferred route for nutrition therapy due to the superior physiological response and both nutritional and non-nutritional benefits [24]. Changes in gut permeability tend to occur as illness progresses and consequences include increased bacterial challenge, risk for multiple organ dysfunction syndrome, and systemic infection. It is best to intervene with nutrition early, defined as within the first 48 hours of ICU admission, while the likelihood of success and opportunity to impact the disease process is greater [12]. Early initiation of feeding provides the necessary nutrients to support gut-associated lymphoid tissue (GALT), mucosal-associated lymphoid tissue (MALT), and preserve gut integrity and microbial diversity [27]. The intestine is an effective barrier against bacteria and intraluminal toxins due to the high rate of enterocyte turnover, the mucus secreted by the goblet cells, and the large amount of protective immunological tissue; 80% of the immunoglobulins are synthesized in the GI tract [28]. Fasting states for procedures or delays in feeding longer than 3 days for any reason may contribute to disruption of intestinal integrity through atrophy and derangements in the physical structure and function of the microvilli and crypts [29]. Intestinal dysfunction leads to increased intestinal permeability and the possibility of bacterial translocation. Intestinal ischemia resulting from shock and sepsis may produce hypoxia and reperfusion injuries further affecting intestinal wall permeability [29]. In surgical patients, early enteral feeding has been found to reduce inflammation, oxidative stress, and the catabolic response to anesthesia and surgical-induced stress, help restore intestinal motility, reverse enteric mucosal atrophy, and improve wound healing [26].

We did not have sufficient data to refute the benefits of EN over PN until the paper by Harvey et al (2014), which reported no difference in mortality or infectious complications in ICU patients receiving EN or PN within 36 hours of admission and for up to 5 days [30]. This was the largest published pragmatic RCT, referred to as the CALORIES trial, which analyzed 2388 patients from 33 ICUs and resulted in controversy over what was an unchallenged approach up until this time. It was only a matter of time before other investigators would set out to confirm or negate this finding, which is what Elke and coworkers (2016) did a few years later [31]. They performed an updated systematic review and meta-analysis to evaluate the overall effect of the route of nutrition (EN versus PN) on clinical outcomes in adult critically ill patients. Similar to the Harvey et al report, they found no difference in mortality between the two routes of nutrition. However, unlike the earlier report, patients receiving EN compared to PN had a significant reduction in the number of infectious complications and ICU length of stay. No significant effect was found for hospital length of stay or days requiring mechanical ventilation. The authors suggest that EN delivery of macronutrients below predefined targets may be responsible as PN is more likely to meet or exceed these targets and overwhelm metabolic capacity in the early days of critical illness [31].

The most recent trial prompting even more discussion about early PN versus early EN in mechanically ventilated ICU patients in shock is the Reignier et al (2018) NUTRIREA-2 trial involving 2410 patients from 44 ICUs in France [32]. The investigators hypothesized that outcomes would be better with early exclusive EN compared to early exclusive PN; their hypothesis was not supported by the results, which found no difference in 28-day mortality or ICU-acquired infections. Also unexpected was the higher cumulative incidence of gastrointestinal complications including vomiting, diarrhea, bowel ischemia, and acute colonic obstruction in the EN group. The trial was stopped early after an interim analysis determined that additional enrollment was not likely to significantly change the results of the trial. Given the similarities between the CALORIES trial and this NUTRIREA-2 trial, clinicians now have mounting evidence that equivalent options for nutrition therapy exist and an appropriate selection should be made based on patient-specific indications and treatment goals. In summary, EN remains preferable to PN for the majority of adult critically ill patients due to crucial support of gut integrity, but the optimal dose or rate of delivery to favorably influence clinical outcomes in the first few days following admission remains unknown.

Use of Supplemental Parenteral Nutrition

Both the nutrition support and bench science communities have learned a great deal about PN over the 4 decades it has been in existence, with the most compelling data coming from more recent trials [31–38]. This is because it has taken many years to recover from the days of hyperalimentation or overfeeding ICU patients by providing excessive calories to meet the elevated energy demands and to reverse the hypercatabolism of critical illness. This approach contributed to the complications of hyperglycemia, hyperlipidemia, increased infectious complications, and liver steatosis, all of which gave PN a negative reputation [37]. We now have adjusted the caloric distribution and the actual formulation of PN using the recent FDA-approved lipid emulsion (Soy, Medium-chain triglycerides, Olive oil, and Fish oil; SMOF) and created protocols for administering it based on specific indications, such as loss of GI integrity or demonstrated intolerance. In general, the advances in PN have led to a safer more therapeutic formulation that has its place in critical illness. Manzanares et al [40] reported a trend toward a decrease in ventilation requirement and mortality when a fish oil–containing lipid emulsion was administered to patients who were receiving nutrition support either enterally or parenterally. The meta-analysis combined all soybean oil–sparing lipid emulsions for comparison with soybean oil and was able to show the trend for improved clinical outcomes with soybean oil–sparing lipid emulsions. The main findings of this meta-analysis were that fish oil–containing lipid emulsions may reduce infections and may be associated with a tendency toward fewer mechanical ventilation days, although not mortality, when compared with soybean oil-based strategies or administration of other alternative lipid emulsions in ICU patients [40]. Recent trial results do not change the recommendation for selecting EN first but do suggest lowering the threshold for using PN when EN alone is insufficient to meet nutrition goals. A systematic review reported no benefit of early supplemental PN over late supplemental PN and cautioned that our continued inability to explain greater infectious morbidity and unresolved organ failure limits any justification for early PN [35].

Protein Quantity and Quality

The practice of providing protein in the range of 1.2–2.0 g/kg actual body weight early in critical illness is suggested by expert consensus in the 2016 SCCM/ASPEN guidelines [12]; however, the evidence for efficacy remains controversial. It is argued that the evidence for benefit comes from observational studies, not from prospective RCTs, and that the patients at high risk are often excluded from study protocols. It has also been suggested that in patients with limited vital organ function increased protein delivery may lead to organ compromise. In a recent (2017) paper, Rooyackers et al discussed the post-hoc analyses of data from the EPANIC Trial stating the statistical correlation between protein intake and outcomes indicate that protein was associated with unfavorable outcomes, possibly by inhibiting autophagy [41].

The nutrition support community may have widely varying approaches to feeding critically ill patients but most experts agree that protein may be the most important macronutrient delivered during critical illness. There is consensus that the hypercatabolism associated with stress induces proteolysis and the loss of lean muscle mass, which may affect clinical and functional outcomes beyond the ICU stay. Using multiple assessment modalities, Puthucheary et al (2013) demonstrated a reduction in the rectus femoris muscle of 12.5% over the first week of hospitalization in the ICU and up to 17.7% by day 10. These numbers imply that sufficient protein of at least 1.2 g/kg/day should be provided to minimize these losses, even if the effect on overall outcome remains unknown [42]. Evidence is lacking for whether or not we can prevent the muscle wasting that occurs in critical illness with increased protein dosing. We also need to better identify the possible risks involved with a high-protein intake at the level of the individual patient. A secondary analysis done by Heyland et al (2013) determined that no specific dose or type of macronutrient was found to be associated with improved outcome [43]. It is clear that more large-scale RCTs of protein/amino acid interventions are needed to prove that these nutrition interventions have favorable effects on clinically important outcomes, including long-term physical function.

Polymeric vs Immune-Modulating Nutrients

The Marik and Zaloga (2008) systematic review on immunonutrition in the critically ill convinced most clinicians that while fish-oil based immunonutrition improves the outcome of medical ICU patients, diets supplemented with arginine, with or without glutamine or fish oils, do not demonstrate an advantage over standard enteral products in general ICU, trauma, or burn patients[44]. What followed these trials examining early formulations of immunonutrition was decades of well-intentioned research dedicated to elucidating the mechanism of action for individual immune-modulating nutrients for various populations, including those with acute lung injury/acute respiratory distress syndrome (ARDS) [45–47], sepsis/systemic inflammatory response syndrome [48–50], head and neck cancer [51], upper and lower GI cancer [52–55], and severe acute pancreatitis [56]. Our understanding of immunonutrition and the administration of this formulation in specific disease conditions has grown considerably yet clinicians are still asking exactly what is the role of immunonutrition and who stands to benefit the most from immune-modulating nutrition therapy. The enteral formulations currently available have a proprietary composition and dosage of individual nutrients which yield unpredictable physiologic effects. In addition, the pervasive problem of underfeeding during hospitalization prevents adequate delivery of physiologic doses of nutrients thus contributing to the widely variable research results.

Prevailing expert opinion today is that the majority of critically ill patients will benefit from nutrition support initiated early and delivered consistently; the standard polymeric formula will suffice for the majority of patients with surgical ICU patients potentially deriving benefit from immunonutrition that supports a reduction in infectious complications [57]. In the recent multiple-treatment meta-analysis performed by Mazaki et al (2015) involving 74 studies and 7572 patients, immunonutrition was ranked first for reducing the incidence of 7 complications according to the surface under the cumulative ranking curve; these were as follows: any infection, 0.86; overall complication, 0.88; mortality, 0.81; wound infection, 0.79; intra-abdominal abscess, 0.98; anastomotic leak, 0.79; and sepsis, 0.92. immunonutrition was ranked second for reducing ventilator-associated pneumonia and catheter-associated urinary tract infection (CAUTI), behind immune-modulating PN. The authors stated that immuno­nutrition was efficacious for reducing the incidence of complications in GI surgery unrelated to the timing of administration [57]. The 2014 publication of results from the MetaPlus Trial [58]challenged the published recommendations for the use of immunonutrition in the medical critically ill population. This trial used high-protein immuno­nutrition or standard formula for 301 adult critically ill patients in 14 European ICUs with diagnoses such as pneumonia or infections of the urinary tract, bloodstream, central nervous system, eye, ear, nose or throat, and the skin and soft tissue. Even with higher than average target energy intakes of 70% for the high protein immunonutrition group and 80% for the high protein standard group, there were no statistically significant differences in the primary outcome of new infections, or the secondary outcomes of days on mechanical ventilation, Sequential Organ Failure Assessment scores, or ICU and hospital length of stay. However, the 6-month mortality rate of 28% was higher in the medical subgroup [58]. Using these results, as well as existing publications of negative outcomes in medical ICU patients [44,46], the SCCM/ASPEN Guidelines Committee updated its position in 2016 to suggest that immunonutrition formulations or disease-specific formulations should no longer be used routinely in medical ICU patients, including those with acute lung injury/ARDS [12]. The Committee did suggest that these formulations should be reserved for patients with traumatic brain injury and for surgical ICU patients. The benefit for ICU postoperative patients has been linked to the synergistic effect of fish oil and arginine, which must both be present to achieve outcome benefits. A meta-analysis comprised of 35 trials was conducted by Drover et al [58], who reported that administering an arginine and fish oil-containing formula postoperatively reduced infection (RR 0.78; 95% CI, 0.64 to 0.95; P = 0.01) and hospital length of stay (WMD –2.23, 95% CI, –3.80 to –0.65; P = 0.006) but not mortality, when compared to use of a standard formula. Similar results were reported in a second meta-analysis [56], thus providing supportive evidence for the current SCCM/ASPEN recommendation to use an immune-modulating formula (containing both arginine and fish oils) in the SICU for the postoperative patient who requires EN therapy [12].

Safe, Consistent, and Effective Nutrition Support Therapy

Gastric vs Small Bowel Feeding

There is a large group of critically ill patients in whom impaired gastric emptying presents challenges to feeding; 50% of mechanically ventilated patients demonstrate delayed gastric emptying, and 80% of patients with increased intracranial pressure following head injury [60]. In one prospective RCT, Huang et al (2012) showed that severely ill patients (defined by an APACHE II score > 20) fed by the nasoduodenal route experienced significantly shortened hospital LOS, fewer complications, and improved nutrient delivery compared to similar patients fed by the nasogastric route. Less severely ill patients (APACHE II < 20) showed no differences between nasogastric and nasoduodenal feeding for the same outcomes [61]. A recent systematic review [17] pooled data from 14 trials of 1109 participants who received either gastric or small bowel feeding. Moderate quality evidence suggested that post-pyloric feeding was associated with lower rates of pneumonia compared with gastric feeding (RR 0.65, 95% CI, 0.51 to 0.84). Low-quality evidence showed an increase in the percentage of total nutrient delivered to the patient by post-pyloric feeding (mean difference 7.8%, 95% CI, 1.43 to 14.18). Overall, the authors found a 30% lower rate of pneumonia associated with post-pyloric feeding. There is insufficient evidence to show that other clinically important outcomes such as duration of mechanical ventilation, mortality, or LOS were affected by the site of feeding. The American Thoracic Society and ASPEN, as well as the Infectious Diseases Society of America, have published guidelines in support of small bowel feeding in the ICU setting due to its association with reduced incidence of health care–associated infections, specifically ventilator-associated pneumonia [62]. The experts who developed the SCCM/ASPEN and Canadian guidelines stress that critically ill patients at high risk for aspiration or feeding intolerance should be fed using small bowel access [12,21]. The reality in ICU clinical practice is that many centers will begin with gastric feeding, barring absolute contraindications, and carefully monitor the patient for signs of intolerance before moving the feeding tube tip into a post-pyloric location. This follows the general recommendation by experts saying in most critically ill patients, it is acceptable to initiate EN in the stomach [12,21]. Protocols that guide management of risk prevention and intolerance typically recommend head of bed elevation, prokinetic agents, and frequent abdominal assessments [63,64].

Once the decision is made to use a post-pyloric feeding tube for nutrition therapy, the next decision is how to safely place the tube, ensure the tip is in an acceptable small bowel location, and minimize delays in feeding. Challenges related to feeding tube insertion may preclude timely advancement to nutrition goals. Placement of feeding tubes into the post-pyloric position is often done at the bedside by trained nursing or medical staff without endoscopic or fluoroscopic guidance; however, the blind bedside approach is not without risks. Success rates of this approach vary greatly depending on the patient population and provider expertise. Placement using endoscopic or fluoroscopic guidance is a safe alternative but usually requires coordinating a transport to the radiologic suite, posing safety risks and possible feeding delays for the patient [65]. Bedside use of an electromagnetic placement device (EMPD), such as Cortrak, provides yet another alternative with reports in the literature of 98% success rates for initial placement in less than 20 minutes. In a multicenter prospective study by Powers et al (2011), only one of 194 patients enrolled had data showing a discrepancy between the original EMPD verification and the final radiograph interpretation, demonstrating a 99.5% agreement between the two readings [20]. Median placement time was 12 minutes and no patient experienced an adverse event related to tube insertion using this device. The ability to monitor the location of the feeding tube tip in real time provides a desirable safety feature for the clinician performing bedside insertions. Nurses should consider incorporating the EMPD into the unit feeding protocol, as this would reduce the time to initiation of feedings with early and accurate tube insertion. Ongoing staff education and experience with the procedure are necessary elements to achieve the high rates of success often reported in the literature [66,67]. Procedural complications from placement of nasoenteral feeding tubes by all methods can be as high as 10%, with complication rates of 1% to 3% for inadvertent placement of the feeding tube in the airway alone [65]. Radiographic confirmation of tube placement is advised prior to initiating feeding, thus eliminating any possibility of misplacement and administration of formula into the lungs.

Gastric Residual Volume Monitoring

A number of factors impede the delivery of EN in the critical care setting; these include gastrointestinal intolerance, under-prescribing to meet daily requirements, frequent interruptions for procedures, and technical issues with tube placement and maintaining patency [68]. Monitoring gastric residual volumes (GRV) contributes to these factors, yet volumes do not correlate well with incidence of pneumonia [69], measures of gastric emptying, or to the incidence of regurgitation and aspiration [70,71]. However, few studies have highlighted the difficulty of obtaining an accurate GRV due to feeding tube tip location, patient position, and type of tube [69]. Several high quality studies have demonstrated that raising the cutoff value for GRV from a lower number of 50–150 mL to a higher number of 250–500 mL does not increase risk for regurgitation, aspiration, or pneumonia [70,71]. A lower cutoff value for GRV does not protect the patient from complications, often leads to inappropriate cessation, and may adversely affect outcome through reduced volume of EN infused [72]. Gastric residual volumes in the range of 200–500 mL should raise concern and lead to the implementation of measures to reduce risk of aspiration, but automatic cessation of feeding should not occur for GRV < 500 mL in the absence of other signs of intolerance [12,69]. Metheny et al (2012) conducted a survey in which more than 97% of nurses responded that they assessed intolerance by measuring GRV; the most frequently cited threshold levels for interrupting feedings were 200 mL and 250 mL [73]. While threshold levels varied widely, only 12.6% of the nurse respondents reported allowing GRV up to 500 mL before interrupting feedings. While monitoring GRV is unnecessary with small bowel feeding, the location of the feeding tube tip should be questioned if gastric contents are obtained from a small bowel tube. The use of GRV as a parameter for trending may also yield important information regarding tolerance of feeding when the patient is unable to communicate abdominal discomfort. Other objective measures to use in the assessment of tolerance include an abdominal exam with documentation of changes in bowel sounds, expanding girth, tenderness or firmness on palpation, increasing nasogastric output, and vomiting [12,68]. If there are indications of intolerance, it is appropriate to divert the tip of the feeding tube into the distal small bowel as discussed previously.

Trophic vs Full Feeding

For the patient with low nutrition risk, there is a lack of convincing data to support an aggressive approach to feeding, either EN or PN, in the first week of critical illness [7]. In recent years, results of several trials suggest early goal-directed feeding in this population may cause net harm with increased morbidity and mortality. When discussing recent controversies in critical care nutrition, one must mention the two schools of thought when it comes to full versus limited energy provision in the first week following ICU admission. Studies in animals and humans have shown a trophic effect of enteral nutrients on the integrity of the gut mucosa, a finding that has provided the rationale for instituting enteral nutrition early during critical illness [15]. However, the inability to provide enteral nutrition early may be a marker of the severity of illness (ie, patients who can be fed enterally are less ill than those who cannot) rather than a mediator of complications and poor outcomes. Compher et al (2017) stated that greater nutritional intake is associated with lower mortality and faster time to discharge alive in high-risk, chronic patients but does not seem to be significant in nutritionally low-risk patients [74]. The findings of the EPaNIC and EDEN trials raised concern that targeting goals that meet full energy needs early in critical illness does not provide benefit and may cause harm in some populations or settings [32,75]. The EDEN trial [32] left us believing that trophic feeding at 10–20 mL/hr may be just as effective as any feeding in the first few days of critical illness striving for 15% to 20% of daily goal calories. After establishing tolerance, advancing daily intake to > 50% to 65% of goal calories, and up to 80% for the highest risk patients, may be required to prevent intestinal permeability and achieve positive clinical outcomes [33].

The systematic review and meta-analysis performed by Al-Dorzi et al (2016) adds further evidence for judicious advancement of EN for critically ill patients [76]. The authors reported finding no association between the dose of caloric intake and hospital mortality. Furthermore, a lower caloric intake resulted in lower risk of bloodstream infections and the need for renal replacement therapy (in 5 of the 21 trials only). As with many other meta-analyses, the authors reported that their results are most assuredly impacted by the heterogeneity in design, feeding route, and dose prescribed and delivered [16,76,77]. Other recent trials such as Arabi et al (2015) that enrolled 894 patients with different feeding targets further confirmed that there is no difference in outcome between groups when it comes to moderate (40% to 60% of goal) vs high (70% to 100% of goal) energy intake, infection rates, or 90-day mortality. The authors summarized their findings saying feeding closer to target is associated with better outcomes compared with severe underfeeding [78]. This adds to the controversy when considering the findings of still other RCTs or meta-analyses that evaluated minimal or trophic feeding versus standard feeding rates [9,46,77]. The meta-analysis performed by Marik and Hooper concluded that there were no differences in the risk of acquired infections, hospital mortality, ICU LOS, or ventilator-free days whether patients received intentional hypocaloric or normocaloric nutrition support [9]. Similarly, there was no significant difference in overall mortality between the underfeeding and full-feeding groups (OR, 0.94; 95% CI, 0.74–1.19; I2 = 26.6%; P = 0.61) in the meta-analysis done by Choi et al (2015), although only 4 trials were included to ensure homogeneity of the population and the intervention [77]. Furthermore, the hospital LOS and ICU LOS did not differ between the 2 groups, nor did any other secondary clinical outcome, leading the authors to conclude that calorie intake of the initial EN support for ICU patients had no bearing on relevant outcomes.

Recent studies have attempted to correlate caloric intake and patient outcomes without success; achieving 100% of caloric goal has not favorably impacted morbidity and mortality. Evidence suggests that intake greater than 65% to 70% of daily caloric requirement in the first 7 to 10 days of ICU stay may be associated with poorer outcomes, particularly when parenteral nutrition is used to supplement intake to achieve the caloric target [33–35].

Conclusion

In this review we described current ICU controversies surrounding nutrition therapy and briefly discussed the data that support more than one course of action. A summary of key points covered is presented in the Table. 

Disclaimer: The views expressed in this paper are those of the authors and do not reflect the official policy of the Department of the Army, the Department of Defense, or the U.S. government.

Corresponding author: Mary S. McCarthy, PhD, RN, CNSC, 1611 Nisqually St, Steilacoom, WA 98388.

Financial disclosures: None.

From the Center for Nursing Science & Clinical Inquiry (Dr. McCarthy), and Nutrition Care Division, (Ms. Phipps), Madigan Army Medical Center, Tacoma, WA.

Abstract

• Background: Many controversies exist in the field of nutrition support today, particularly in the critical care environment where nutrition plays a more primary rather than adjunctive role.
• Objective: To provide a brief review of current controversies regarding nutrition therapy in the ICU focusing on the choices regarding the nutrition regimen and the safe, consistent delivery of nutrition as measured by clinical outcomes.
• Methods: Selected areas of controversy are discussed detailing the strengths and weaknesses of the research behind opposing opinions.
• Results: ICU nutrition support controversies include enteral vs parenteral nutrition, use of supplmental parenteral nutrition, protein quantity and quality, and polymeric vs immune-modulating nutrients. Issues surrounding the safety of nutrition support therapy include gastric vs small bowel feeding and trophic vs full feeding. Evidence-based recommendations published by professional societies are presented.
• Conclusion: Understanding a patient’s risk for disease and predicting their response to treatment will assist clinicians with selecting those nutrition interventions that will achieve the best possible outcomes.

According to the National Library of Medicine’s translation of the Hippocratic oath, nowhere does it explicitly say “First, do no harm.” What is written is this: “I will use those dietary regimens which will benefit my patients according to my greatest ability and judgement, and I will do no harm or injustice to them” [1]. In another renowned text, one can find this observation regarding diet by a noted scholar, clinician, and the founder of modern nursing, Florence Nightingale: “Every careful observer of the sick will agree in this that thousands of patients are annually starved in the midst of plenty, from want of attention to the ways which alone make it possible for them to take food” [2,]. While Nightingale was alluding to malnutrition of hospitalized patients, it seems that her real concern may have been the iatrogenic malnutrition that inevitably accompanies hospitalization, even today [3].

From these philosophic texts, we have two ongoing controversies in modern day nutrition therapy identified: (1) what evidence do we have to support the choice of dietary regimens (ie, enteral vs parenteral therapy, timing of supplemental parenteral nutrition, standard vs high protein formula, polymeric vs immune-modulating nutrients) that best serve critically ill patients, and (2) how do we ensure that ICU patients are fed in a safe, consistent, and effective manner (gastric vs small bowel tube placement, gastric residual monitoring or not, trophic vs full feeding) as measured by clinically relevant outcomes? Many controversies exist in the field of nutrition support today [4–7] and a comprehensive discussion of all of them is beyond the scope of this paper. In this paper we will provide a brief review of current controversies focusing on those mentioned above which have only recently been challenged by new rigorous randomized clinical trials (RCTs), and in some cases, subsequent systematic reviews and meta-analyses [8–11].

The Path to Modern Day Nutrition Support Therapy

The field of nutrition support, in general, has expanded greatly over the last 4 decades, but perhaps the most notable advancements have occurred in the critical care environment where efforts have been directed at advancing our understanding of the molecular and biological effects of nutrients in maintaining homeostasis in the critically ill [6]. In recent years, specialized nutrition, delivered by the enteral or parenteral route, was finally recognized for its contribution to important clinical outcomes in the critically ill population [12]. Critical care clinicians have been educated about the advances in nutrition therapy designed to address the unique needs of a vulnerable population where survival is threatened by poor nutritional status upon admission, compromised immune function, weakened respiratory muscles with decreased ventilation capacity, and gastrointestinal (GI) dysfunction [6]. The rapid deterioration seen in these patients is exaggerated by the all too common ICU conditions of systemic inflammatory response syndrome (SIRS), sepsis, hemodynamic instability, respiratory failure, coagulation disorders, and acute kidney injury [13,14].

Beginning in the early 1990s, formulations of enteral nutrition (EN) contained active nutrients that reportedly reduced oxidative damage to cells and tissues, modulated inflammation, and improved feeding tolerance. These benefits are now referred to as the non-nutritive benefits of enteral feeding [15]. For the next 20 years, scientific publications released new results from studies examining the role of omega-3 fatty acids, antioxidant vitamins, minerals such as selenium and zinc, ribonucleotides, and conditionally essential amino acids like glutamine and arginine, in healing and recovery from critical illness. The excitement was summarized succinctly by Hegazi and Wischmeyer in 2011 when they remarked that the modern ICU clinician now has scientific data to guide specialized nutrition therapy, for example, choosing formulas supplemented with anti-inflammatory, immune-modulating, or tolerance-promoting nutrients that have the potential to enhance natural recovery processes and prevent complications [16].

The improvements in nutritional formulas were accompanied by numerous technological advances including bedside devices (electromagnetic enteral access system, real-time image-guided disposable feeding tube, smart feeding pumps with water flush technology) that quickly and safely establish access for small bowel feedings, which help minimize risk of gastric aspiration and ventilator-associated pneumonia, promote tolerance, decrease radiologic exposure, and may reduce nursing time consumed by tube placements, GI dysfunction, and patient discomfort [17–20]. Nasogastric feeding remains the most common first approach, with local practices, contraindications, and ease of placement usually determining the location of the feeding tube [5]. The advancements helped to overcome the many barriers to initiating and maintaining feedings and thus, efforts to feed critically ill patients early and effectively became more routine, along with nurse, patient, and family satisfaction. In conjunction with the innovative approaches to establishing nutrition therapy, practice guidelines published by United States, European, and Canadian nutrition societies became widely available in the past decade with graded evidence-based recommendations for who, when, what, and how to feed, and unique considerations for various critically ill populations [12,21,22]. The tireless efforts by the nutrition societies to provide much needed guidelines for clinicians were appreciated, yet there was a wide range in the grade of the recommendations, with many based on expert opinion alone. In some cases, the research conducted lacked rigor or had missing data with obvious limits to the generalizability of results. Nevertheless, for the 7 years between the publication of the old and newly revised Society of Critical Care Medicine (SCCM)/ American Society of Parenteral and Enteral Nutrition (ASPEN) Guidelines (2016), [12,23] nutrition therapy was a high-priority intervention in most ICUs. The goal was to initiate feeding within 48 hours, select an immune-modulating or other metabolic support formula, and aggressively advance the rate to 80% to 100% of goal to avoid caloric deficit, impaired intestinal integrity, nitrogen losses, and functional impairments [9,24,25]. Nutrition support evolved from adjunctive care to its rightful place in the ABCD mnemonic of early priorities of ICU care: Airway, Breathing, Circulation, Diet.

The 2016 joint publication of the SCCM/ASPEN guidelines includes primarily randomized controlled trial (RCT) data, along with some observational trial data, indexed in any major publication database through December 2013. In these guidelines there were 98 recommendations, of which only 5 were a Level 1A; most of the recommendations were categorized as “expert consensus” [12]. The results of several important clinical trials in the United States and Europe that were underway at the time have since been published and compared to the SCCM/ASPEN relevant recommendations [7]. The results have forced nutrition support clinicians to take a step back and re-examine their practice. For many seasoned clinicians who comprised the nutrition support teams of the 1980s and 1990s, it feels like a return to the basics. Until biology-driven personalized medicine is commonplace and genotype data is readily available to guide nutrition therapy for each critically ill patient, standard enteral feeding that begins slow and proceeds carefully over 5 to 7 days towards 80% of goal caloric intake under judicious monitoring of biochemical and metabolic indices may be the “best practice” today, without risk of harm [15,26]. As in all aspects of clinical care, this practice is not without controversy.

ICU Nutrition Support Controversies Today

Enteral vs Parenteral Nutrition

There is universal consensus that EN is the preferred route for nutrition therapy due to the superior physiological response and both nutritional and non-nutritional benefits [24]. Changes in gut permeability tend to occur as illness progresses and consequences include increased bacterial challenge, risk for multiple organ dysfunction syndrome, and systemic infection. It is best to intervene with nutrition early, defined as within the first 48 hours of ICU admission, while the likelihood of success and opportunity to impact the disease process is greater [12]. Early initiation of feeding provides the necessary nutrients to support gut-associated lymphoid tissue (GALT), mucosal-associated lymphoid tissue (MALT), and preserve gut integrity and microbial diversity [27]. The intestine is an effective barrier against bacteria and intraluminal toxins due to the high rate of enterocyte turnover, the mucus secreted by the goblet cells, and the large amount of protective immunological tissue; 80% of the immunoglobulins are synthesized in the GI tract [28]. Fasting states for procedures or delays in feeding longer than 3 days for any reason may contribute to disruption of intestinal integrity through atrophy and derangements in the physical structure and function of the microvilli and crypts [29]. Intestinal dysfunction leads to increased intestinal permeability and the possibility of bacterial translocation. Intestinal ischemia resulting from shock and sepsis may produce hypoxia and reperfusion injuries further affecting intestinal wall permeability [29]. In surgical patients, early enteral feeding has been found to reduce inflammation, oxidative stress, and the catabolic response to anesthesia and surgical-induced stress, help restore intestinal motility, reverse enteric mucosal atrophy, and improve wound healing [26].

We did not have sufficient data to refute the benefits of EN over PN until the paper by Harvey et al (2014), which reported no difference in mortality or infectious complications in ICU patients receiving EN or PN within 36 hours of admission and for up to 5 days [30]. This was the largest published pragmatic RCT, referred to as the CALORIES trial, which analyzed 2388 patients from 33 ICUs and resulted in controversy over what was an unchallenged approach up until this time. It was only a matter of time before other investigators would set out to confirm or negate this finding, which is what Elke and coworkers (2016) did a few years later [31]. They performed an updated systematic review and meta-analysis to evaluate the overall effect of the route of nutrition (EN versus PN) on clinical outcomes in adult critically ill patients. Similar to the Harvey et al report, they found no difference in mortality between the two routes of nutrition. However, unlike the earlier report, patients receiving EN compared to PN had a significant reduction in the number of infectious complications and ICU length of stay. No significant effect was found for hospital length of stay or days requiring mechanical ventilation. The authors suggest that EN delivery of macronutrients below predefined targets may be responsible as PN is more likely to meet or exceed these targets and overwhelm metabolic capacity in the early days of critical illness [31].

The most recent trial prompting even more discussion about early PN versus early EN in mechanically ventilated ICU patients in shock is the Reignier et al (2018) NUTRIREA-2 trial involving 2410 patients from 44 ICUs in France [32]. The investigators hypothesized that outcomes would be better with early exclusive EN compared to early exclusive PN; their hypothesis was not supported by the results, which found no difference in 28-day mortality or ICU-acquired infections. Also unexpected was the higher cumulative incidence of gastrointestinal complications including vomiting, diarrhea, bowel ischemia, and acute colonic obstruction in the EN group. The trial was stopped early after an interim analysis determined that additional enrollment was not likely to significantly change the results of the trial. Given the similarities between the CALORIES trial and this NUTRIREA-2 trial, clinicians now have mounting evidence that equivalent options for nutrition therapy exist and an appropriate selection should be made based on patient-specific indications and treatment goals. In summary, EN remains preferable to PN for the majority of adult critically ill patients due to crucial support of gut integrity, but the optimal dose or rate of delivery to favorably influence clinical outcomes in the first few days following admission remains unknown.

Use of Supplemental Parenteral Nutrition

Both the nutrition support and bench science communities have learned a great deal about PN over the 4 decades it has been in existence, with the most compelling data coming from more recent trials [31–38]. This is because it has taken many years to recover from the days of hyperalimentation or overfeeding ICU patients by providing excessive calories to meet the elevated energy demands and to reverse the hypercatabolism of critical illness. This approach contributed to the complications of hyperglycemia, hyperlipidemia, increased infectious complications, and liver steatosis, all of which gave PN a negative reputation [37]. We now have adjusted the caloric distribution and the actual formulation of PN using the recent FDA-approved lipid emulsion (Soy, Medium-chain triglycerides, Olive oil, and Fish oil; SMOF) and created protocols for administering it based on specific indications, such as loss of GI integrity or demonstrated intolerance. In general, the advances in PN have led to a safer more therapeutic formulation that has its place in critical illness. Manzanares et al [40] reported a trend toward a decrease in ventilation requirement and mortality when a fish oil–containing lipid emulsion was administered to patients who were receiving nutrition support either enterally or parenterally. The meta-analysis combined all soybean oil–sparing lipid emulsions for comparison with soybean oil and was able to show the trend for improved clinical outcomes with soybean oil–sparing lipid emulsions. The main findings of this meta-analysis were that fish oil–containing lipid emulsions may reduce infections and may be associated with a tendency toward fewer mechanical ventilation days, although not mortality, when compared with soybean oil-based strategies or administration of other alternative lipid emulsions in ICU patients [40]. Recent trial results do not change the recommendation for selecting EN first but do suggest lowering the threshold for using PN when EN alone is insufficient to meet nutrition goals. A systematic review reported no benefit of early supplemental PN over late supplemental PN and cautioned that our continued inability to explain greater infectious morbidity and unresolved organ failure limits any justification for early PN [35].

Protein Quantity and Quality

The practice of providing protein in the range of 1.2–2.0 g/kg actual body weight early in critical illness is suggested by expert consensus in the 2016 SCCM/ASPEN guidelines [12]; however, the evidence for efficacy remains controversial. It is argued that the evidence for benefit comes from observational studies, not from prospective RCTs, and that the patients at high risk are often excluded from study protocols. It has also been suggested that in patients with limited vital organ function increased protein delivery may lead to organ compromise. In a recent (2017) paper, Rooyackers et al discussed the post-hoc analyses of data from the EPANIC Trial stating the statistical correlation between protein intake and outcomes indicate that protein was associated with unfavorable outcomes, possibly by inhibiting autophagy [41].

The nutrition support community may have widely varying approaches to feeding critically ill patients but most experts agree that protein may be the most important macronutrient delivered during critical illness. There is consensus that the hypercatabolism associated with stress induces proteolysis and the loss of lean muscle mass, which may affect clinical and functional outcomes beyond the ICU stay. Using multiple assessment modalities, Puthucheary et al (2013) demonstrated a reduction in the rectus femoris muscle of 12.5% over the first week of hospitalization in the ICU and up to 17.7% by day 10. These numbers imply that sufficient protein of at least 1.2 g/kg/day should be provided to minimize these losses, even if the effect on overall outcome remains unknown [42]. Evidence is lacking for whether or not we can prevent the muscle wasting that occurs in critical illness with increased protein dosing. We also need to better identify the possible risks involved with a high-protein intake at the level of the individual patient. A secondary analysis done by Heyland et al (2013) determined that no specific dose or type of macronutrient was found to be associated with improved outcome [43]. It is clear that more large-scale RCTs of protein/amino acid interventions are needed to prove that these nutrition interventions have favorable effects on clinically important outcomes, including long-term physical function.

Polymeric vs Immune-Modulating Nutrients

The Marik and Zaloga (2008) systematic review on immunonutrition in the critically ill convinced most clinicians that while fish-oil based immunonutrition improves the outcome of medical ICU patients, diets supplemented with arginine, with or without glutamine or fish oils, do not demonstrate an advantage over standard enteral products in general ICU, trauma, or burn patients[44]. What followed these trials examining early formulations of immunonutrition was decades of well-intentioned research dedicated to elucidating the mechanism of action for individual immune-modulating nutrients for various populations, including those with acute lung injury/acute respiratory distress syndrome (ARDS) [45–47], sepsis/systemic inflammatory response syndrome [48–50], head and neck cancer [51], upper and lower GI cancer [52–55], and severe acute pancreatitis [56]. Our understanding of immunonutrition and the administration of this formulation in specific disease conditions has grown considerably yet clinicians are still asking exactly what is the role of immunonutrition and who stands to benefit the most from immune-modulating nutrition therapy. The enteral formulations currently available have a proprietary composition and dosage of individual nutrients which yield unpredictable physiologic effects. In addition, the pervasive problem of underfeeding during hospitalization prevents adequate delivery of physiologic doses of nutrients thus contributing to the widely variable research results.

Prevailing expert opinion today is that the majority of critically ill patients will benefit from nutrition support initiated early and delivered consistently; the standard polymeric formula will suffice for the majority of patients with surgical ICU patients potentially deriving benefit from immunonutrition that supports a reduction in infectious complications [57]. In the recent multiple-treatment meta-analysis performed by Mazaki et al (2015) involving 74 studies and 7572 patients, immunonutrition was ranked first for reducing the incidence of 7 complications according to the surface under the cumulative ranking curve; these were as follows: any infection, 0.86; overall complication, 0.88; mortality, 0.81; wound infection, 0.79; intra-abdominal abscess, 0.98; anastomotic leak, 0.79; and sepsis, 0.92. immunonutrition was ranked second for reducing ventilator-associated pneumonia and catheter-associated urinary tract infection (CAUTI), behind immune-modulating PN. The authors stated that immuno­nutrition was efficacious for reducing the incidence of complications in GI surgery unrelated to the timing of administration [57]. The 2014 publication of results from the MetaPlus Trial [58]challenged the published recommendations for the use of immunonutrition in the medical critically ill population. This trial used high-protein immuno­nutrition or standard formula for 301 adult critically ill patients in 14 European ICUs with diagnoses such as pneumonia or infections of the urinary tract, bloodstream, central nervous system, eye, ear, nose or throat, and the skin and soft tissue. Even with higher than average target energy intakes of 70% for the high protein immunonutrition group and 80% for the high protein standard group, there were no statistically significant differences in the primary outcome of new infections, or the secondary outcomes of days on mechanical ventilation, Sequential Organ Failure Assessment scores, or ICU and hospital length of stay. However, the 6-month mortality rate of 28% was higher in the medical subgroup [58]. Using these results, as well as existing publications of negative outcomes in medical ICU patients [44,46], the SCCM/ASPEN Guidelines Committee updated its position in 2016 to suggest that immunonutrition formulations or disease-specific formulations should no longer be used routinely in medical ICU patients, including those with acute lung injury/ARDS [12]. The Committee did suggest that these formulations should be reserved for patients with traumatic brain injury and for surgical ICU patients. The benefit for ICU postoperative patients has been linked to the synergistic effect of fish oil and arginine, which must both be present to achieve outcome benefits. A meta-analysis comprised of 35 trials was conducted by Drover et al [58], who reported that administering an arginine and fish oil-containing formula postoperatively reduced infection (RR 0.78; 95% CI, 0.64 to 0.95; P = 0.01) and hospital length of stay (WMD –2.23, 95% CI, –3.80 to –0.65; P = 0.006) but not mortality, when compared to use of a standard formula. Similar results were reported in a second meta-analysis [56], thus providing supportive evidence for the current SCCM/ASPEN recommendation to use an immune-modulating formula (containing both arginine and fish oils) in the SICU for the postoperative patient who requires EN therapy [12].

Safe, Consistent, and Effective Nutrition Support Therapy

Gastric vs Small Bowel Feeding

There is a large group of critically ill patients in whom impaired gastric emptying presents challenges to feeding; 50% of mechanically ventilated patients demonstrate delayed gastric emptying, and 80% of patients with increased intracranial pressure following head injury [60]. In one prospective RCT, Huang et al (2012) showed that severely ill patients (defined by an APACHE II score > 20) fed by the nasoduodenal route experienced significantly shortened hospital LOS, fewer complications, and improved nutrient delivery compared to similar patients fed by the nasogastric route. Less severely ill patients (APACHE II < 20) showed no differences between nasogastric and nasoduodenal feeding for the same outcomes [61]. A recent systematic review [17] pooled data from 14 trials of 1109 participants who received either gastric or small bowel feeding. Moderate quality evidence suggested that post-pyloric feeding was associated with lower rates of pneumonia compared with gastric feeding (RR 0.65, 95% CI, 0.51 to 0.84). Low-quality evidence showed an increase in the percentage of total nutrient delivered to the patient by post-pyloric feeding (mean difference 7.8%, 95% CI, 1.43 to 14.18). Overall, the authors found a 30% lower rate of pneumonia associated with post-pyloric feeding. There is insufficient evidence to show that other clinically important outcomes such as duration of mechanical ventilation, mortality, or LOS were affected by the site of feeding. The American Thoracic Society and ASPEN, as well as the Infectious Diseases Society of America, have published guidelines in support of small bowel feeding in the ICU setting due to its association with reduced incidence of health care–associated infections, specifically ventilator-associated pneumonia [62]. The experts who developed the SCCM/ASPEN and Canadian guidelines stress that critically ill patients at high risk for aspiration or feeding intolerance should be fed using small bowel access [12,21]. The reality in ICU clinical practice is that many centers will begin with gastric feeding, barring absolute contraindications, and carefully monitor the patient for signs of intolerance before moving the feeding tube tip into a post-pyloric location. This follows the general recommendation by experts saying in most critically ill patients, it is acceptable to initiate EN in the stomach [12,21]. Protocols that guide management of risk prevention and intolerance typically recommend head of bed elevation, prokinetic agents, and frequent abdominal assessments [63,64].

Once the decision is made to use a post-pyloric feeding tube for nutrition therapy, the next decision is how to safely place the tube, ensure the tip is in an acceptable small bowel location, and minimize delays in feeding. Challenges related to feeding tube insertion may preclude timely advancement to nutrition goals. Placement of feeding tubes into the post-pyloric position is often done at the bedside by trained nursing or medical staff without endoscopic or fluoroscopic guidance; however, the blind bedside approach is not without risks. Success rates of this approach vary greatly depending on the patient population and provider expertise. Placement using endoscopic or fluoroscopic guidance is a safe alternative but usually requires coordinating a transport to the radiologic suite, posing safety risks and possible feeding delays for the patient [65]. Bedside use of an electromagnetic placement device (EMPD), such as Cortrak, provides yet another alternative with reports in the literature of 98% success rates for initial placement in less than 20 minutes. In a multicenter prospective study by Powers et al (2011), only one of 194 patients enrolled had data showing a discrepancy between the original EMPD verification and the final radiograph interpretation, demonstrating a 99.5% agreement between the two readings [20]. Median placement time was 12 minutes and no patient experienced an adverse event related to tube insertion using this device. The ability to monitor the location of the feeding tube tip in real time provides a desirable safety feature for the clinician performing bedside insertions. Nurses should consider incorporating the EMPD into the unit feeding protocol, as this would reduce the time to initiation of feedings with early and accurate tube insertion. Ongoing staff education and experience with the procedure are necessary elements to achieve the high rates of success often reported in the literature [66,67]. Procedural complications from placement of nasoenteral feeding tubes by all methods can be as high as 10%, with complication rates of 1% to 3% for inadvertent placement of the feeding tube in the airway alone [65]. Radiographic confirmation of tube placement is advised prior to initiating feeding, thus eliminating any possibility of misplacement and administration of formula into the lungs.

Gastric Residual Volume Monitoring

A number of factors impede the delivery of EN in the critical care setting; these include gastrointestinal intolerance, under-prescribing to meet daily requirements, frequent interruptions for procedures, and technical issues with tube placement and maintaining patency [68]. Monitoring gastric residual volumes (GRV) contributes to these factors, yet volumes do not correlate well with incidence of pneumonia [69], measures of gastric emptying, or to the incidence of regurgitation and aspiration [70,71]. However, few studies have highlighted the difficulty of obtaining an accurate GRV due to feeding tube tip location, patient position, and type of tube [69]. Several high quality studies have demonstrated that raising the cutoff value for GRV from a lower number of 50–150 mL to a higher number of 250–500 mL does not increase risk for regurgitation, aspiration, or pneumonia [70,71]. A lower cutoff value for GRV does not protect the patient from complications, often leads to inappropriate cessation, and may adversely affect outcome through reduced volume of EN infused [72]. Gastric residual volumes in the range of 200–500 mL should raise concern and lead to the implementation of measures to reduce risk of aspiration, but automatic cessation of feeding should not occur for GRV < 500 mL in the absence of other signs of intolerance [12,69]. Metheny et al (2012) conducted a survey in which more than 97% of nurses responded that they assessed intolerance by measuring GRV; the most frequently cited threshold levels for interrupting feedings were 200 mL and 250 mL [73]. While threshold levels varied widely, only 12.6% of the nurse respondents reported allowing GRV up to 500 mL before interrupting feedings. While monitoring GRV is unnecessary with small bowel feeding, the location of the feeding tube tip should be questioned if gastric contents are obtained from a small bowel tube. The use of GRV as a parameter for trending may also yield important information regarding tolerance of feeding when the patient is unable to communicate abdominal discomfort. Other objective measures to use in the assessment of tolerance include an abdominal exam with documentation of changes in bowel sounds, expanding girth, tenderness or firmness on palpation, increasing nasogastric output, and vomiting [12,68]. If there are indications of intolerance, it is appropriate to divert the tip of the feeding tube into the distal small bowel as discussed previously.

Trophic vs Full Feeding

For the patient with low nutrition risk, there is a lack of convincing data to support an aggressive approach to feeding, either EN or PN, in the first week of critical illness [7]. In recent years, results of several trials suggest early goal-directed feeding in this population may cause net harm with increased morbidity and mortality. When discussing recent controversies in critical care nutrition, one must mention the two schools of thought when it comes to full versus limited energy provision in the first week following ICU admission. Studies in animals and humans have shown a trophic effect of enteral nutrients on the integrity of the gut mucosa, a finding that has provided the rationale for instituting enteral nutrition early during critical illness [15]. However, the inability to provide enteral nutrition early may be a marker of the severity of illness (ie, patients who can be fed enterally are less ill than those who cannot) rather than a mediator of complications and poor outcomes. Compher et al (2017) stated that greater nutritional intake is associated with lower mortality and faster time to discharge alive in high-risk, chronic patients but does not seem to be significant in nutritionally low-risk patients [74]. The findings of the EPaNIC and EDEN trials raised concern that targeting goals that meet full energy needs early in critical illness does not provide benefit and may cause harm in some populations or settings [32,75]. The EDEN trial [32] left us believing that trophic feeding at 10–20 mL/hr may be just as effective as any feeding in the first few days of critical illness striving for 15% to 20% of daily goal calories. After establishing tolerance, advancing daily intake to > 50% to 65% of goal calories, and up to 80% for the highest risk patients, may be required to prevent intestinal permeability and achieve positive clinical outcomes [33].

The systematic review and meta-analysis performed by Al-Dorzi et al (2016) adds further evidence for judicious advancement of EN for critically ill patients [76]. The authors reported finding no association between the dose of caloric intake and hospital mortality. Furthermore, a lower caloric intake resulted in lower risk of bloodstream infections and the need for renal replacement therapy (in 5 of the 21 trials only). As with many other meta-analyses, the authors reported that their results are most assuredly impacted by the heterogeneity in design, feeding route, and dose prescribed and delivered [16,76,77]. Other recent trials such as Arabi et al (2015) that enrolled 894 patients with different feeding targets further confirmed that there is no difference in outcome between groups when it comes to moderate (40% to 60% of goal) vs high (70% to 100% of goal) energy intake, infection rates, or 90-day mortality. The authors summarized their findings saying feeding closer to target is associated with better outcomes compared with severe underfeeding [78]. This adds to the controversy when considering the findings of still other RCTs or meta-analyses that evaluated minimal or trophic feeding versus standard feeding rates [9,46,77]. The meta-analysis performed by Marik and Hooper concluded that there were no differences in the risk of acquired infections, hospital mortality, ICU LOS, or ventilator-free days whether patients received intentional hypocaloric or normocaloric nutrition support [9]. Similarly, there was no significant difference in overall mortality between the underfeeding and full-feeding groups (OR, 0.94; 95% CI, 0.74–1.19; I2 = 26.6%; P = 0.61) in the meta-analysis done by Choi et al (2015), although only 4 trials were included to ensure homogeneity of the population and the intervention [77]. Furthermore, the hospital LOS and ICU LOS did not differ between the 2 groups, nor did any other secondary clinical outcome, leading the authors to conclude that calorie intake of the initial EN support for ICU patients had no bearing on relevant outcomes.

Recent studies have attempted to correlate caloric intake and patient outcomes without success; achieving 100% of caloric goal has not favorably impacted morbidity and mortality. Evidence suggests that intake greater than 65% to 70% of daily caloric requirement in the first 7 to 10 days of ICU stay may be associated with poorer outcomes, particularly when parenteral nutrition is used to supplement intake to achieve the caloric target [33–35].

Conclusion

In this review we described current ICU controversies surrounding nutrition therapy and briefly discussed the data that support more than one course of action. A summary of key points covered is presented in the Table. 

Disclaimer: The views expressed in this paper are those of the authors and do not reflect the official policy of the Department of the Army, the Department of Defense, or the U.S. government.

Corresponding author: Mary S. McCarthy, PhD, RN, CNSC, 1611 Nisqually St, Steilacoom, WA 98388.

Financial disclosures: None.

From the Center for Nursing Science & Clinical Inquiry (Dr. McCarthy), and Nutrition Care Division, (Ms. Phipps), Madigan Army Medical Center, Tacoma, WA.

Abstract

• Background: Many controversies exist in the field of nutrition support today, particularly in the critical care environment where nutrition plays a more primary rather than adjunctive role.
• Objective: To provide a brief review of current controversies regarding nutrition therapy in the ICU focusing on the choices regarding the nutrition regimen and the safe, consistent delivery of nutrition as measured by clinical outcomes.
• Methods: Selected areas of controversy are discussed detailing the strengths and weaknesses of the research behind opposing opinions.
• Results: ICU nutrition support controversies include enteral vs parenteral nutrition, use of supplmental parenteral nutrition, protein quantity and quality, and polymeric vs immune-modulating nutrients. Issues surrounding the safety of nutrition support therapy include gastric vs small bowel feeding and trophic vs full feeding. Evidence-based recommendations published by professional societies are presented.
• Conclusion: Understanding a patient’s risk for disease and predicting their response to treatment will assist clinicians with selecting those nutrition interventions that will achieve the best possible outcomes.

According to the National Library of Medicine’s translation of the Hippocratic oath, nowhere does it explicitly say “First, do no harm.” What is written is this: “I will use those dietary regimens which will benefit my patients according to my greatest ability and judgement, and I will do no harm or injustice to them” [1]. In another renowned text, one can find this observation regarding diet by a noted scholar, clinician, and the founder of modern nursing, Florence Nightingale: “Every careful observer of the sick will agree in this that thousands of patients are annually starved in the midst of plenty, from want of attention to the ways which alone make it possible for them to take food” [2,]. While Nightingale was alluding to malnutrition of hospitalized patients, it seems that her real concern may have been the iatrogenic malnutrition that inevitably accompanies hospitalization, even today [3].

From these philosophic texts, we have two ongoing controversies in modern day nutrition therapy identified: (1) what evidence do we have to support the choice of dietary regimens (ie, enteral vs parenteral therapy, timing of supplemental parenteral nutrition, standard vs high protein formula, polymeric vs immune-modulating nutrients) that best serve critically ill patients, and (2) how do we ensure that ICU patients are fed in a safe, consistent, and effective manner (gastric vs small bowel tube placement, gastric residual monitoring or not, trophic vs full feeding) as measured by clinically relevant outcomes? Many controversies exist in the field of nutrition support today [4–7] and a comprehensive discussion of all of them is beyond the scope of this paper. In this paper we will provide a brief review of current controversies focusing on those mentioned above which have only recently been challenged by new rigorous randomized clinical trials (RCTs), and in some cases, subsequent systematic reviews and meta-analyses [8–11].

The Path to Modern Day Nutrition Support Therapy

The field of nutrition support, in general, has expanded greatly over the last 4 decades, but perhaps the most notable advancements have occurred in the critical care environment where efforts have been directed at advancing our understanding of the molecular and biological effects of nutrients in maintaining homeostasis in the critically ill [6]. In recent years, specialized nutrition, delivered by the enteral or parenteral route, was finally recognized for its contribution to important clinical outcomes in the critically ill population [12]. Critical care clinicians have been educated about the advances in nutrition therapy designed to address the unique needs of a vulnerable population where survival is threatened by poor nutritional status upon admission, compromised immune function, weakened respiratory muscles with decreased ventilation capacity, and gastrointestinal (GI) dysfunction [6]. The rapid deterioration seen in these patients is exaggerated by the all too common ICU conditions of systemic inflammatory response syndrome (SIRS), sepsis, hemodynamic instability, respiratory failure, coagulation disorders, and acute kidney injury [13,14].

Beginning in the early 1990s, formulations of enteral nutrition (EN) contained active nutrients that reportedly reduced oxidative damage to cells and tissues, modulated inflammation, and improved feeding tolerance. These benefits are now referred to as the non-nutritive benefits of enteral feeding [15]. For the next 20 years, scientific publications released new results from studies examining the role of omega-3 fatty acids, antioxidant vitamins, minerals such as selenium and zinc, ribonucleotides, and conditionally essential amino acids like glutamine and arginine, in healing and recovery from critical illness. The excitement was summarized succinctly by Hegazi and Wischmeyer in 2011 when they remarked that the modern ICU clinician now has scientific data to guide specialized nutrition therapy, for example, choosing formulas supplemented with anti-inflammatory, immune-modulating, or tolerance-promoting nutrients that have the potential to enhance natural recovery processes and prevent complications [16].

The improvements in nutritional formulas were accompanied by numerous technological advances including bedside devices (electromagnetic enteral access system, real-time image-guided disposable feeding tube, smart feeding pumps with water flush technology) that quickly and safely establish access for small bowel feedings, which help minimize risk of gastric aspiration and ventilator-associated pneumonia, promote tolerance, decrease radiologic exposure, and may reduce nursing time consumed by tube placements, GI dysfunction, and patient discomfort [17–20]. Nasogastric feeding remains the most common first approach, with local practices, contraindications, and ease of placement usually determining the location of the feeding tube [5]. The advancements helped to overcome the many barriers to initiating and maintaining feedings and thus, efforts to feed critically ill patients early and effectively became more routine, along with nurse, patient, and family satisfaction. In conjunction with the innovative approaches to establishing nutrition therapy, practice guidelines published by United States, European, and Canadian nutrition societies became widely available in the past decade with graded evidence-based recommendations for who, when, what, and how to feed, and unique considerations for various critically ill populations [12,21,22]. The tireless efforts by the nutrition societies to provide much needed guidelines for clinicians were appreciated, yet there was a wide range in the grade of the recommendations, with many based on expert opinion alone. In some cases, the research conducted lacked rigor or had missing data with obvious limits to the generalizability of results. Nevertheless, for the 7 years between the publication of the old and newly revised Society of Critical Care Medicine (SCCM)/ American Society of Parenteral and Enteral Nutrition (ASPEN) Guidelines (2016), [12,23] nutrition therapy was a high-priority intervention in most ICUs. The goal was to initiate feeding within 48 hours, select an immune-modulating or other metabolic support formula, and aggressively advance the rate to 80% to 100% of goal to avoid caloric deficit, impaired intestinal integrity, nitrogen losses, and functional impairments [9,24,25]. Nutrition support evolved from adjunctive care to its rightful place in the ABCD mnemonic of early priorities of ICU care: Airway, Breathing, Circulation, Diet.

The 2016 joint publication of the SCCM/ASPEN guidelines includes primarily randomized controlled trial (RCT) data, along with some observational trial data, indexed in any major publication database through December 2013. In these guidelines there were 98 recommendations, of which only 5 were a Level 1A; most of the recommendations were categorized as “expert consensus” [12]. The results of several important clinical trials in the United States and Europe that were underway at the time have since been published and compared to the SCCM/ASPEN relevant recommendations [7]. The results have forced nutrition support clinicians to take a step back and re-examine their practice. For many seasoned clinicians who comprised the nutrition support teams of the 1980s and 1990s, it feels like a return to the basics. Until biology-driven personalized medicine is commonplace and genotype data is readily available to guide nutrition therapy for each critically ill patient, standard enteral feeding that begins slow and proceeds carefully over 5 to 7 days towards 80% of goal caloric intake under judicious monitoring of biochemical and metabolic indices may be the “best practice” today, without risk of harm [15,26]. As in all aspects of clinical care, this practice is not without controversy.

ICU Nutrition Support Controversies Today

Enteral vs Parenteral Nutrition

There is universal consensus that EN is the preferred route for nutrition therapy due to the superior physiological response and both nutritional and non-nutritional benefits [24]. Changes in gut permeability tend to occur as illness progresses and consequences include increased bacterial challenge, risk for multiple organ dysfunction syndrome, and systemic infection. It is best to intervene with nutrition early, defined as within the first 48 hours of ICU admission, while the likelihood of success and opportunity to impact the disease process is greater [12]. Early initiation of feeding provides the necessary nutrients to support gut-associated lymphoid tissue (GALT), mucosal-associated lymphoid tissue (MALT), and preserve gut integrity and microbial diversity [27]. The intestine is an effective barrier against bacteria and intraluminal toxins due to the high rate of enterocyte turnover, the mucus secreted by the goblet cells, and the large amount of protective immunological tissue; 80% of the immunoglobulins are synthesized in the GI tract [28]. Fasting states for procedures or delays in feeding longer than 3 days for any reason may contribute to disruption of intestinal integrity through atrophy and derangements in the physical structure and function of the microvilli and crypts [29]. Intestinal dysfunction leads to increased intestinal permeability and the possibility of bacterial translocation. Intestinal ischemia resulting from shock and sepsis may produce hypoxia and reperfusion injuries further affecting intestinal wall permeability [29]. In surgical patients, early enteral feeding has been found to reduce inflammation, oxidative stress, and the catabolic response to anesthesia and surgical-induced stress, help restore intestinal motility, reverse enteric mucosal atrophy, and improve wound healing [26].

We did not have sufficient data to refute the benefits of EN over PN until the paper by Harvey et al (2014), which reported no difference in mortality or infectious complications in ICU patients receiving EN or PN within 36 hours of admission and for up to 5 days [30]. This was the largest published pragmatic RCT, referred to as the CALORIES trial, which analyzed 2388 patients from 33 ICUs and resulted in controversy over what was an unchallenged approach up until this time. It was only a matter of time before other investigators would set out to confirm or negate this finding, which is what Elke and coworkers (2016) did a few years later [31]. They performed an updated systematic review and meta-analysis to evaluate the overall effect of the route of nutrition (EN versus PN) on clinical outcomes in adult critically ill patients. Similar to the Harvey et al report, they found no difference in mortality between the two routes of nutrition. However, unlike the earlier report, patients receiving EN compared to PN had a significant reduction in the number of infectious complications and ICU length of stay. No significant effect was found for hospital length of stay or days requiring mechanical ventilation. The authors suggest that EN delivery of macronutrients below predefined targets may be responsible as PN is more likely to meet or exceed these targets and overwhelm metabolic capacity in the early days of critical illness [31].

The most recent trial prompting even more discussion about early PN versus early EN in mechanically ventilated ICU patients in shock is the Reignier et al (2018) NUTRIREA-2 trial involving 2410 patients from 44 ICUs in France [32]. The investigators hypothesized that outcomes would be better with early exclusive EN compared to early exclusive PN; their hypothesis was not supported by the results, which found no difference in 28-day mortality or ICU-acquired infections. Also unexpected was the higher cumulative incidence of gastrointestinal complications including vomiting, diarrhea, bowel ischemia, and acute colonic obstruction in the EN group. The trial was stopped early after an interim analysis determined that additional enrollment was not likely to significantly change the results of the trial. Given the similarities between the CALORIES trial and this NUTRIREA-2 trial, clinicians now have mounting evidence that equivalent options for nutrition therapy exist and an appropriate selection should be made based on patient-specific indications and treatment goals. In summary, EN remains preferable to PN for the majority of adult critically ill patients due to crucial support of gut integrity, but the optimal dose or rate of delivery to favorably influence clinical outcomes in the first few days following admission remains unknown.

Use of Supplemental Parenteral Nutrition

Both the nutrition support and bench science communities have learned a great deal about PN over the 4 decades it has been in existence, with the most compelling data coming from more recent trials [31–38]. This is because it has taken many years to recover from the days of hyperalimentation or overfeeding ICU patients by providing excessive calories to meet the elevated energy demands and to reverse the hypercatabolism of critical illness. This approach contributed to the complications of hyperglycemia, hyperlipidemia, increased infectious complications, and liver steatosis, all of which gave PN a negative reputation [37]. We now have adjusted the caloric distribution and the actual formulation of PN using the recent FDA-approved lipid emulsion (Soy, Medium-chain triglycerides, Olive oil, and Fish oil; SMOF) and created protocols for administering it based on specific indications, such as loss of GI integrity or demonstrated intolerance. In general, the advances in PN have led to a safer more therapeutic formulation that has its place in critical illness. Manzanares et al [40] reported a trend toward a decrease in ventilation requirement and mortality when a fish oil–containing lipid emulsion was administered to patients who were receiving nutrition support either enterally or parenterally. The meta-analysis combined all soybean oil–sparing lipid emulsions for comparison with soybean oil and was able to show the trend for improved clinical outcomes with soybean oil–sparing lipid emulsions. The main findings of this meta-analysis were that fish oil–containing lipid emulsions may reduce infections and may be associated with a tendency toward fewer mechanical ventilation days, although not mortality, when compared with soybean oil-based strategies or administration of other alternative lipid emulsions in ICU patients [40]. Recent trial results do not change the recommendation for selecting EN first but do suggest lowering the threshold for using PN when EN alone is insufficient to meet nutrition goals. A systematic review reported no benefit of early supplemental PN over late supplemental PN and cautioned that our continued inability to explain greater infectious morbidity and unresolved organ failure limits any justification for early PN [35].

Protein Quantity and Quality

The practice of providing protein in the range of 1.2–2.0 g/kg actual body weight early in critical illness is suggested by expert consensus in the 2016 SCCM/ASPEN guidelines [12]; however, the evidence for efficacy remains controversial. It is argued that the evidence for benefit comes from observational studies, not from prospective RCTs, and that the patients at high risk are often excluded from study protocols. It has also been suggested that in patients with limited vital organ function increased protein delivery may lead to organ compromise. In a recent (2017) paper, Rooyackers et al discussed the post-hoc analyses of data from the EPANIC Trial stating the statistical correlation between protein intake and outcomes indicate that protein was associated with unfavorable outcomes, possibly by inhibiting autophagy [41].

The nutrition support community may have widely varying approaches to feeding critically ill patients but most experts agree that protein may be the most important macronutrient delivered during critical illness. There is consensus that the hypercatabolism associated with stress induces proteolysis and the loss of lean muscle mass, which may affect clinical and functional outcomes beyond the ICU stay. Using multiple assessment modalities, Puthucheary et al (2013) demonstrated a reduction in the rectus femoris muscle of 12.5% over the first week of hospitalization in the ICU and up to 17.7% by day 10. These numbers imply that sufficient protein of at least 1.2 g/kg/day should be provided to minimize these losses, even if the effect on overall outcome remains unknown [42]. Evidence is lacking for whether or not we can prevent the muscle wasting that occurs in critical illness with increased protein dosing. We also need to better identify the possible risks involved with a high-protein intake at the level of the individual patient. A secondary analysis done by Heyland et al (2013) determined that no specific dose or type of macronutrient was found to be associated with improved outcome [43]. It is clear that more large-scale RCTs of protein/amino acid interventions are needed to prove that these nutrition interventions have favorable effects on clinically important outcomes, including long-term physical function.

Polymeric vs Immune-Modulating Nutrients

The Marik and Zaloga (2008) systematic review on immunonutrition in the critically ill convinced most clinicians that while fish-oil based immunonutrition improves the outcome of medical ICU patients, diets supplemented with arginine, with or without glutamine or fish oils, do not demonstrate an advantage over standard enteral products in general ICU, trauma, or burn patients[44]. What followed these trials examining early formulations of immunonutrition was decades of well-intentioned research dedicated to elucidating the mechanism of action for individual immune-modulating nutrients for various populations, including those with acute lung injury/acute respiratory distress syndrome (ARDS) [45–47], sepsis/systemic inflammatory response syndrome [48–50], head and neck cancer [51], upper and lower GI cancer [52–55], and severe acute pancreatitis [56]. Our understanding of immunonutrition and the administration of this formulation in specific disease conditions has grown considerably yet clinicians are still asking exactly what is the role of immunonutrition and who stands to benefit the most from immune-modulating nutrition therapy. The enteral formulations currently available have a proprietary composition and dosage of individual nutrients which yield unpredictable physiologic effects. In addition, the pervasive problem of underfeeding during hospitalization prevents adequate delivery of physiologic doses of nutrients thus contributing to the widely variable research results.

Prevailing expert opinion today is that the majority of critically ill patients will benefit from nutrition support initiated early and delivered consistently; the standard polymeric formula will suffice for the majority of patients with surgical ICU patients potentially deriving benefit from immunonutrition that supports a reduction in infectious complications [57]. In the recent multiple-treatment meta-analysis performed by Mazaki et al (2015) involving 74 studies and 7572 patients, immunonutrition was ranked first for reducing the incidence of 7 complications according to the surface under the cumulative ranking curve; these were as follows: any infection, 0.86; overall complication, 0.88; mortality, 0.81; wound infection, 0.79; intra-abdominal abscess, 0.98; anastomotic leak, 0.79; and sepsis, 0.92. immunonutrition was ranked second for reducing ventilator-associated pneumonia and catheter-associated urinary tract infection (CAUTI), behind immune-modulating PN. The authors stated that immuno­nutrition was efficacious for reducing the incidence of complications in GI surgery unrelated to the timing of administration [57]. The 2014 publication of results from the MetaPlus Trial [58]challenged the published recommendations for the use of immunonutrition in the medical critically ill population. This trial used high-protein immuno­nutrition or standard formula for 301 adult critically ill patients in 14 European ICUs with diagnoses such as pneumonia or infections of the urinary tract, bloodstream, central nervous system, eye, ear, nose or throat, and the skin and soft tissue. Even with higher than average target energy intakes of 70% for the high protein immunonutrition group and 80% for the high protein standard group, there were no statistically significant differences in the primary outcome of new infections, or the secondary outcomes of days on mechanical ventilation, Sequential Organ Failure Assessment scores, or ICU and hospital length of stay. However, the 6-month mortality rate of 28% was higher in the medical subgroup [58]. Using these results, as well as existing publications of negative outcomes in medical ICU patients [44,46], the SCCM/ASPEN Guidelines Committee updated its position in 2016 to suggest that immunonutrition formulations or disease-specific formulations should no longer be used routinely in medical ICU patients, including those with acute lung injury/ARDS [12]. The Committee did suggest that these formulations should be reserved for patients with traumatic brain injury and for surgical ICU patients. The benefit for ICU postoperative patients has been linked to the synergistic effect of fish oil and arginine, which must both be present to achieve outcome benefits. A meta-analysis comprised of 35 trials was conducted by Drover et al [58], who reported that administering an arginine and fish oil-containing formula postoperatively reduced infection (RR 0.78; 95% CI, 0.64 to 0.95; P = 0.01) and hospital length of stay (WMD –2.23, 95% CI, –3.80 to –0.65; P = 0.006) but not mortality, when compared to use of a standard formula. Similar results were reported in a second meta-analysis [56], thus providing supportive evidence for the current SCCM/ASPEN recommendation to use an immune-modulating formula (containing both arginine and fish oils) in the SICU for the postoperative patient who requires EN therapy [12].

Safe, Consistent, and Effective Nutrition Support Therapy

Gastric vs Small Bowel Feeding

There is a large group of critically ill patients in whom impaired gastric emptying presents challenges to feeding; 50% of mechanically ventilated patients demonstrate delayed gastric emptying, and 80% of patients with increased intracranial pressure following head injury [60]. In one prospective RCT, Huang et al (2012) showed that severely ill patients (defined by an APACHE II score > 20) fed by the nasoduodenal route experienced significantly shortened hospital LOS, fewer complications, and improved nutrient delivery compared to similar patients fed by the nasogastric route. Less severely ill patients (APACHE II < 20) showed no differences between nasogastric and nasoduodenal feeding for the same outcomes [61]. A recent systematic review [17] pooled data from 14 trials of 1109 participants who received either gastric or small bowel feeding. Moderate quality evidence suggested that post-pyloric feeding was associated with lower rates of pneumonia compared with gastric feeding (RR 0.65, 95% CI, 0.51 to 0.84). Low-quality evidence showed an increase in the percentage of total nutrient delivered to the patient by post-pyloric feeding (mean difference 7.8%, 95% CI, 1.43 to 14.18). Overall, the authors found a 30% lower rate of pneumonia associated with post-pyloric feeding. There is insufficient evidence to show that other clinically important outcomes such as duration of mechanical ventilation, mortality, or LOS were affected by the site of feeding. The American Thoracic Society and ASPEN, as well as the Infectious Diseases Society of America, have published guidelines in support of small bowel feeding in the ICU setting due to its association with reduced incidence of health care–associated infections, specifically ventilator-associated pneumonia [62]. The experts who developed the SCCM/ASPEN and Canadian guidelines stress that critically ill patients at high risk for aspiration or feeding intolerance should be fed using small bowel access [12,21]. The reality in ICU clinical practice is that many centers will begin with gastric feeding, barring absolute contraindications, and carefully monitor the patient for signs of intolerance before moving the feeding tube tip into a post-pyloric location. This follows the general recommendation by experts saying in most critically ill patients, it is acceptable to initiate EN in the stomach [12,21]. Protocols that guide management of risk prevention and intolerance typically recommend head of bed elevation, prokinetic agents, and frequent abdominal assessments [63,64].

Once the decision is made to use a post-pyloric feeding tube for nutrition therapy, the next decision is how to safely place the tube, ensure the tip is in an acceptable small bowel location, and minimize delays in feeding. Challenges related to feeding tube insertion may preclude timely advancement to nutrition goals. Placement of feeding tubes into the post-pyloric position is often done at the bedside by trained nursing or medical staff without endoscopic or fluoroscopic guidance; however, the blind bedside approach is not without risks. Success rates of this approach vary greatly depending on the patient population and provider expertise. Placement using endoscopic or fluoroscopic guidance is a safe alternative but usually requires coordinating a transport to the radiologic suite, posing safety risks and possible feeding delays for the patient [65]. Bedside use of an electromagnetic placement device (EMPD), such as Cortrak, provides yet another alternative with reports in the literature of 98% success rates for initial placement in less than 20 minutes. In a multicenter prospective study by Powers et al (2011), only one of 194 patients enrolled had data showing a discrepancy between the original EMPD verification and the final radiograph interpretation, demonstrating a 99.5% agreement between the two readings [20]. Median placement time was 12 minutes and no patient experienced an adverse event related to tube insertion using this device. The ability to monitor the location of the feeding tube tip in real time provides a desirable safety feature for the clinician performing bedside insertions. Nurses should consider incorporating the EMPD into the unit feeding protocol, as this would reduce the time to initiation of feedings with early and accurate tube insertion. Ongoing staff education and experience with the procedure are necessary elements to achieve the high rates of success often reported in the literature [66,67]. Procedural complications from placement of nasoenteral feeding tubes by all methods can be as high as 10%, with complication rates of 1% to 3% for inadvertent placement of the feeding tube in the airway alone [65]. Radiographic confirmation of tube placement is advised prior to initiating feeding, thus eliminating any possibility of misplacement and administration of formula into the lungs.

Gastric Residual Volume Monitoring

A number of factors impede the delivery of EN in the critical care setting; these include gastrointestinal intolerance, under-prescribing to meet daily requirements, frequent interruptions for procedures, and technical issues with tube placement and maintaining patency [68]. Monitoring gastric residual volumes (GRV) contributes to these factors, yet volumes do not correlate well with incidence of pneumonia [69], measures of gastric emptying, or to the incidence of regurgitation and aspiration [70,71]. However, few studies have highlighted the difficulty of obtaining an accurate GRV due to feeding tube tip location, patient position, and type of tube [69]. Several high quality studies have demonstrated that raising the cutoff value for GRV from a lower number of 50–150 mL to a higher number of 250–500 mL does not increase risk for regurgitation, aspiration, or pneumonia [70,71]. A lower cutoff value for GRV does not protect the patient from complications, often leads to inappropriate cessation, and may adversely affect outcome through reduced volume of EN infused [72]. Gastric residual volumes in the range of 200–500 mL should raise concern and lead to the implementation of measures to reduce risk of aspiration, but automatic cessation of feeding should not occur for GRV < 500 mL in the absence of other signs of intolerance [12,69]. Metheny et al (2012) conducted a survey in which more than 97% of nurses responded that they assessed intolerance by measuring GRV; the most frequently cited threshold levels for interrupting feedings were 200 mL and 250 mL [73]. While threshold levels varied widely, only 12.6% of the nurse respondents reported allowing GRV up to 500 mL before interrupting feedings. While monitoring GRV is unnecessary with small bowel feeding, the location of the feeding tube tip should be questioned if gastric contents are obtained from a small bowel tube. The use of GRV as a parameter for trending may also yield important information regarding tolerance of feeding when the patient is unable to communicate abdominal discomfort. Other objective measures to use in the assessment of tolerance include an abdominal exam with documentation of changes in bowel sounds, expanding girth, tenderness or firmness on palpation, increasing nasogastric output, and vomiting [12,68]. If there are indications of intolerance, it is appropriate to divert the tip of the feeding tube into the distal small bowel as discussed previously.

Trophic vs Full Feeding

For the patient with low nutrition risk, there is a lack of convincing data to support an aggressive approach to feeding, either EN or PN, in the first week of critical illness [7]. In recent years, results of several trials suggest early goal-directed feeding in this population may cause net harm with increased morbidity and mortality. When discussing recent controversies in critical care nutrition, one must mention the two schools of thought when it comes to full versus limited energy provision in the first week following ICU admission. Studies in animals and humans have shown a trophic effect of enteral nutrients on the integrity of the gut mucosa, a finding that has provided the rationale for instituting enteral nutrition early during critical illness [15]. However, the inability to provide enteral nutrition early may be a marker of the severity of illness (ie, patients who can be fed enterally are less ill than those who cannot) rather than a mediator of complications and poor outcomes. Compher et al (2017) stated that greater nutritional intake is associated with lower mortality and faster time to discharge alive in high-risk, chronic patients but does not seem to be significant in nutritionally low-risk patients [74]. The findings of the EPaNIC and EDEN trials raised concern that targeting goals that meet full energy needs early in critical illness does not provide benefit and may cause harm in some populations or settings [32,75]. The EDEN trial [32] left us believing that trophic feeding at 10–20 mL/hr may be just as effective as any feeding in the first few days of critical illness striving for 15% to 20% of daily goal calories. After establishing tolerance, advancing daily intake to > 50% to 65% of goal calories, and up to 80% for the highest risk patients, may be required to prevent intestinal permeability and achieve positive clinical outcomes [33].

The systematic review and meta-analysis performed by Al-Dorzi et al (2016) adds further evidence for judicious advancement of EN for critically ill patients [76]. The authors reported finding no association between the dose of caloric intake and hospital mortality. Furthermore, a lower caloric intake resulted in lower risk of bloodstream infections and the need for renal replacement therapy (in 5 of the 21 trials only). As with many other meta-analyses, the authors reported that their results are most assuredly impacted by the heterogeneity in design, feeding route, and dose prescribed and delivered [16,76,77]. Other recent trials such as Arabi et al (2015) that enrolled 894 patients with different feeding targets further confirmed that there is no difference in outcome between groups when it comes to moderate (40% to 60% of goal) vs high (70% to 100% of goal) energy intake, infection rates, or 90-day mortality. The authors summarized their findings saying feeding closer to target is associated with better outcomes compared with severe underfeeding [78]. This adds to the controversy when considering the findings of still other RCTs or meta-analyses that evaluated minimal or trophic feeding versus standard feeding rates [9,46,77]. The meta-analysis performed by Marik and Hooper concluded that there were no differences in the risk of acquired infections, hospital mortality, ICU LOS, or ventilator-free days whether patients received intentional hypocaloric or normocaloric nutrition support [9]. Similarly, there was no significant difference in overall mortality between the underfeeding and full-feeding groups (OR, 0.94; 95% CI, 0.74–1.19; I2 = 26.6%; P = 0.61) in the meta-analysis done by Choi et al (2015), although only 4 trials were included to ensure homogeneity of the population and the intervention [77]. Furthermore, the hospital LOS and ICU LOS did not differ between the 2 groups, nor did any other secondary clinical outcome, leading the authors to conclude that calorie intake of the initial EN support for ICU patients had no bearing on relevant outcomes.

Recent studies have attempted to correlate caloric intake and patient outcomes without success; achieving 100% of caloric goal has not favorably impacted morbidity and mortality. Evidence suggests that intake greater than 65% to 70% of daily caloric requirement in the first 7 to 10 days of ICU stay may be associated with poorer outcomes, particularly when parenteral nutrition is used to supplement intake to achieve the caloric target [33–35].

Conclusion

In this review we described current ICU controversies surrounding nutrition therapy and briefly discussed the data that support more than one course of action. A summary of key points covered is presented in the Table. 

Disclaimer: The views expressed in this paper are those of the authors and do not reflect the official policy of the Department of the Army, the Department of Defense, or the U.S. government.

Corresponding author: Mary S. McCarthy, PhD, RN, CNSC, 1611 Nisqually St, Steilacoom, WA 98388.

Financial disclosures: None.

Introduction

Pancreatic ductal adenocarcinoma is a challenging disease with a poor prognosis, with 5-year survival rates in the single digits (~8%).¹ Survival rates in pancreatic cancer are low in part because most patients have advanced disease at the time of diagnosis and early development of systemic metastatic disease is common, with approximately 52% of patients with newly diagnosed pancreatic cancer having metastatic disease at diagnosis.¹ Surgical resection with negative margins is the cornerstone of potentially curative therapy for localized disease, but only 15% to 20% of patients are eligible for resection at the time of initial diagnosis. Patients with unresectable and metastatic disease are offered palliative chemotherapy. Unfortunately, early recurrence is common in patients with resectable tumors who achieve a complete resection and are treated with adjuvant therapy (5-year recurrence rate ~80%).^2,3 This article reviews the management of patients with unresectable and/or metastatic pancreatic cancer. A previous article reviewed the diagnosis and staging of pancreatic cancer and the approach to neoadjuvant and adjuvant therapy in patients with resectable and borderline-resectable disease.⁴

First-Line Systemic Treatment

Case Presentation

A 72-year-old man who underwent treatment for pancreatic adenocarcinoma 18 months ago presents to the emergency department after developing poor appetite, weight loss, and abdominal discomfort and fullness without diarrhea, which has been constant for the past 2 weeks even though he has been taking analgesics and pancreatic enzymes.

The patient was diagnosed with pancreatic cancer 18 months ago after presenting with yellowish skin and sclera color; abdominal and pelvis computed tomography (CT) with intravenous contrast showed a pancreatic head mass measuring 2.6 × 2.3 cm minimally abutting the anterior surface of the superior mesenteric vein. Endoscopic ultrasound confirmed an irregular mass at the head of the pancreas and sonographic evidence suggested invasion into the portal vein. Examination of a tissue sample obtained during the procedure showed that the mass was consistent with pancreatic adenocarcinoma. Magnetic resonance imaging (MRI) performed to define venous vasculature involvement revealed a pancreatic head mass measuring 3.0 × 2.7 cm without arterial or venous vasculature invasion. The mass was abutting the portal vein and superior mesenteric veins, and a nonspecific 8-mm aortocaval lymph node was noted. The tumor was deemed to be borderline resectable, and the patient received neoadjuvant therapy with gemcitabine and nab-paclitaxel. After 4 cycles, his carbohydrate antigen (CA) 19-9 level decreased, and MRI revealed a smaller head mass (1.3 × 1.4 cm) with stable effacement of the superior mesenteric vein and no portal vein involvement; the aortocaval lymph node remained stable. He was treated with gemcitabine chemoradiotherapy prior to undergoing an uncomplicated partial pancreaticoduodenectomy. Analysis of a surgical pathology specimen revealed T3N0 disease with a closest margin of 0.1 cm. Postsurgery, the patient completed 4 cycles of adjuvant chemotherapy with gemcitabine plus capecitabine.

At his current presentation, MRI of the abdomen and pelvis reveals a new liver mass and peritoneal thickness. Serology testing reveals a CA 19-9 level of 240 U/mL, and other liver function tests are within normal limits. Biopsy of the mass confirms recurrence.

• What systemic chemotherapy would you recommend for this patient with metastatic pancreatic adenocarcinoma?

Most cases of pancreatic cancer are unresectable and/or metastatic at the time of diagnosis. Identifying treatment endpoints and the patient’s goals of care is a critical step in management. Systemic chemotherapy can provide significant survival benefit in first-line and second-line treatment compared to best supportive care. Palliative interventions also include systemic therapy, which often improves pain control and other cancer related–symptoms and hence quality of life. Participation in clinical trials should be offered to all patients. Therapy selection depends on the patient’s performance status, comorbidities, and liver profile and the results of biomarker testing and mutation analysis.

Several single-agents, including fluoropyrimidines, gemcitabine, irinotecan, platinum compounds, and taxanes, have minor objective response rates (< 10%) and a minimal survival benefit (~2 weeks) in metastatic pancreatic adenocarcinoma. Conversely, multi-agent therapies provide higher response rates and can extend overall survival (OS). Two combinations, nab-paclitaxel plus gemcitabine and FOLFIRINOX (oxaliplatin, irinotecan, leucovorin, and flourouracil), have significantly prolonged survival compared to best single-agent gemcitabine, as demonstrated in the MPACT (Metastatic Pancreatic Adenocarcinoma Clinical Trial) and PRODIGE 4/ACCORD 11 trials.^5,6 Because both multi-agent regimens are also associated with a more toxic adverse effect profile, gemcitabine monotherapy continues to be a front-line therapy for patients with multiple comorbidities, elderly frail patients (> 80 years of age), or patients who cannot tolerate other combinations.⁷

Gemcitabine-Based Therapy

Gemcitabine became a standard of care treatment for pancreatic cancer in the mid-1990s, and was tested as a second-line therapy in a multicenter phase 2 clinical trial that accrued 74 patients with metastatic pancreatic cancer who had progressed on fluorouracil therapy. In this trial, 27% of patients treated with gemcitabine achieved a clinical benefit response and the median OS was 3.85 months.⁸ The agent was generally well-tolerated with a low incidence of grade 3 or 4 toxicities. Subsequently, a randomized clinical trial compared gemcitabine to fluorouracil in the front-line setting in 126 patients with newly diagnosed advanced pancreatic cancer.⁹ Patients were randomly assigned to receive single-agent intravenous fluorouracil administered without leucovorin as a short-term infusion (600 mg/m² once weekly) or gemcitabine (1000 mg/m² weekly for up to 7 weeks followed by 1 week of rest, and then weekly for 3 out of every 4 weeks thereafter). A higher proportion of patients treated with gemcitabine had a clinical benefit response (23.8% versus 4.8%), with an improvement in a composite measure of pain (pain intensity and analgesic consumption) and performance status. Clinical responses assessed by a secondary measure, weight gain, were below 10% in both arms, but the median OS was significantly longer for the gemcitabine arm (5.65 months versus 4.4 months, P = 0.0025) and the 1-year OS rate also favored the gemcitabine arm (18% versus 2%). Grade 3/4 neutropenia was reported more frequently in the gemcitabine arm (23% versus 5%). There is no evidence that increasing the dose intensity of the fixed-dose rate of gemcitabine (1000 mg/m² per week administered as a 30-minute infusion) leads to improved antitumor activity.

Following publication of the trial conducted by Burris and colleagues,⁹ a plethora of clinical trials have tried to outperform gemcitabine monotherapy, with all trials studying gemcitabine monotherapy compared with gemcitabine plus another agent (fluorouracil, cisplatin, oxaliplatin, irinotecan, pemetrexed, novel biologics including cetuximab, bevacizumab, axitinib, sorafenib, aflibercept). These combinations have failed to significantly extend OS compared to single-agent gemcitabine, although some showed a marginal clinical benefit:

• Capecitabine¹⁰ (hazard ratio [HR] 0.86 [95% confidence interval {CI} 0.75 to 0.98])
• Erlotinib¹¹ (HR 0.81 [95% CI 0.69 to 0.99])
• Cisplatin, epirubicin, fluorouracil, gemcitabine¹² (HR 0.65 [95% CI 0.43 to 0.99])

The best outcomes were obtained with gemcitabine plus nab-paclitaxel compared to gemcitabine monotherapy. The gemcitabine/nab-paclitaxel combination has not been compared to FOLFIRINOX in the front-line setting, as the ACCORD 11 and MPACT trials were ongoing simultaneously. However, a large retrospective trial that compared use of the regimens in the US Oncology Network in the United States demonstrated similar efficacy, although more patients treated with FOLFIRINOX needed white blood cell growth factor administration.¹³

Gemcitabine/nab-paclitaxel was studied in a phase 1/2 clinical trial with 67 untreated metastatic pancreatic cancer patients.¹⁴ Patients received nab-paclitaxel at doses of 100, 125, or 150 mg/m² followed by gemcitabine 1000 mg/m² on days 1, 8, and 15 every 28 days. The maximum tolerated dose (MTD) was 1000 mg/m² of gemcitabine plus 125 mg/m² of nab-paclitaxel once a week for 3 weeks every 28 days. Dose-limiting toxicities were sepsis and neutropenia. Patients who received the MTD had a response rate of 48%, median OS of 12.2 months, and a 1-year survival rate of 48%.

The landmark phase 3 MPACT trial confirmed that adding nab-paclitaxel to gemcitabine prolongs survival compared with gemcitabine monotherapy.⁵ This multinational randomized study included 861 treatment-naive patients with a Karnofsky performance score of 70 or higher. The median OS in the nab-paclitaxel/gemcitabine group was 8.5 months, as compared to 6.7 months in the gemcitabine monotherapy group (HR for death 0.72 [95% CI 0.62 to 0.83], P < 0.001). The survival rate was 35% in the nab-paclitaxel/gemcitabine group versus 22% in the gemcitabine group at 1 year, and 9% versus 4% at 2 years. Median progression-free survival (PFS) was 5.5 months in the nab-paclitaxel/gemcitabine group, compared to 3.7 months in the gemcitabine group (HR for disease progression or death 0.69 [95% CI 0.58 to 0.82], P < 0.001). The overall response rate according to independent review was 23% compared with 7% in the 2 groups, respectively (P < 0.001). The most common adverse events of grade 3 or higher were neutropenia (38% in the nab-paclitaxel/gemcitabine group versus 27% in the gemcitabine group), fatigue (17% versus 7%), and neuropathy (17% versus 1%). Febrile neutropenia occurred in 3% of the combination group versus 1% of the montherapy group. In the nab-paclitaxel/gemcitabine group, neuropathy of grade 3 or higher improved to grade 1 or lower a median of 29 days after discontinuation of nab-paclitaxel. In 2013, nab-paclitaxel in combination with gemcitabine received U.S. Food and Drug Administration (FDA) approval as first-line therapy for metastatic pancreatic cancer.

A pilot phase 1b/2 trial that added cisplatin to nab-paclitaxel and gemcitabine in treating 24 treatment-naive metastatic pancreatic adenocarcinoma patients showed impressive tumor response (complete response 8.3%, partial response 62.5%, stable disease 16.7%, progressive disease 12.5%) and extended median OS to 16.5 months.¹⁵ A phase 1b trial conducted in Europe added capecitabine to the cisplatin, nab-paclitaxel, and gemcitabine regimen, albeit with a different schedule and doses, in 24 patients with locally advanced and metastatic disease.¹⁶ This trial demonstrated an impressive overall response rate of 67%, with 43% of patients achieving a complete metabolic response on positron emission tomography scan and the CA 19-9 level decreasing by ≥ 49% in all 19 patients who had an elevated basal value. Moreover, PFS at 6 months was 96%. After chemotherapy 17 patients remained unresectable and 7 patients were taken to surgery; of the latter group, only 1 was determined to be unresectable at the time of surgery. This regimen is being explored in a larger study in patients with stage III and IV disease.

FOLFIRINOX

A randomized phase 2 clinical trial comparing FOLFIRINOX to gemcitabine monotherapy in 88 patients with treatment-naive metastatic pancreatic cancer revealed a high response rate for FOLFIRINOX (39% versus 11%, respectively) with a tolerable toxicity profile.¹⁷ FOLFIRINOX became the front-line standard of care therapy in pancreatic adenocarcinoma after the results of the subsequent phase 3 ACCORD 11 study preplanned interim analysis showed an unprecedented significantly improved OS benefit.⁶ The ACCORD 11 trial randomly assigned 342 patients with an Eastern Cooperative Oncology Group (ECOG) score of 0 or 1 and a serum bilirubin level less than 1.5 times the upper limit of normal to receive FOLFIRINOX (oxaliplatin 85 mg/m², irinotecan 180 mg/m², leucovorin 400 mg/m², and fluorouracil 400 mg/m² given as a bolus followed by 2400 mg/m² given as a 46-hour continuous infusion, every 2 weeks) or gemcitabine at a dose of 1000 mg/m² weekly for 7 of 8 weeks and then weekly for 3 of 4 weeks. The median OS in the FOLFIRINOX group was 11.1 months as compared with 6.8 months in the gemcitabine group (HR 0.57 [95% CI 0.45 to 0.73], P < 0.001). The FOLFIRINOX group also had a longer median PFS (6.4 months versus 3.3 months, HR 0.47 [95% CI 0.37 to 0.59], P < 0.001) and higher objective response rate (31.6% versus 9.4%, P < 0.001). More adverse events were noted in the FOLFIRINOX group, including grade 3 or 4 neutropenia (46% versus 21%), febrile neutropenia (5.4% versus 1.2%), thrombocytopenia (9.1% versus 3.6%), sensory neuropathy (9% versus 0%), vomiting (15% versus 8%), fatigue (23% versus 18%), and diarrhea (13% versus 2%). Despite the greater toxicity, only 31% of the FOLFIRINOX group had a definitive degradation of quality of life, as compared to 66% in the gemcitabine group (HR 0.47 [95% CI 0.30 to 0.70], P < 0.001), thus indicating an improvement in quality of life.

Of note, combinations containing irinotecan require adequate biliary function for excretion of its active glucuronide metabolite, SN-38. Approximately 10% of patients in the United States are homozygous for the UGT1A1*28 allele polymorphism, which causes increased SN-38 bioavailability and hence a potential for severe toxicities (eg, life threatening-refractory diarrhea).¹⁸ Therefore, it is recommended that physicians start with a lower dose of irinotecan or choose a different regimen altogether in such patients.

Current Approach and Future Directions

Based on results of the ACCORD 11 and MPACT trials, both front-line regimens (nab-paclitaxel/gemcitabine and FOLFIRINOX) can be considered appropriate treatment options for treatment-naive patients with good performance status who have locally advanced unresectable or metastatic pancreatic adenocarcinoma. FOLFIRINOX has a higher objective response rate than nab-paclitaxel-gemcitabine (32% versus 23%, respectively), but the adverse effect profile favors the nab-paclitaxel/gemcitabine combination, acknowledging this conclusion is limited due to lack of a comparative trial. Modifications to both regimens have been presented at American Society of Clinical Oncology symposiums, with preliminary data showing an extended median OS and a more tolerable toxicity profile.^19,20 In a recent retrospective observational cohort comparative analysis of nab-paclitaxel/gemcitabine versus FOLFIRINOX, results showed no statistical difference in median OS. The real-world data showed that gemcitabine-based therapy is being offered commonly to elderly patients and patients with poor performance status.¹³ There is no current research proposal for conducting a direct head-to-head comparison between these 2 regimens. Based on extrapolated data from the prior mentioned trials and retrospective analysis reviews, current guidelines recommend offering younger (< 65 years old), healthier (no comorbidity contraindication) patients with excellent performance status (ECOG 0) first-line FOLFIRINOX or gemcitabine/nab-paclitaxel. Elderly patients with stable comorbidities and good performance status (ECOG 1 or 2, Karnofsky performance status ≥ 70) could be preferably considered for treatment with nab-paclitaxel/gemcitabine as first-line or modified FOLFIRINOX if performance status is excellent. Patients with poor performance status (ECOG ≥ 2), advanced age, and significant comorbidities could still be considered candidates for gemcitabine monotherapy. However, there are promising indications that the combination of gemcitabine, nab-paclitaxel, and cisplatin could be a frontline therapy in advanced pancreaticobilliary malignancies in the future.

Second-Line Systemic Treatment

Case Continued

The patient and oncologist opt to begin treatment with modified FOLFIRINOX therapy, and after the patient completes 10 cycles CT scan shows progression of disease. His oncologist decides to refer the patient to a comprehensive cancer center for evaluation for participation in clinical trials, as his performance status remains very good (ECOG 1) and he would like to seek a novel therapy. His liver mass biopsy and blood liquid biopsy are sent for tumor mutational profile evaluation; results show a high tumor mutational burden and microsatellite instability.

• What are second-line treatment options for metastatic pancreatic cancer?

Second-line regimen recommendations for metastatic pancreatic cancer depend on which agents were used in first-line therapy and the patient’s performance status and comorbidities. Patients who progressed on first-line FOLFIRINOX and continue to have a good performance status (ECOG 0 or 1) may be considered for gemcitabine/nab-paclitaxel therapy; otherwise, they may be candidates for gemcitabine plus capecitabine or gemcitabine monotherapy based on performance status and goals of care. Patients who progressed on front-line gemcitabine/nab-paclitaxel may opt for FOLFIRINOX (or an oxaliplatin-based regimen [FOLFOX] or irinotecan-based regimen [FOLFIRI] if FOLFIRINOX is not tolerable), nanoliposomal irinotecan/fluorouracil/leucovorin, or a short-term infusional fluorouracil and leucovorin regimen. The preferences for second-line treatment are not well established, and patients should be encouraged to participate in clinical trials. Chemotherapy should be offered only to those patients who maintain good performance status after progression on first-line therapy. For patients with poor performance status (ECOG 3 or 4) or multiple comorbidities, a discussion about goals of care and palliative therapy is warranted.

Gemcitabine-Based Therapy

An AGEO prospective multicenter cohort assigned 57 patients with metastatic pancreatic adenocarcinoma who had disease progression on FOLFIRINOX therapy to receive gemcitabine/nab-paclitaxel (dose as per MPACT trial).²¹ The median OS was 8.8 months and median PFS was 5.1 months after FOLFIRINOX. There were reported manageable grade 3/4 toxicities in 40% of patients, which included neutropenia (12.5%), neurotoxicity (12.5%), asthenia (9%), and thrombocytopenia (6.5%). A phase 2 clinical trial that evaluated gemcitabine monotherapy in 74 patients with metastatic pancreatic cancer who had progressed on fluorouracil showed a 3.85-month survival benefit.²²

Irinotecan-Based Regimens

The NAPOLI-1 (NAnoliPOsomaL Irinotecan) trial evaluated nanoliposomal irinotecan (MM-398, nal-IRI) and fluorouracil/leucovorin in patients with metastatic pancreatic cancer refractory to gemcitabine-based therapy.²³ This global, open-label phase 3 trial initially randomly assigned and stratified 417 patients in a 1:1 fashion to receive either nanoliposomal irinotecan monotherapy (120 mg/m² every 3 weeks, equivalent to 100 mg/m² of irinotecan base) or fluorouracil/leucovorin combination. A third treatment arm consisting of nanoliposomal irinotecan (80 mg/m², equivalent to 70 mg/m² of irinotecan base) with fluorouracil and leucovorin every 2 weeks was added later in a 1:1:1 fashion. Patients assigned to nanoliposomal irinotecan plus fluorouracil/leucovorin had a significantly improved OS of 6.1 months compared to 4.2 months with fluorouracil/leucovorin (HR 0.67 [95% CI 0.49 to 0.92], P = 0.012). The results of an intention-to-treat analysis favored the nanoliposomal irinotecan regimen, with a median OS of 8.9 months compared with 5.1 months (HR 0.57, P = 0.011). In addition, median PFS was improved in the nanoliposomal irinotecan arm (3.1 months versus 1.5 months; HR 0.56, P < 0.001), and median OS did not differ between patients treated with nanoliposomal irinotecan monotherapy and those treated with fluorouracil/leucovorin (4.9 months versus 4.2 months; HR 0.99 [95% CI 0.77 to 1.28], P = 0.94). The grade 3/4 adverse events that occurred most frequently in the 117 patients assigned to nanoliposomal irinotecan plus fluorouracil/leucovorin were neutropenia (27%), diarrhea (13%), vomiting (11%), and fatigue (14%). Nanoliposomal irinotecan combination provides another second-line treatment option for patients with metastatic pancreatic adenocarcinoma who have progressed on gemcitabine-based therapy but are not candidates for FOLFIRINOX.

Oxaliplatin-Based Regimens

Regimens that combine oxaliplatin with fluorouracil and leucovorin or capecitabine have shown superiority to fluorouracil/leucovorin or best supportive care (BSC). The CONKO study group compared oxaliplatin plus fluorouracil/leucovorin to BSC as second-line therapy in patients with advanced pancreatic cancer who progressed while on gemcitabine therapy (CONKO-003).²⁴ In this phase 3 trial, patients were randomly assigned (1:1) and stratified based on duration of first-line therapy, performance status, and tumor stage to receive BSC alone or the OFF regimen, which consisted of oxaliplatin (85 mg/m² on days 8 and 22) plus short-term infusional fluorouracil (2000 mg/m² over 24 hours) and leucovorin (200 mg/m² over 30 minutes), both given on days 1, 8, 15, and 22 of a 6-week cycle. This trial was terminated early according to predefined protocol regulations because of insufficient accrual (lack of acceptance of BSC by patients and physicians). Median second-line survival was 4.82 months for patients who received OFF treatment and 2.30 months for those who received BSC (HR 0.45 [95% CI 0.24 to 0.83], P = 0.008).  Neurotoxicity (grade 1/2) and nausea, emesis, and diarrhea (grade 2/3) were worse in the chemotherapy arm; otherwise, the regimen was well tolerated.

A later modification of the CONKO-003 trial changed the comparison arm from BSC to fluorouracil/leucovorin.²⁵ The median OS in the OFF group was 5.9 months versus 3.3 months in the fluorouracil/leucovorin group (HR 0.66 [95% CI 0.48 to 0.91], log-rank P = 0.010). Time to progression was significantly extended with OFF (2.9 months) as compared with fluorouracil/leucovorin (2.0 months; HR 0.68 [95% CI 0.50 to 0.94], log-rank P = 0.019). Rates of adverse events were similar between the treatment arms, with the exception of grades 1/2 neurotoxicity, which were reported in 38.2% and 7.1% of patients in the OFF and fluorouracil/leucovorin groups, respectively (P < 0.001).

The phase 3 PANCREOX trial failed to show superiority of modified FOLFOX6 (mFOLFOX6; infusional fluorouracil, leucovorin, and oxaliplatin) over fluorouracil/leucovorin.²⁶ A phase 2 trial of oxaliplatin plus capecitabine for second-line therapy in gemcitabine-treated advanced pancreatic cancer patients with dose adjustments for performance status (ECOG 2) and age (> 65 years) showed a median OS of 5.7 months without a comparison.²⁷ A modified oxaliplatin regimen may be a reasonable second-line therapy option for gemcitabine-treated patients who are not candidates for an irinotecan-based regimen (eg, elevated bilirubin) and continue to have an acceptable performance status.

Targeted Therapies

A variety of targeted therapies have failed to demonstrate major activity in metastatic pancreatic cancer, including bevacizumab targeting vascular endothelial growth factor, cetuximab targeting epidermal growth factor receptor, ruxolitinib targeting JAK pathway signaling, saridegib targeting the hedgehog pathway, and MK-0646 targeting insulin-like growth factor 1 receptor (IGFR). Other novel agents against targetable pathways that had promising early-phase results are currently being studied in ongoing clinical trials; these include JAK-2, PI3K, MEK, and BRAF inhibitors and immunotherapy.

Recent research efforts have focused on targeted testing of advanced pancreatic cancers for mismatch repair deficiency (dMMR) and high microsatellite instability (MSI-H) and for the germline and somatic BRCA1/2 or PALB2 mutations to determine potential eligibility for immunotherapy. Patients with these tumor characteristics and/or mutations might also be more sensitive to platinum-based chemotherapy agents or poly (ADP-ribose) polymerase (PARP) inhibitors. Germline mutations in BRCA 1/2 are present in 5% to 8% of patients with pancreatic cancer (up to 10%–15% in Ashkenazi Jewish population).²⁸ A superior median OS was retrospectively observed for patients with advanced stage BRCA 1/2-associated pancreatic adenocarcinoma who were treated with platinum-based chemotherapy agents versus those treated with non-platinum-based agents (22 versus 9 months; P = 0.039).²² PARP inhibitors have shown activity in germline BRCA1/2-associated breast (off label) and ovarian cancers (approved by the FDA). The efficacy and safety of PARP inhibitors were evaluated in a phase 2 study of a spectrum of BRCA1/2-associated cancers, including pancreatic cancer. The results revealed a tumor response rate of 21.7% (5 of 23 patients with pancreatic cancer [95% CI 7.5 to 43.7]), and 35% of patients had stable disease for a duration of 8 weeks or more (95% CI 16.4 to 57.3) with good tolerability.²⁹ Three novel PARP inhibitors are currently under clinical trial investigation in patients with germline BRCA 1/2- and PALB2-mutated metastatic pancreatic cancer: maintenance olaparib (NCT02184195) and rucaparib (NCT03140670) are both being studied as monotherapy in patients whose disease has not progressed on first-line platinum-based chemotherapy, and veliparib is being evaluated in a 3-arm study that includes gemcitabine and cisplatin with or without veliparib and single-agent maintenance veliparib (NCT01585805).

In 2017, the FDA granted accelerated approval to pembrolizumab for treatment of patients with unresectable or metastatic MSI-H or dMMR solid tumors whose disease progressed on prior treatments, making it the first oncology drug to be approved based on the genetic features of the tumor rather than its location in the body. This first tissue/site-agnostic approval was based on results from 5 single-arm trials involving 149 patients, including 5 patients with pancreatic cancer.³⁰ The objective response rate with pembrolizumab was 39.6% (95% CI 31.7 to 47.9), including a 7.4% complete response rate and a 32.2% partial response rate. The median duration of response was not reached at the time of publication (range, 1.6+ months to 22.7+ months).

Palliative and Supportive Care

Case Continued

The patient opts to participate in a novel immunotherapy clinical trial and is currently on his second cycle. He continues to have right upper quadrant pain despite opioid analgesia, has not gained any weight, and noticed new right lower extremity swelling after a recent holiday vacation to Florida.

• What supportive measures should be in place for patients with metastatic adenocarcinoma?

Most patients with advanced pancreatic adenocarcinoma will require a palliative intervention. All new unresectable pancreatic cancer patients should have an early psychosocial evaluation; identification of symptoms and implementation of preventive interventions that would improve quality of life and reduce suffering are paramount. A multidisciplinary team including physician/nursing staff, nutritionist/dietitian, palliative service, a social worker, and a case manager should be involved in patient care. More than two-thirds of patients can develop symptomatic biliary obstruction.³¹ Bile duct obstruction due to locally advanced pancreatic adenocarcinoma causes hyperbilirubinemia, which requires endoscopic placement of a metallic or plastic stent; plastic stents have a higher rate of re-occlusion.³² Appropriate bile flow allows treatment with irinotecan-based regimens. Percutaneous biliary drainage may be necessary if endoscopic intervention is not feasible.

Approximately one quarter of patients may present with gastric outlet obstruction due to duodenal obstruction.³¹ Endoscopic placement of an enteral expandable metal stent is preferred. Alternatively, percutaneous endoscopic gastrostomy tube placement may give symptomatic relief. Palliative surgical interventions are reserved for patients with greater life expectancy and in whom all other interventions have failed or are not feasible.

Almost all patients with pancreatic adenocarcinoma will experience cancer-associated pain. Intractable pain should be treated with a celiac plexus block. Radiation therapy may be considered as an adjunct therapy for pain, bleeding, and/or local obstruction. The National Comprehensive Cancer Network guidelines recommend that patients who undergo a laparotomy for potentially resectable disease but are found to have unresectable disease at the time of surgery should undergo stenting, open biliary-enteric bypass with or without gastrojejunostomy, and/or celiac plexus neurolysis.³³

Pancreatic exocrine enzyme insufficiency due to tumor extension, duct blockage, or surgical removal may cause malabsoprtive steatorrhea, contributing to cancer cachexia syndrome. Nutritional evaluation and daily oral pancreatic enzyme supplementation are recommended.³⁴

Patients diagnosed with pancreatic adenocarcinoma have a venous thromboembolism (VTE) incidence of 20 per 100 person-years (5%–60% of patients) and are considered at very high risk for VTE based on the Khorana score.³⁵ The preferred VTE treatment is low-molecular-weight heparin rather than warfarin based on the results of the CLOT study.³⁶ There is no current evidence for routine prophylactic therapy or the use of direct oral anticoagulants.

Finally, a cancer diagnosis, particularly pancreatic cancer, causes a significant amount of psychosocial stress and requires active support and counseling from a professional.

Conclusion

Pancreatic adenocarcinoma is the most lethal of all the gastrointestinal malignancies. FOLFIRINOX and gemcitabine/nab-paclitaxel are superior to gemcitabine monotherapy for patients with advanced unresectable and/or metastatic pancreatic cancer who are candidates for more aggressive therapy and are considered first-line therapies. Early data on the gemcitabine, nab-paclitaxel, and cisplatin combination appears to show superior efficacy. Second-line therapies are selected based on the patient’s performance status, first-line regimen, and residual toxicities from the prior regimen; options include gemcitabine/nab-paclitaxel, FOLFIRINOX (± oxaliplatin or irinotecan), single-agent gemcitabine (elderly frail patients), fluorouracil and liposomal-irinotecan, or referral for a clinical trial. The main challenge with pancreatic cancer is the development of stroma around the tumor, which abrogates drug delivery, allows for tumor growth in a hypoxic microenvironment, alters the metabolomics, and causes an immunosuppressive microenvironment. Drugs that target the microenvironments, such as hedgehog pathway inhibitors, have failed to show any clinical benefit, and we hope to see more efficacious microenvironment-targeted novel drugs in the future. In addition, immunotherapy has not shown any significant efficacy in clinical trials and many trials are still ongoing.

Introduction

Pancreatic ductal adenocarcinoma is a challenging disease with a poor prognosis, with 5-year survival rates in the single digits (~8%).¹ Survival rates in pancreatic cancer are low in part because most patients have advanced disease at the time of diagnosis and early development of systemic metastatic disease is common, with approximately 52% of patients with newly diagnosed pancreatic cancer having metastatic disease at diagnosis.¹ Surgical resection with negative margins is the cornerstone of potentially curative therapy for localized disease, but only 15% to 20% of patients are eligible for resection at the time of initial diagnosis. Patients with unresectable and metastatic disease are offered palliative chemotherapy. Unfortunately, early recurrence is common in patients with resectable tumors who achieve a complete resection and are treated with adjuvant therapy (5-year recurrence rate ~80%).^2,3 This article reviews the management of patients with unresectable and/or metastatic pancreatic cancer. A previous article reviewed the diagnosis and staging of pancreatic cancer and the approach to neoadjuvant and adjuvant therapy in patients with resectable and borderline-resectable disease.⁴

First-Line Systemic Treatment

Case Presentation

A 72-year-old man who underwent treatment for pancreatic adenocarcinoma 18 months ago presents to the emergency department after developing poor appetite, weight loss, and abdominal discomfort and fullness without diarrhea, which has been constant for the past 2 weeks even though he has been taking analgesics and pancreatic enzymes.

The patient was diagnosed with pancreatic cancer 18 months ago after presenting with yellowish skin and sclera color; abdominal and pelvis computed tomography (CT) with intravenous contrast showed a pancreatic head mass measuring 2.6 × 2.3 cm minimally abutting the anterior surface of the superior mesenteric vein. Endoscopic ultrasound confirmed an irregular mass at the head of the pancreas and sonographic evidence suggested invasion into the portal vein. Examination of a tissue sample obtained during the procedure showed that the mass was consistent with pancreatic adenocarcinoma. Magnetic resonance imaging (MRI) performed to define venous vasculature involvement revealed a pancreatic head mass measuring 3.0 × 2.7 cm without arterial or venous vasculature invasion. The mass was abutting the portal vein and superior mesenteric veins, and a nonspecific 8-mm aortocaval lymph node was noted. The tumor was deemed to be borderline resectable, and the patient received neoadjuvant therapy with gemcitabine and nab-paclitaxel. After 4 cycles, his carbohydrate antigen (CA) 19-9 level decreased, and MRI revealed a smaller head mass (1.3 × 1.4 cm) with stable effacement of the superior mesenteric vein and no portal vein involvement; the aortocaval lymph node remained stable. He was treated with gemcitabine chemoradiotherapy prior to undergoing an uncomplicated partial pancreaticoduodenectomy. Analysis of a surgical pathology specimen revealed T3N0 disease with a closest margin of 0.1 cm. Postsurgery, the patient completed 4 cycles of adjuvant chemotherapy with gemcitabine plus capecitabine.

At his current presentation, MRI of the abdomen and pelvis reveals a new liver mass and peritoneal thickness. Serology testing reveals a CA 19-9 level of 240 U/mL, and other liver function tests are within normal limits. Biopsy of the mass confirms recurrence.

• What systemic chemotherapy would you recommend for this patient with metastatic pancreatic adenocarcinoma?

Most cases of pancreatic cancer are unresectable and/or metastatic at the time of diagnosis. Identifying treatment endpoints and the patient’s goals of care is a critical step in management. Systemic chemotherapy can provide significant survival benefit in first-line and second-line treatment compared to best supportive care. Palliative interventions also include systemic therapy, which often improves pain control and other cancer related–symptoms and hence quality of life. Participation in clinical trials should be offered to all patients. Therapy selection depends on the patient’s performance status, comorbidities, and liver profile and the results of biomarker testing and mutation analysis.

Several single-agents, including fluoropyrimidines, gemcitabine, irinotecan, platinum compounds, and taxanes, have minor objective response rates (< 10%) and a minimal survival benefit (~2 weeks) in metastatic pancreatic adenocarcinoma. Conversely, multi-agent therapies provide higher response rates and can extend overall survival (OS). Two combinations, nab-paclitaxel plus gemcitabine and FOLFIRINOX (oxaliplatin, irinotecan, leucovorin, and flourouracil), have significantly prolonged survival compared to best single-agent gemcitabine, as demonstrated in the MPACT (Metastatic Pancreatic Adenocarcinoma Clinical Trial) and PRODIGE 4/ACCORD 11 trials.^5,6 Because both multi-agent regimens are also associated with a more toxic adverse effect profile, gemcitabine monotherapy continues to be a front-line therapy for patients with multiple comorbidities, elderly frail patients (> 80 years of age), or patients who cannot tolerate other combinations.⁷

Gemcitabine-Based Therapy

Gemcitabine became a standard of care treatment for pancreatic cancer in the mid-1990s, and was tested as a second-line therapy in a multicenter phase 2 clinical trial that accrued 74 patients with metastatic pancreatic cancer who had progressed on fluorouracil therapy. In this trial, 27% of patients treated with gemcitabine achieved a clinical benefit response and the median OS was 3.85 months.⁸ The agent was generally well-tolerated with a low incidence of grade 3 or 4 toxicities. Subsequently, a randomized clinical trial compared gemcitabine to fluorouracil in the front-line setting in 126 patients with newly diagnosed advanced pancreatic cancer.⁹ Patients were randomly assigned to receive single-agent intravenous fluorouracil administered without leucovorin as a short-term infusion (600 mg/m² once weekly) or gemcitabine (1000 mg/m² weekly for up to 7 weeks followed by 1 week of rest, and then weekly for 3 out of every 4 weeks thereafter). A higher proportion of patients treated with gemcitabine had a clinical benefit response (23.8% versus 4.8%), with an improvement in a composite measure of pain (pain intensity and analgesic consumption) and performance status. Clinical responses assessed by a secondary measure, weight gain, were below 10% in both arms, but the median OS was significantly longer for the gemcitabine arm (5.65 months versus 4.4 months, P = 0.0025) and the 1-year OS rate also favored the gemcitabine arm (18% versus 2%). Grade 3/4 neutropenia was reported more frequently in the gemcitabine arm (23% versus 5%). There is no evidence that increasing the dose intensity of the fixed-dose rate of gemcitabine (1000 mg/m² per week administered as a 30-minute infusion) leads to improved antitumor activity.

Following publication of the trial conducted by Burris and colleagues,⁹ a plethora of clinical trials have tried to outperform gemcitabine monotherapy, with all trials studying gemcitabine monotherapy compared with gemcitabine plus another agent (fluorouracil, cisplatin, oxaliplatin, irinotecan, pemetrexed, novel biologics including cetuximab, bevacizumab, axitinib, sorafenib, aflibercept). These combinations have failed to significantly extend OS compared to single-agent gemcitabine, although some showed a marginal clinical benefit:

• Capecitabine¹⁰ (hazard ratio [HR] 0.86 [95% confidence interval {CI} 0.75 to 0.98])
• Erlotinib¹¹ (HR 0.81 [95% CI 0.69 to 0.99])
• Cisplatin, epirubicin, fluorouracil, gemcitabine¹² (HR 0.65 [95% CI 0.43 to 0.99])

The best outcomes were obtained with gemcitabine plus nab-paclitaxel compared to gemcitabine monotherapy. The gemcitabine/nab-paclitaxel combination has not been compared to FOLFIRINOX in the front-line setting, as the ACCORD 11 and MPACT trials were ongoing simultaneously. However, a large retrospective trial that compared use of the regimens in the US Oncology Network in the United States demonstrated similar efficacy, although more patients treated with FOLFIRINOX needed white blood cell growth factor administration.¹³

Gemcitabine/nab-paclitaxel was studied in a phase 1/2 clinical trial with 67 untreated metastatic pancreatic cancer patients.¹⁴ Patients received nab-paclitaxel at doses of 100, 125, or 150 mg/m² followed by gemcitabine 1000 mg/m² on days 1, 8, and 15 every 28 days. The maximum tolerated dose (MTD) was 1000 mg/m² of gemcitabine plus 125 mg/m² of nab-paclitaxel once a week for 3 weeks every 28 days. Dose-limiting toxicities were sepsis and neutropenia. Patients who received the MTD had a response rate of 48%, median OS of 12.2 months, and a 1-year survival rate of 48%.

The landmark phase 3 MPACT trial confirmed that adding nab-paclitaxel to gemcitabine prolongs survival compared with gemcitabine monotherapy.⁵ This multinational randomized study included 861 treatment-naive patients with a Karnofsky performance score of 70 or higher. The median OS in the nab-paclitaxel/gemcitabine group was 8.5 months, as compared to 6.7 months in the gemcitabine monotherapy group (HR for death 0.72 [95% CI 0.62 to 0.83], P < 0.001). The survival rate was 35% in the nab-paclitaxel/gemcitabine group versus 22% in the gemcitabine group at 1 year, and 9% versus 4% at 2 years. Median progression-free survival (PFS) was 5.5 months in the nab-paclitaxel/gemcitabine group, compared to 3.7 months in the gemcitabine group (HR for disease progression or death 0.69 [95% CI 0.58 to 0.82], P < 0.001). The overall response rate according to independent review was 23% compared with 7% in the 2 groups, respectively (P < 0.001). The most common adverse events of grade 3 or higher were neutropenia (38% in the nab-paclitaxel/gemcitabine group versus 27% in the gemcitabine group), fatigue (17% versus 7%), and neuropathy (17% versus 1%). Febrile neutropenia occurred in 3% of the combination group versus 1% of the montherapy group. In the nab-paclitaxel/gemcitabine group, neuropathy of grade 3 or higher improved to grade 1 or lower a median of 29 days after discontinuation of nab-paclitaxel. In 2013, nab-paclitaxel in combination with gemcitabine received U.S. Food and Drug Administration (FDA) approval as first-line therapy for metastatic pancreatic cancer.

A pilot phase 1b/2 trial that added cisplatin to nab-paclitaxel and gemcitabine in treating 24 treatment-naive metastatic pancreatic adenocarcinoma patients showed impressive tumor response (complete response 8.3%, partial response 62.5%, stable disease 16.7%, progressive disease 12.5%) and extended median OS to 16.5 months.¹⁵ A phase 1b trial conducted in Europe added capecitabine to the cisplatin, nab-paclitaxel, and gemcitabine regimen, albeit with a different schedule and doses, in 24 patients with locally advanced and metastatic disease.¹⁶ This trial demonstrated an impressive overall response rate of 67%, with 43% of patients achieving a complete metabolic response on positron emission tomography scan and the CA 19-9 level decreasing by ≥ 49% in all 19 patients who had an elevated basal value. Moreover, PFS at 6 months was 96%. After chemotherapy 17 patients remained unresectable and 7 patients were taken to surgery; of the latter group, only 1 was determined to be unresectable at the time of surgery. This regimen is being explored in a larger study in patients with stage III and IV disease.

FOLFIRINOX

A randomized phase 2 clinical trial comparing FOLFIRINOX to gemcitabine monotherapy in 88 patients with treatment-naive metastatic pancreatic cancer revealed a high response rate for FOLFIRINOX (39% versus 11%, respectively) with a tolerable toxicity profile.¹⁷ FOLFIRINOX became the front-line standard of care therapy in pancreatic adenocarcinoma after the results of the subsequent phase 3 ACCORD 11 study preplanned interim analysis showed an unprecedented significantly improved OS benefit.⁶ The ACCORD 11 trial randomly assigned 342 patients with an Eastern Cooperative Oncology Group (ECOG) score of 0 or 1 and a serum bilirubin level less than 1.5 times the upper limit of normal to receive FOLFIRINOX (oxaliplatin 85 mg/m², irinotecan 180 mg/m², leucovorin 400 mg/m², and fluorouracil 400 mg/m² given as a bolus followed by 2400 mg/m² given as a 46-hour continuous infusion, every 2 weeks) or gemcitabine at a dose of 1000 mg/m² weekly for 7 of 8 weeks and then weekly for 3 of 4 weeks. The median OS in the FOLFIRINOX group was 11.1 months as compared with 6.8 months in the gemcitabine group (HR 0.57 [95% CI 0.45 to 0.73], P < 0.001). The FOLFIRINOX group also had a longer median PFS (6.4 months versus 3.3 months, HR 0.47 [95% CI 0.37 to 0.59], P < 0.001) and higher objective response rate (31.6% versus 9.4%, P < 0.001). More adverse events were noted in the FOLFIRINOX group, including grade 3 or 4 neutropenia (46% versus 21%), febrile neutropenia (5.4% versus 1.2%), thrombocytopenia (9.1% versus 3.6%), sensory neuropathy (9% versus 0%), vomiting (15% versus 8%), fatigue (23% versus 18%), and diarrhea (13% versus 2%). Despite the greater toxicity, only 31% of the FOLFIRINOX group had a definitive degradation of quality of life, as compared to 66% in the gemcitabine group (HR 0.47 [95% CI 0.30 to 0.70], P < 0.001), thus indicating an improvement in quality of life.

Of note, combinations containing irinotecan require adequate biliary function for excretion of its active glucuronide metabolite, SN-38. Approximately 10% of patients in the United States are homozygous for the UGT1A1*28 allele polymorphism, which causes increased SN-38 bioavailability and hence a potential for severe toxicities (eg, life threatening-refractory diarrhea).¹⁸ Therefore, it is recommended that physicians start with a lower dose of irinotecan or choose a different regimen altogether in such patients.

Current Approach and Future Directions

Based on results of the ACCORD 11 and MPACT trials, both front-line regimens (nab-paclitaxel/gemcitabine and FOLFIRINOX) can be considered appropriate treatment options for treatment-naive patients with good performance status who have locally advanced unresectable or metastatic pancreatic adenocarcinoma. FOLFIRINOX has a higher objective response rate than nab-paclitaxel-gemcitabine (32% versus 23%, respectively), but the adverse effect profile favors the nab-paclitaxel/gemcitabine combination, acknowledging this conclusion is limited due to lack of a comparative trial. Modifications to both regimens have been presented at American Society of Clinical Oncology symposiums, with preliminary data showing an extended median OS and a more tolerable toxicity profile.^19,20 In a recent retrospective observational cohort comparative analysis of nab-paclitaxel/gemcitabine versus FOLFIRINOX, results showed no statistical difference in median OS. The real-world data showed that gemcitabine-based therapy is being offered commonly to elderly patients and patients with poor performance status.¹³ There is no current research proposal for conducting a direct head-to-head comparison between these 2 regimens. Based on extrapolated data from the prior mentioned trials and retrospective analysis reviews, current guidelines recommend offering younger (< 65 years old), healthier (no comorbidity contraindication) patients with excellent performance status (ECOG 0) first-line FOLFIRINOX or gemcitabine/nab-paclitaxel. Elderly patients with stable comorbidities and good performance status (ECOG 1 or 2, Karnofsky performance status ≥ 70) could be preferably considered for treatment with nab-paclitaxel/gemcitabine as first-line or modified FOLFIRINOX if performance status is excellent. Patients with poor performance status (ECOG ≥ 2), advanced age, and significant comorbidities could still be considered candidates for gemcitabine monotherapy. However, there are promising indications that the combination of gemcitabine, nab-paclitaxel, and cisplatin could be a frontline therapy in advanced pancreaticobilliary malignancies in the future.

Second-Line Systemic Treatment

Case Continued

The patient and oncologist opt to begin treatment with modified FOLFIRINOX therapy, and after the patient completes 10 cycles CT scan shows progression of disease. His oncologist decides to refer the patient to a comprehensive cancer center for evaluation for participation in clinical trials, as his performance status remains very good (ECOG 1) and he would like to seek a novel therapy. His liver mass biopsy and blood liquid biopsy are sent for tumor mutational profile evaluation; results show a high tumor mutational burden and microsatellite instability.

• What are second-line treatment options for metastatic pancreatic cancer?

Second-line regimen recommendations for metastatic pancreatic cancer depend on which agents were used in first-line therapy and the patient’s performance status and comorbidities. Patients who progressed on first-line FOLFIRINOX and continue to have a good performance status (ECOG 0 or 1) may be considered for gemcitabine/nab-paclitaxel therapy; otherwise, they may be candidates for gemcitabine plus capecitabine or gemcitabine monotherapy based on performance status and goals of care. Patients who progressed on front-line gemcitabine/nab-paclitaxel may opt for FOLFIRINOX (or an oxaliplatin-based regimen [FOLFOX] or irinotecan-based regimen [FOLFIRI] if FOLFIRINOX is not tolerable), nanoliposomal irinotecan/fluorouracil/leucovorin, or a short-term infusional fluorouracil and leucovorin regimen. The preferences for second-line treatment are not well established, and patients should be encouraged to participate in clinical trials. Chemotherapy should be offered only to those patients who maintain good performance status after progression on first-line therapy. For patients with poor performance status (ECOG 3 or 4) or multiple comorbidities, a discussion about goals of care and palliative therapy is warranted.

Gemcitabine-Based Therapy

An AGEO prospective multicenter cohort assigned 57 patients with metastatic pancreatic adenocarcinoma who had disease progression on FOLFIRINOX therapy to receive gemcitabine/nab-paclitaxel (dose as per MPACT trial).²¹ The median OS was 8.8 months and median PFS was 5.1 months after FOLFIRINOX. There were reported manageable grade 3/4 toxicities in 40% of patients, which included neutropenia (12.5%), neurotoxicity (12.5%), asthenia (9%), and thrombocytopenia (6.5%). A phase 2 clinical trial that evaluated gemcitabine monotherapy in 74 patients with metastatic pancreatic cancer who had progressed on fluorouracil showed a 3.85-month survival benefit.²²

Irinotecan-Based Regimens

The NAPOLI-1 (NAnoliPOsomaL Irinotecan) trial evaluated nanoliposomal irinotecan (MM-398, nal-IRI) and fluorouracil/leucovorin in patients with metastatic pancreatic cancer refractory to gemcitabine-based therapy.²³ This global, open-label phase 3 trial initially randomly assigned and stratified 417 patients in a 1:1 fashion to receive either nanoliposomal irinotecan monotherapy (120 mg/m² every 3 weeks, equivalent to 100 mg/m² of irinotecan base) or fluorouracil/leucovorin combination. A third treatment arm consisting of nanoliposomal irinotecan (80 mg/m², equivalent to 70 mg/m² of irinotecan base) with fluorouracil and leucovorin every 2 weeks was added later in a 1:1:1 fashion. Patients assigned to nanoliposomal irinotecan plus fluorouracil/leucovorin had a significantly improved OS of 6.1 months compared to 4.2 months with fluorouracil/leucovorin (HR 0.67 [95% CI 0.49 to 0.92], P = 0.012). The results of an intention-to-treat analysis favored the nanoliposomal irinotecan regimen, with a median OS of 8.9 months compared with 5.1 months (HR 0.57, P = 0.011). In addition, median PFS was improved in the nanoliposomal irinotecan arm (3.1 months versus 1.5 months; HR 0.56, P < 0.001), and median OS did not differ between patients treated with nanoliposomal irinotecan monotherapy and those treated with fluorouracil/leucovorin (4.9 months versus 4.2 months; HR 0.99 [95% CI 0.77 to 1.28], P = 0.94). The grade 3/4 adverse events that occurred most frequently in the 117 patients assigned to nanoliposomal irinotecan plus fluorouracil/leucovorin were neutropenia (27%), diarrhea (13%), vomiting (11%), and fatigue (14%). Nanoliposomal irinotecan combination provides another second-line treatment option for patients with metastatic pancreatic adenocarcinoma who have progressed on gemcitabine-based therapy but are not candidates for FOLFIRINOX.

Oxaliplatin-Based Regimens

Regimens that combine oxaliplatin with fluorouracil and leucovorin or capecitabine have shown superiority to fluorouracil/leucovorin or best supportive care (BSC). The CONKO study group compared oxaliplatin plus fluorouracil/leucovorin to BSC as second-line therapy in patients with advanced pancreatic cancer who progressed while on gemcitabine therapy (CONKO-003).²⁴ In this phase 3 trial, patients were randomly assigned (1:1) and stratified based on duration of first-line therapy, performance status, and tumor stage to receive BSC alone or the OFF regimen, which consisted of oxaliplatin (85 mg/m² on days 8 and 22) plus short-term infusional fluorouracil (2000 mg/m² over 24 hours) and leucovorin (200 mg/m² over 30 minutes), both given on days 1, 8, 15, and 22 of a 6-week cycle. This trial was terminated early according to predefined protocol regulations because of insufficient accrual (lack of acceptance of BSC by patients and physicians). Median second-line survival was 4.82 months for patients who received OFF treatment and 2.30 months for those who received BSC (HR 0.45 [95% CI 0.24 to 0.83], P = 0.008).  Neurotoxicity (grade 1/2) and nausea, emesis, and diarrhea (grade 2/3) were worse in the chemotherapy arm; otherwise, the regimen was well tolerated.

A later modification of the CONKO-003 trial changed the comparison arm from BSC to fluorouracil/leucovorin.²⁵ The median OS in the OFF group was 5.9 months versus 3.3 months in the fluorouracil/leucovorin group (HR 0.66 [95% CI 0.48 to 0.91], log-rank P = 0.010). Time to progression was significantly extended with OFF (2.9 months) as compared with fluorouracil/leucovorin (2.0 months; HR 0.68 [95% CI 0.50 to 0.94], log-rank P = 0.019). Rates of adverse events were similar between the treatment arms, with the exception of grades 1/2 neurotoxicity, which were reported in 38.2% and 7.1% of patients in the OFF and fluorouracil/leucovorin groups, respectively (P < 0.001).

The phase 3 PANCREOX trial failed to show superiority of modified FOLFOX6 (mFOLFOX6; infusional fluorouracil, leucovorin, and oxaliplatin) over fluorouracil/leucovorin.²⁶ A phase 2 trial of oxaliplatin plus capecitabine for second-line therapy in gemcitabine-treated advanced pancreatic cancer patients with dose adjustments for performance status (ECOG 2) and age (> 65 years) showed a median OS of 5.7 months without a comparison.²⁷ A modified oxaliplatin regimen may be a reasonable second-line therapy option for gemcitabine-treated patients who are not candidates for an irinotecan-based regimen (eg, elevated bilirubin) and continue to have an acceptable performance status.

Targeted Therapies

A variety of targeted therapies have failed to demonstrate major activity in metastatic pancreatic cancer, including bevacizumab targeting vascular endothelial growth factor, cetuximab targeting epidermal growth factor receptor, ruxolitinib targeting JAK pathway signaling, saridegib targeting the hedgehog pathway, and MK-0646 targeting insulin-like growth factor 1 receptor (IGFR). Other novel agents against targetable pathways that had promising early-phase results are currently being studied in ongoing clinical trials; these include JAK-2, PI3K, MEK, and BRAF inhibitors and immunotherapy.

Recent research efforts have focused on targeted testing of advanced pancreatic cancers for mismatch repair deficiency (dMMR) and high microsatellite instability (MSI-H) and for the germline and somatic BRCA1/2 or PALB2 mutations to determine potential eligibility for immunotherapy. Patients with these tumor characteristics and/or mutations might also be more sensitive to platinum-based chemotherapy agents or poly (ADP-ribose) polymerase (PARP) inhibitors. Germline mutations in BRCA 1/2 are present in 5% to 8% of patients with pancreatic cancer (up to 10%–15% in Ashkenazi Jewish population).²⁸ A superior median OS was retrospectively observed for patients with advanced stage BRCA 1/2-associated pancreatic adenocarcinoma who were treated with platinum-based chemotherapy agents versus those treated with non-platinum-based agents (22 versus 9 months; P = 0.039).²² PARP inhibitors have shown activity in germline BRCA1/2-associated breast (off label) and ovarian cancers (approved by the FDA). The efficacy and safety of PARP inhibitors were evaluated in a phase 2 study of a spectrum of BRCA1/2-associated cancers, including pancreatic cancer. The results revealed a tumor response rate of 21.7% (5 of 23 patients with pancreatic cancer [95% CI 7.5 to 43.7]), and 35% of patients had stable disease for a duration of 8 weeks or more (95% CI 16.4 to 57.3) with good tolerability.²⁹ Three novel PARP inhibitors are currently under clinical trial investigation in patients with germline BRCA 1/2- and PALB2-mutated metastatic pancreatic cancer: maintenance olaparib (NCT02184195) and rucaparib (NCT03140670) are both being studied as monotherapy in patients whose disease has not progressed on first-line platinum-based chemotherapy, and veliparib is being evaluated in a 3-arm study that includes gemcitabine and cisplatin with or without veliparib and single-agent maintenance veliparib (NCT01585805).

In 2017, the FDA granted accelerated approval to pembrolizumab for treatment of patients with unresectable or metastatic MSI-H or dMMR solid tumors whose disease progressed on prior treatments, making it the first oncology drug to be approved based on the genetic features of the tumor rather than its location in the body. This first tissue/site-agnostic approval was based on results from 5 single-arm trials involving 149 patients, including 5 patients with pancreatic cancer.³⁰ The objective response rate with pembrolizumab was 39.6% (95% CI 31.7 to 47.9), including a 7.4% complete response rate and a 32.2% partial response rate. The median duration of response was not reached at the time of publication (range, 1.6+ months to 22.7+ months).

Palliative and Supportive Care

Case Continued

The patient opts to participate in a novel immunotherapy clinical trial and is currently on his second cycle. He continues to have right upper quadrant pain despite opioid analgesia, has not gained any weight, and noticed new right lower extremity swelling after a recent holiday vacation to Florida.

• What supportive measures should be in place for patients with metastatic adenocarcinoma?

Most patients with advanced pancreatic adenocarcinoma will require a palliative intervention. All new unresectable pancreatic cancer patients should have an early psychosocial evaluation; identification of symptoms and implementation of preventive interventions that would improve quality of life and reduce suffering are paramount. A multidisciplinary team including physician/nursing staff, nutritionist/dietitian, palliative service, a social worker, and a case manager should be involved in patient care. More than two-thirds of patients can develop symptomatic biliary obstruction.³¹ Bile duct obstruction due to locally advanced pancreatic adenocarcinoma causes hyperbilirubinemia, which requires endoscopic placement of a metallic or plastic stent; plastic stents have a higher rate of re-occlusion.³² Appropriate bile flow allows treatment with irinotecan-based regimens. Percutaneous biliary drainage may be necessary if endoscopic intervention is not feasible.

Approximately one quarter of patients may present with gastric outlet obstruction due to duodenal obstruction.³¹ Endoscopic placement of an enteral expandable metal stent is preferred. Alternatively, percutaneous endoscopic gastrostomy tube placement may give symptomatic relief. Palliative surgical interventions are reserved for patients with greater life expectancy and in whom all other interventions have failed or are not feasible.

Almost all patients with pancreatic adenocarcinoma will experience cancer-associated pain. Intractable pain should be treated with a celiac plexus block. Radiation therapy may be considered as an adjunct therapy for pain, bleeding, and/or local obstruction. The National Comprehensive Cancer Network guidelines recommend that patients who undergo a laparotomy for potentially resectable disease but are found to have unresectable disease at the time of surgery should undergo stenting, open biliary-enteric bypass with or without gastrojejunostomy, and/or celiac plexus neurolysis.³³

Pancreatic exocrine enzyme insufficiency due to tumor extension, duct blockage, or surgical removal may cause malabsoprtive steatorrhea, contributing to cancer cachexia syndrome. Nutritional evaluation and daily oral pancreatic enzyme supplementation are recommended.³⁴

Patients diagnosed with pancreatic adenocarcinoma have a venous thromboembolism (VTE) incidence of 20 per 100 person-years (5%–60% of patients) and are considered at very high risk for VTE based on the Khorana score.³⁵ The preferred VTE treatment is low-molecular-weight heparin rather than warfarin based on the results of the CLOT study.³⁶ There is no current evidence for routine prophylactic therapy or the use of direct oral anticoagulants.

Finally, a cancer diagnosis, particularly pancreatic cancer, causes a significant amount of psychosocial stress and requires active support and counseling from a professional.

Conclusion

Pancreatic adenocarcinoma is the most lethal of all the gastrointestinal malignancies. FOLFIRINOX and gemcitabine/nab-paclitaxel are superior to gemcitabine monotherapy for patients with advanced unresectable and/or metastatic pancreatic cancer who are candidates for more aggressive therapy and are considered first-line therapies. Early data on the gemcitabine, nab-paclitaxel, and cisplatin combination appears to show superior efficacy. Second-line therapies are selected based on the patient’s performance status, first-line regimen, and residual toxicities from the prior regimen; options include gemcitabine/nab-paclitaxel, FOLFIRINOX (± oxaliplatin or irinotecan), single-agent gemcitabine (elderly frail patients), fluorouracil and liposomal-irinotecan, or referral for a clinical trial. The main challenge with pancreatic cancer is the development of stroma around the tumor, which abrogates drug delivery, allows for tumor growth in a hypoxic microenvironment, alters the metabolomics, and causes an immunosuppressive microenvironment. Drugs that target the microenvironments, such as hedgehog pathway inhibitors, have failed to show any clinical benefit, and we hope to see more efficacious microenvironment-targeted novel drugs in the future. In addition, immunotherapy has not shown any significant efficacy in clinical trials and many trials are still ongoing.

Introduction

Pancreatic ductal adenocarcinoma is a challenging disease with a poor prognosis, with 5-year survival rates in the single digits (~8%).¹ Survival rates in pancreatic cancer are low in part because most patients have advanced disease at the time of diagnosis and early development of systemic metastatic disease is common, with approximately 52% of patients with newly diagnosed pancreatic cancer having metastatic disease at diagnosis.¹ Surgical resection with negative margins is the cornerstone of potentially curative therapy for localized disease, but only 15% to 20% of patients are eligible for resection at the time of initial diagnosis. Patients with unresectable and metastatic disease are offered palliative chemotherapy. Unfortunately, early recurrence is common in patients with resectable tumors who achieve a complete resection and are treated with adjuvant therapy (5-year recurrence rate ~80%).^2,3 This article reviews the management of patients with unresectable and/or metastatic pancreatic cancer. A previous article reviewed the diagnosis and staging of pancreatic cancer and the approach to neoadjuvant and adjuvant therapy in patients with resectable and borderline-resectable disease.⁴

First-Line Systemic Treatment

Case Presentation

A 72-year-old man who underwent treatment for pancreatic adenocarcinoma 18 months ago presents to the emergency department after developing poor appetite, weight loss, and abdominal discomfort and fullness without diarrhea, which has been constant for the past 2 weeks even though he has been taking analgesics and pancreatic enzymes.

The patient was diagnosed with pancreatic cancer 18 months ago after presenting with yellowish skin and sclera color; abdominal and pelvis computed tomography (CT) with intravenous contrast showed a pancreatic head mass measuring 2.6 × 2.3 cm minimally abutting the anterior surface of the superior mesenteric vein. Endoscopic ultrasound confirmed an irregular mass at the head of the pancreas and sonographic evidence suggested invasion into the portal vein. Examination of a tissue sample obtained during the procedure showed that the mass was consistent with pancreatic adenocarcinoma. Magnetic resonance imaging (MRI) performed to define venous vasculature involvement revealed a pancreatic head mass measuring 3.0 × 2.7 cm without arterial or venous vasculature invasion. The mass was abutting the portal vein and superior mesenteric veins, and a nonspecific 8-mm aortocaval lymph node was noted. The tumor was deemed to be borderline resectable, and the patient received neoadjuvant therapy with gemcitabine and nab-paclitaxel. After 4 cycles, his carbohydrate antigen (CA) 19-9 level decreased, and MRI revealed a smaller head mass (1.3 × 1.4 cm) with stable effacement of the superior mesenteric vein and no portal vein involvement; the aortocaval lymph node remained stable. He was treated with gemcitabine chemoradiotherapy prior to undergoing an uncomplicated partial pancreaticoduodenectomy. Analysis of a surgical pathology specimen revealed T3N0 disease with a closest margin of 0.1 cm. Postsurgery, the patient completed 4 cycles of adjuvant chemotherapy with gemcitabine plus capecitabine.

At his current presentation, MRI of the abdomen and pelvis reveals a new liver mass and peritoneal thickness. Serology testing reveals a CA 19-9 level of 240 U/mL, and other liver function tests are within normal limits. Biopsy of the mass confirms recurrence.

• What systemic chemotherapy would you recommend for this patient with metastatic pancreatic adenocarcinoma?

Most cases of pancreatic cancer are unresectable and/or metastatic at the time of diagnosis. Identifying treatment endpoints and the patient’s goals of care is a critical step in management. Systemic chemotherapy can provide significant survival benefit in first-line and second-line treatment compared to best supportive care. Palliative interventions also include systemic therapy, which often improves pain control and other cancer related–symptoms and hence quality of life. Participation in clinical trials should be offered to all patients. Therapy selection depends on the patient’s performance status, comorbidities, and liver profile and the results of biomarker testing and mutation analysis.

Several single-agents, including fluoropyrimidines, gemcitabine, irinotecan, platinum compounds, and taxanes, have minor objective response rates (< 10%) and a minimal survival benefit (~2 weeks) in metastatic pancreatic adenocarcinoma. Conversely, multi-agent therapies provide higher response rates and can extend overall survival (OS). Two combinations, nab-paclitaxel plus gemcitabine and FOLFIRINOX (oxaliplatin, irinotecan, leucovorin, and flourouracil), have significantly prolonged survival compared to best single-agent gemcitabine, as demonstrated in the MPACT (Metastatic Pancreatic Adenocarcinoma Clinical Trial) and PRODIGE 4/ACCORD 11 trials.^5,6 Because both multi-agent regimens are also associated with a more toxic adverse effect profile, gemcitabine monotherapy continues to be a front-line therapy for patients with multiple comorbidities, elderly frail patients (> 80 years of age), or patients who cannot tolerate other combinations.⁷

Gemcitabine-Based Therapy

Gemcitabine became a standard of care treatment for pancreatic cancer in the mid-1990s, and was tested as a second-line therapy in a multicenter phase 2 clinical trial that accrued 74 patients with metastatic pancreatic cancer who had progressed on fluorouracil therapy. In this trial, 27% of patients treated with gemcitabine achieved a clinical benefit response and the median OS was 3.85 months.⁸ The agent was generally well-tolerated with a low incidence of grade 3 or 4 toxicities. Subsequently, a randomized clinical trial compared gemcitabine to fluorouracil in the front-line setting in 126 patients with newly diagnosed advanced pancreatic cancer.⁹ Patients were randomly assigned to receive single-agent intravenous fluorouracil administered without leucovorin as a short-term infusion (600 mg/m² once weekly) or gemcitabine (1000 mg/m² weekly for up to 7 weeks followed by 1 week of rest, and then weekly for 3 out of every 4 weeks thereafter). A higher proportion of patients treated with gemcitabine had a clinical benefit response (23.8% versus 4.8%), with an improvement in a composite measure of pain (pain intensity and analgesic consumption) and performance status. Clinical responses assessed by a secondary measure, weight gain, were below 10% in both arms, but the median OS was significantly longer for the gemcitabine arm (5.65 months versus 4.4 months, P = 0.0025) and the 1-year OS rate also favored the gemcitabine arm (18% versus 2%). Grade 3/4 neutropenia was reported more frequently in the gemcitabine arm (23% versus 5%). There is no evidence that increasing the dose intensity of the fixed-dose rate of gemcitabine (1000 mg/m² per week administered as a 30-minute infusion) leads to improved antitumor activity.

Following publication of the trial conducted by Burris and colleagues,⁹ a plethora of clinical trials have tried to outperform gemcitabine monotherapy, with all trials studying gemcitabine monotherapy compared with gemcitabine plus another agent (fluorouracil, cisplatin, oxaliplatin, irinotecan, pemetrexed, novel biologics including cetuximab, bevacizumab, axitinib, sorafenib, aflibercept). These combinations have failed to significantly extend OS compared to single-agent gemcitabine, although some showed a marginal clinical benefit:

• Capecitabine¹⁰ (hazard ratio [HR] 0.86 [95% confidence interval {CI} 0.75 to 0.98])
• Erlotinib¹¹ (HR 0.81 [95% CI 0.69 to 0.99])
• Cisplatin, epirubicin, fluorouracil, gemcitabine¹² (HR 0.65 [95% CI 0.43 to 0.99])

The best outcomes were obtained with gemcitabine plus nab-paclitaxel compared to gemcitabine monotherapy. The gemcitabine/nab-paclitaxel combination has not been compared to FOLFIRINOX in the front-line setting, as the ACCORD 11 and MPACT trials were ongoing simultaneously. However, a large retrospective trial that compared use of the regimens in the US Oncology Network in the United States demonstrated similar efficacy, although more patients treated with FOLFIRINOX needed white blood cell growth factor administration.¹³

Gemcitabine/nab-paclitaxel was studied in a phase 1/2 clinical trial with 67 untreated metastatic pancreatic cancer patients.¹⁴ Patients received nab-paclitaxel at doses of 100, 125, or 150 mg/m² followed by gemcitabine 1000 mg/m² on days 1, 8, and 15 every 28 days. The maximum tolerated dose (MTD) was 1000 mg/m² of gemcitabine plus 125 mg/m² of nab-paclitaxel once a week for 3 weeks every 28 days. Dose-limiting toxicities were sepsis and neutropenia. Patients who received the MTD had a response rate of 48%, median OS of 12.2 months, and a 1-year survival rate of 48%.

The landmark phase 3 MPACT trial confirmed that adding nab-paclitaxel to gemcitabine prolongs survival compared with gemcitabine monotherapy.⁵ This multinational randomized study included 861 treatment-naive patients with a Karnofsky performance score of 70 or higher. The median OS in the nab-paclitaxel/gemcitabine group was 8.5 months, as compared to 6.7 months in the gemcitabine monotherapy group (HR for death 0.72 [95% CI 0.62 to 0.83], P < 0.001). The survival rate was 35% in the nab-paclitaxel/gemcitabine group versus 22% in the gemcitabine group at 1 year, and 9% versus 4% at 2 years. Median progression-free survival (PFS) was 5.5 months in the nab-paclitaxel/gemcitabine group, compared to 3.7 months in the gemcitabine group (HR for disease progression or death 0.69 [95% CI 0.58 to 0.82], P < 0.001). The overall response rate according to independent review was 23% compared with 7% in the 2 groups, respectively (P < 0.001). The most common adverse events of grade 3 or higher were neutropenia (38% in the nab-paclitaxel/gemcitabine group versus 27% in the gemcitabine group), fatigue (17% versus 7%), and neuropathy (17% versus 1%). Febrile neutropenia occurred in 3% of the combination group versus 1% of the montherapy group. In the nab-paclitaxel/gemcitabine group, neuropathy of grade 3 or higher improved to grade 1 or lower a median of 29 days after discontinuation of nab-paclitaxel. In 2013, nab-paclitaxel in combination with gemcitabine received U.S. Food and Drug Administration (FDA) approval as first-line therapy for metastatic pancreatic cancer.

A pilot phase 1b/2 trial that added cisplatin to nab-paclitaxel and gemcitabine in treating 24 treatment-naive metastatic pancreatic adenocarcinoma patients showed impressive tumor response (complete response 8.3%, partial response 62.5%, stable disease 16.7%, progressive disease 12.5%) and extended median OS to 16.5 months.¹⁵ A phase 1b trial conducted in Europe added capecitabine to the cisplatin, nab-paclitaxel, and gemcitabine regimen, albeit with a different schedule and doses, in 24 patients with locally advanced and metastatic disease.¹⁶ This trial demonstrated an impressive overall response rate of 67%, with 43% of patients achieving a complete metabolic response on positron emission tomography scan and the CA 19-9 level decreasing by ≥ 49% in all 19 patients who had an elevated basal value. Moreover, PFS at 6 months was 96%. After chemotherapy 17 patients remained unresectable and 7 patients were taken to surgery; of the latter group, only 1 was determined to be unresectable at the time of surgery. This regimen is being explored in a larger study in patients with stage III and IV disease.

FOLFIRINOX

A randomized phase 2 clinical trial comparing FOLFIRINOX to gemcitabine monotherapy in 88 patients with treatment-naive metastatic pancreatic cancer revealed a high response rate for FOLFIRINOX (39% versus 11%, respectively) with a tolerable toxicity profile.¹⁷ FOLFIRINOX became the front-line standard of care therapy in pancreatic adenocarcinoma after the results of the subsequent phase 3 ACCORD 11 study preplanned interim analysis showed an unprecedented significantly improved OS benefit.⁶ The ACCORD 11 trial randomly assigned 342 patients with an Eastern Cooperative Oncology Group (ECOG) score of 0 or 1 and a serum bilirubin level less than 1.5 times the upper limit of normal to receive FOLFIRINOX (oxaliplatin 85 mg/m², irinotecan 180 mg/m², leucovorin 400 mg/m², and fluorouracil 400 mg/m² given as a bolus followed by 2400 mg/m² given as a 46-hour continuous infusion, every 2 weeks) or gemcitabine at a dose of 1000 mg/m² weekly for 7 of 8 weeks and then weekly for 3 of 4 weeks. The median OS in the FOLFIRINOX group was 11.1 months as compared with 6.8 months in the gemcitabine group (HR 0.57 [95% CI 0.45 to 0.73], P < 0.001). The FOLFIRINOX group also had a longer median PFS (6.4 months versus 3.3 months, HR 0.47 [95% CI 0.37 to 0.59], P < 0.001) and higher objective response rate (31.6% versus 9.4%, P < 0.001). More adverse events were noted in the FOLFIRINOX group, including grade 3 or 4 neutropenia (46% versus 21%), febrile neutropenia (5.4% versus 1.2%), thrombocytopenia (9.1% versus 3.6%), sensory neuropathy (9% versus 0%), vomiting (15% versus 8%), fatigue (23% versus 18%), and diarrhea (13% versus 2%). Despite the greater toxicity, only 31% of the FOLFIRINOX group had a definitive degradation of quality of life, as compared to 66% in the gemcitabine group (HR 0.47 [95% CI 0.30 to 0.70], P < 0.001), thus indicating an improvement in quality of life.

Of note, combinations containing irinotecan require adequate biliary function for excretion of its active glucuronide metabolite, SN-38. Approximately 10% of patients in the United States are homozygous for the UGT1A1*28 allele polymorphism, which causes increased SN-38 bioavailability and hence a potential for severe toxicities (eg, life threatening-refractory diarrhea).¹⁸ Therefore, it is recommended that physicians start with a lower dose of irinotecan or choose a different regimen altogether in such patients.

Current Approach and Future Directions

Based on results of the ACCORD 11 and MPACT trials, both front-line regimens (nab-paclitaxel/gemcitabine and FOLFIRINOX) can be considered appropriate treatment options for treatment-naive patients with good performance status who have locally advanced unresectable or metastatic pancreatic adenocarcinoma. FOLFIRINOX has a higher objective response rate than nab-paclitaxel-gemcitabine (32% versus 23%, respectively), but the adverse effect profile favors the nab-paclitaxel/gemcitabine combination, acknowledging this conclusion is limited due to lack of a comparative trial. Modifications to both regimens have been presented at American Society of Clinical Oncology symposiums, with preliminary data showing an extended median OS and a more tolerable toxicity profile.^19,20 In a recent retrospective observational cohort comparative analysis of nab-paclitaxel/gemcitabine versus FOLFIRINOX, results showed no statistical difference in median OS. The real-world data showed that gemcitabine-based therapy is being offered commonly to elderly patients and patients with poor performance status.¹³ There is no current research proposal for conducting a direct head-to-head comparison between these 2 regimens. Based on extrapolated data from the prior mentioned trials and retrospective analysis reviews, current guidelines recommend offering younger (< 65 years old), healthier (no comorbidity contraindication) patients with excellent performance status (ECOG 0) first-line FOLFIRINOX or gemcitabine/nab-paclitaxel. Elderly patients with stable comorbidities and good performance status (ECOG 1 or 2, Karnofsky performance status ≥ 70) could be preferably considered for treatment with nab-paclitaxel/gemcitabine as first-line or modified FOLFIRINOX if performance status is excellent. Patients with poor performance status (ECOG ≥ 2), advanced age, and significant comorbidities could still be considered candidates for gemcitabine monotherapy. However, there are promising indications that the combination of gemcitabine, nab-paclitaxel, and cisplatin could be a frontline therapy in advanced pancreaticobilliary malignancies in the future.

Second-Line Systemic Treatment

Case Continued

The patient and oncologist opt to begin treatment with modified FOLFIRINOX therapy, and after the patient completes 10 cycles CT scan shows progression of disease. His oncologist decides to refer the patient to a comprehensive cancer center for evaluation for participation in clinical trials, as his performance status remains very good (ECOG 1) and he would like to seek a novel therapy. His liver mass biopsy and blood liquid biopsy are sent for tumor mutational profile evaluation; results show a high tumor mutational burden and microsatellite instability.

• What are second-line treatment options for metastatic pancreatic cancer?

Second-line regimen recommendations for metastatic pancreatic cancer depend on which agents were used in first-line therapy and the patient’s performance status and comorbidities. Patients who progressed on first-line FOLFIRINOX and continue to have a good performance status (ECOG 0 or 1) may be considered for gemcitabine/nab-paclitaxel therapy; otherwise, they may be candidates for gemcitabine plus capecitabine or gemcitabine monotherapy based on performance status and goals of care. Patients who progressed on front-line gemcitabine/nab-paclitaxel may opt for FOLFIRINOX (or an oxaliplatin-based regimen [FOLFOX] or irinotecan-based regimen [FOLFIRI] if FOLFIRINOX is not tolerable), nanoliposomal irinotecan/fluorouracil/leucovorin, or a short-term infusional fluorouracil and leucovorin regimen. The preferences for second-line treatment are not well established, and patients should be encouraged to participate in clinical trials. Chemotherapy should be offered only to those patients who maintain good performance status after progression on first-line therapy. For patients with poor performance status (ECOG 3 or 4) or multiple comorbidities, a discussion about goals of care and palliative therapy is warranted.

Gemcitabine-Based Therapy

An AGEO prospective multicenter cohort assigned 57 patients with metastatic pancreatic adenocarcinoma who had disease progression on FOLFIRINOX therapy to receive gemcitabine/nab-paclitaxel (dose as per MPACT trial).²¹ The median OS was 8.8 months and median PFS was 5.1 months after FOLFIRINOX. There were reported manageable grade 3/4 toxicities in 40% of patients, which included neutropenia (12.5%), neurotoxicity (12.5%), asthenia (9%), and thrombocytopenia (6.5%). A phase 2 clinical trial that evaluated gemcitabine monotherapy in 74 patients with metastatic pancreatic cancer who had progressed on fluorouracil showed a 3.85-month survival benefit.²²

Irinotecan-Based Regimens

The NAPOLI-1 (NAnoliPOsomaL Irinotecan) trial evaluated nanoliposomal irinotecan (MM-398, nal-IRI) and fluorouracil/leucovorin in patients with metastatic pancreatic cancer refractory to gemcitabine-based therapy.²³ This global, open-label phase 3 trial initially randomly assigned and stratified 417 patients in a 1:1 fashion to receive either nanoliposomal irinotecan monotherapy (120 mg/m² every 3 weeks, equivalent to 100 mg/m² of irinotecan base) or fluorouracil/leucovorin combination. A third treatment arm consisting of nanoliposomal irinotecan (80 mg/m², equivalent to 70 mg/m² of irinotecan base) with fluorouracil and leucovorin every 2 weeks was added later in a 1:1:1 fashion. Patients assigned to nanoliposomal irinotecan plus fluorouracil/leucovorin had a significantly improved OS of 6.1 months compared to 4.2 months with fluorouracil/leucovorin (HR 0.67 [95% CI 0.49 to 0.92], P = 0.012). The results of an intention-to-treat analysis favored the nanoliposomal irinotecan regimen, with a median OS of 8.9 months compared with 5.1 months (HR 0.57, P = 0.011). In addition, median PFS was improved in the nanoliposomal irinotecan arm (3.1 months versus 1.5 months; HR 0.56, P < 0.001), and median OS did not differ between patients treated with nanoliposomal irinotecan monotherapy and those treated with fluorouracil/leucovorin (4.9 months versus 4.2 months; HR 0.99 [95% CI 0.77 to 1.28], P = 0.94). The grade 3/4 adverse events that occurred most frequently in the 117 patients assigned to nanoliposomal irinotecan plus fluorouracil/leucovorin were neutropenia (27%), diarrhea (13%), vomiting (11%), and fatigue (14%). Nanoliposomal irinotecan combination provides another second-line treatment option for patients with metastatic pancreatic adenocarcinoma who have progressed on gemcitabine-based therapy but are not candidates for FOLFIRINOX.

Oxaliplatin-Based Regimens

Regimens that combine oxaliplatin with fluorouracil and leucovorin or capecitabine have shown superiority to fluorouracil/leucovorin or best supportive care (BSC). The CONKO study group compared oxaliplatin plus fluorouracil/leucovorin to BSC as second-line therapy in patients with advanced pancreatic cancer who progressed while on gemcitabine therapy (CONKO-003).²⁴ In this phase 3 trial, patients were randomly assigned (1:1) and stratified based on duration of first-line therapy, performance status, and tumor stage to receive BSC alone or the OFF regimen, which consisted of oxaliplatin (85 mg/m² on days 8 and 22) plus short-term infusional fluorouracil (2000 mg/m² over 24 hours) and leucovorin (200 mg/m² over 30 minutes), both given on days 1, 8, 15, and 22 of a 6-week cycle. This trial was terminated early according to predefined protocol regulations because of insufficient accrual (lack of acceptance of BSC by patients and physicians). Median second-line survival was 4.82 months for patients who received OFF treatment and 2.30 months for those who received BSC (HR 0.45 [95% CI 0.24 to 0.83], P = 0.008).  Neurotoxicity (grade 1/2) and nausea, emesis, and diarrhea (grade 2/3) were worse in the chemotherapy arm; otherwise, the regimen was well tolerated.

A later modification of the CONKO-003 trial changed the comparison arm from BSC to fluorouracil/leucovorin.²⁵ The median OS in the OFF group was 5.9 months versus 3.3 months in the fluorouracil/leucovorin group (HR 0.66 [95% CI 0.48 to 0.91], log-rank P = 0.010). Time to progression was significantly extended with OFF (2.9 months) as compared with fluorouracil/leucovorin (2.0 months; HR 0.68 [95% CI 0.50 to 0.94], log-rank P = 0.019). Rates of adverse events were similar between the treatment arms, with the exception of grades 1/2 neurotoxicity, which were reported in 38.2% and 7.1% of patients in the OFF and fluorouracil/leucovorin groups, respectively (P < 0.001).

The phase 3 PANCREOX trial failed to show superiority of modified FOLFOX6 (mFOLFOX6; infusional fluorouracil, leucovorin, and oxaliplatin) over fluorouracil/leucovorin.²⁶ A phase 2 trial of oxaliplatin plus capecitabine for second-line therapy in gemcitabine-treated advanced pancreatic cancer patients with dose adjustments for performance status (ECOG 2) and age (> 65 years) showed a median OS of 5.7 months without a comparison.²⁷ A modified oxaliplatin regimen may be a reasonable second-line therapy option for gemcitabine-treated patients who are not candidates for an irinotecan-based regimen (eg, elevated bilirubin) and continue to have an acceptable performance status.

Targeted Therapies

A variety of targeted therapies have failed to demonstrate major activity in metastatic pancreatic cancer, including bevacizumab targeting vascular endothelial growth factor, cetuximab targeting epidermal growth factor receptor, ruxolitinib targeting JAK pathway signaling, saridegib targeting the hedgehog pathway, and MK-0646 targeting insulin-like growth factor 1 receptor (IGFR). Other novel agents against targetable pathways that had promising early-phase results are currently being studied in ongoing clinical trials; these include JAK-2, PI3K, MEK, and BRAF inhibitors and immunotherapy.

Recent research efforts have focused on targeted testing of advanced pancreatic cancers for mismatch repair deficiency (dMMR) and high microsatellite instability (MSI-H) and for the germline and somatic BRCA1/2 or PALB2 mutations to determine potential eligibility for immunotherapy. Patients with these tumor characteristics and/or mutations might also be more sensitive to platinum-based chemotherapy agents or poly (ADP-ribose) polymerase (PARP) inhibitors. Germline mutations in BRCA 1/2 are present in 5% to 8% of patients with pancreatic cancer (up to 10%–15% in Ashkenazi Jewish population).²⁸ A superior median OS was retrospectively observed for patients with advanced stage BRCA 1/2-associated pancreatic adenocarcinoma who were treated with platinum-based chemotherapy agents versus those treated with non-platinum-based agents (22 versus 9 months; P = 0.039).²² PARP inhibitors have shown activity in germline BRCA1/2-associated breast (off label) and ovarian cancers (approved by the FDA). The efficacy and safety of PARP inhibitors were evaluated in a phase 2 study of a spectrum of BRCA1/2-associated cancers, including pancreatic cancer. The results revealed a tumor response rate of 21.7% (5 of 23 patients with pancreatic cancer [95% CI 7.5 to 43.7]), and 35% of patients had stable disease for a duration of 8 weeks or more (95% CI 16.4 to 57.3) with good tolerability.²⁹ Three novel PARP inhibitors are currently under clinical trial investigation in patients with germline BRCA 1/2- and PALB2-mutated metastatic pancreatic cancer: maintenance olaparib (NCT02184195) and rucaparib (NCT03140670) are both being studied as monotherapy in patients whose disease has not progressed on first-line platinum-based chemotherapy, and veliparib is being evaluated in a 3-arm study that includes gemcitabine and cisplatin with or without veliparib and single-agent maintenance veliparib (NCT01585805).

In 2017, the FDA granted accelerated approval to pembrolizumab for treatment of patients with unresectable or metastatic MSI-H or dMMR solid tumors whose disease progressed on prior treatments, making it the first oncology drug to be approved based on the genetic features of the tumor rather than its location in the body. This first tissue/site-agnostic approval was based on results from 5 single-arm trials involving 149 patients, including 5 patients with pancreatic cancer.³⁰ The objective response rate with pembrolizumab was 39.6% (95% CI 31.7 to 47.9), including a 7.4% complete response rate and a 32.2% partial response rate. The median duration of response was not reached at the time of publication (range, 1.6+ months to 22.7+ months).

Palliative and Supportive Care

Case Continued

The patient opts to participate in a novel immunotherapy clinical trial and is currently on his second cycle. He continues to have right upper quadrant pain despite opioid analgesia, has not gained any weight, and noticed new right lower extremity swelling after a recent holiday vacation to Florida.

• What supportive measures should be in place for patients with metastatic adenocarcinoma?

Most patients with advanced pancreatic adenocarcinoma will require a palliative intervention. All new unresectable pancreatic cancer patients should have an early psychosocial evaluation; identification of symptoms and implementation of preventive interventions that would improve quality of life and reduce suffering are paramount. A multidisciplinary team including physician/nursing staff, nutritionist/dietitian, palliative service, a social worker, and a case manager should be involved in patient care. More than two-thirds of patients can develop symptomatic biliary obstruction.³¹ Bile duct obstruction due to locally advanced pancreatic adenocarcinoma causes hyperbilirubinemia, which requires endoscopic placement of a metallic or plastic stent; plastic stents have a higher rate of re-occlusion.³² Appropriate bile flow allows treatment with irinotecan-based regimens. Percutaneous biliary drainage may be necessary if endoscopic intervention is not feasible.

Approximately one quarter of patients may present with gastric outlet obstruction due to duodenal obstruction.³¹ Endoscopic placement of an enteral expandable metal stent is preferred. Alternatively, percutaneous endoscopic gastrostomy tube placement may give symptomatic relief. Palliative surgical interventions are reserved for patients with greater life expectancy and in whom all other interventions have failed or are not feasible.

Almost all patients with pancreatic adenocarcinoma will experience cancer-associated pain. Intractable pain should be treated with a celiac plexus block. Radiation therapy may be considered as an adjunct therapy for pain, bleeding, and/or local obstruction. The National Comprehensive Cancer Network guidelines recommend that patients who undergo a laparotomy for potentially resectable disease but are found to have unresectable disease at the time of surgery should undergo stenting, open biliary-enteric bypass with or without gastrojejunostomy, and/or celiac plexus neurolysis.³³

Pancreatic exocrine enzyme insufficiency due to tumor extension, duct blockage, or surgical removal may cause malabsoprtive steatorrhea, contributing to cancer cachexia syndrome. Nutritional evaluation and daily oral pancreatic enzyme supplementation are recommended.³⁴

Patients diagnosed with pancreatic adenocarcinoma have a venous thromboembolism (VTE) incidence of 20 per 100 person-years (5%–60% of patients) and are considered at very high risk for VTE based on the Khorana score.³⁵ The preferred VTE treatment is low-molecular-weight heparin rather than warfarin based on the results of the CLOT study.³⁶ There is no current evidence for routine prophylactic therapy or the use of direct oral anticoagulants.

Finally, a cancer diagnosis, particularly pancreatic cancer, causes a significant amount of psychosocial stress and requires active support and counseling from a professional.

Conclusion

Pancreatic adenocarcinoma is the most lethal of all the gastrointestinal malignancies. FOLFIRINOX and gemcitabine/nab-paclitaxel are superior to gemcitabine monotherapy for patients with advanced unresectable and/or metastatic pancreatic cancer who are candidates for more aggressive therapy and are considered first-line therapies. Early data on the gemcitabine, nab-paclitaxel, and cisplatin combination appears to show superior efficacy. Second-line therapies are selected based on the patient’s performance status, first-line regimen, and residual toxicities from the prior regimen; options include gemcitabine/nab-paclitaxel, FOLFIRINOX (± oxaliplatin or irinotecan), single-agent gemcitabine (elderly frail patients), fluorouracil and liposomal-irinotecan, or referral for a clinical trial. The main challenge with pancreatic cancer is the development of stroma around the tumor, which abrogates drug delivery, allows for tumor growth in a hypoxic microenvironment, alters the metabolomics, and causes an immunosuppressive microenvironment. Drugs that target the microenvironments, such as hedgehog pathway inhibitors, have failed to show any clinical benefit, and we hope to see more efficacious microenvironment-targeted novel drugs in the future. In addition, immunotherapy has not shown any significant efficacy in clinical trials and many trials are still ongoing.

Introduction

Non-Hodgkin lymphoma (NHL) comprises a wide variety of malignant hematologic disorders with varying clinical and biological features. The more than 60 separate NHL subtypes can be classified according to cell of origin (B cell versus T cell), anatomical location (eg, orbital, testicular, bone, central nervous system), clinical behavior (indolent versus aggressive), histological features, or cytogenetic abnormalities. Although various NHL classification schemes have been used over the years, the World Health Organization (WHO) classification is now widely accepted as the definitive pathologic classification system for lymphoproliferative disorders, incorporating morphologic, immunohistochemical, flow cytometric, cytogenetic, and molecular features.¹ While the pathologic and molecular subclassification of NHL has become increasingly refined in recent years, from a management standpoint, classification based on clinical behavior remains very useful. This approach separates NHL subtypes into indolent versus aggressive categories. Whereas indolent NHLs may remain clinically insignificant for months to years, aggressive B-cell NHLs generally become life-threatening within weeks to months without treatment.

Epidemiology

Data from cancer registries show a steady, unexplainable increase in the incidence of NHL during the second half of the 20th century; the incidence has subsequently plateaued. There was a significant increase in NHL incidence between 1970 and 1995, which has been attributed in part to the HIV epidemic. More than 72,000 new cases of NHL were diagnosed in the United States in 2017, compared to just over 8000 cases of Hodgkin lymphoma, making NHL the sixth most common cancer in adult men and the fifth most common in adult women.² NHL appears to occur more frequently in Western countries than in Asian populations.

Various factors associated with increased risk for B-cell NHL have been identified over the years, including occupational and environmental exposure to certain pesticides and herbicides,³ immunosuppression associated with HIV infection,⁴ autoimmune disorders,⁵ iatrogenically induced immune suppression in the post-transplant and other settings,⁶ family history of NHL,⁷ and a personal history of a prior cancer, including Hodgkin lymphoma and prior NHL.⁸ In terms of infectious agents associated with aggressive B-cell NHLs, Epstein-Barr virus (EBV) has a clear pathogenic role in Burkitt lymphoma, in many cases of post-transplant lymphoproliferative disorders, and in some cases of HIV-related aggressive B-cell lymphoma.⁹ Human herpesvirus-8 viral genomes have been found in virtually all cases of primary effusion lymphomas.¹⁰ Epidemiological studies also have linked hepatitis B and C to increased incidences of certain NHL subtypes,^11–13 including primary hepatic diffuse large B-cell lymphoma (DLBCL). Similarly, Helicobacter pylori has been associated with gastric DLBCL.

Staging and Work-Up

A tissue biopsy is essential in the diagnosis and management of NHL. The most significant disadvantage of fine-needle aspiration cytology is the lack of histologic architecture. The optimal specimen is an excisional biopsy; when this cannot be performed, a core needle biopsy, ideally using a 16-gauge or larger caliber needle, is the next best choice.

The baseline tests appropriate for most cases of newly diagnosed aggressive B-cell NHL are listed in Table 1. Both hepatitis B and C have been associated with increased risk of NHL. In addition, there is a risk of hepatitis B reactivation following certain NHL therapies. A contrast-enhanced computed tomography (CT) scan in addition to positron emission tomography (PET) is useful to define the extent of disease in situations needing greater definition (eg, lymphadenopathy close to the bowel, cervical and supraclavicular nodal involvement, and lymphadenopathy causing thrombosis or compression of nearby structures).¹⁴ In cases where it is apparent that the patient has advanced stage disease (Ann Arbor stage III/IV) based on imaging, bone marrow biopsy is unlikely to alter the treatment plan. For such patients, if the complete blood count is unremarkable, deferral of bone marrow biopsy may be reasonable. For new cases of DLBCL, assessment for MYC translocation by fluorescence in situ hybridization (FISH) is recommended. If a MYC translocation is identified, then testing for BCL2 and BCL6 translocations by FISH should be performed.

Prior to the initiation of treatment, patients should always undergo a thorough cardiac and pulmonary evaluation, especially if the patient will be treated with an anthracycline or mediastinal irradiation. Central nervous system (CNS) evaluation with magnetic resonance imaging (MRI) and lumbar puncture is essential if there are neurological signs or symptoms. In addition, certain anatomical sites including the testicles, paranasal sinuses, kidney, adrenal glands, and epidural space have been associated with increased involvement of the CNS and may warrant MRI evaluation and lumbar puncture. Certain NHL subtypes like Burkitt lymphoma, high-grade NHL with translocations of MYC and BCL-2 or BCL-6 (double-hit lymphoma), blastoid mantle cell lymphoma, and lymphoblastic lymphoma have a high risk of CNS involvement, and patients with these subtypes need CNS evaluation.

The Lugano classification is used to stage patients with NHL.¹⁴ This classification is based on the Ann Arbor staging system and uses the distribution and number of tumor sites to stage disease. In general, this staging system in isolation is of limited value in predicting survival after treatment. However, the Ann Arbor stage does have prognostic impact when incorporated into risk scoring systems such as the International Prognostic Index (IPI). In clinical practice, the Ann Arbor stage is useful primarily to determine eligibility for localized therapy approaches. The absence or presence of systemic symptoms such as fevers, drenching night sweats, or weight loss (> 10% of baseline over 6 months or less) is designated by A or B, respectively.

Diffuse Large B-Cell Lymphoma

DLBCL is the most common lymphoid neoplasm in adults, accounting for about 25% of all NHL cases.² It is increasingly clear that the diagnostic category of DLBCL is quite heterogeneous in terms of morphology, genetics, and biologic behavior. A number of clinicopathologic subtypes of DLBCL exist, such as T cell/histiocyte–rich large B-cell lymphoma, primary mediastinal large B-cell lymphoma, intravascular large B-cell lymphoma, DLBCL associated with chronic inflammation, lymphomatoid granulomatosis, and EBV-positive large B-cell lymphoma, among others. Gene expression profiling (GEP) can distinguish 2 cell of origin DLBCL subtypes: the germinal center B-cell (GCB) and activated B-cell (ABC) subtypes.¹⁵

DLBCL may be primary (de novo) or may arise through the transformation of many different types of low-grade B-cell lymphomas. This latter scenario is referred to as histologic transformation or transformed lymphoma. In some cases, patients may have a previously diagnosed low-grade B-cell NHL; in other cases, both low-grade and aggressive B-cell NHL may be diagnosed concurrently. The presence of elements of both low-grade and aggressive B-cell NHL in the same biopsy specimen is sometimes referred to as a composite lymphoma.

In the United States, incidence varies by ethnicity, with DLBCL being more common in Caucasians than other races.¹⁶ There is a slight male predominance (55%), median age at diagnosis is 65 years,^16,17 and the incidence increases with age.

Presentation, Pathology, and Prognostic Factors

The most common presentation of patients with DLBCL is rapidly enlarging lymphadenopathy, usually in the neck or abdomen. Extranodal/extramedullary presentation is seen in approximately 40% of cases, with the gastrointestinal (GI) tract being the most common site. However, extranodal DLBCL can arise in virtually any tissue.¹⁸ Nodal DLBCL presents with symptoms related to the sites of involvement (eg, shortness of breath or chest pain with mediastinal lymphadenopathy), while extranodal DLBCL typically presents with symptoms secondary to dysfunction at the site of origin. Up to one third of patients present with constitutional symptoms (B symptoms) and more than 50% have elevated serum lactate dehydrogenase (LDH) at diagnosis.¹⁹

Approximately 40% of patients present with stage I/II disease. Of these, only a subset present with stage I, or truly localized disease (defined as that which can be contained within 1 irradiation field). About 60% of patients present with advanced (stage III–IV) disease.²⁰ The bone marrow is involved in about 15% to 30% of cases. DLBCL involvement of the bone marrow is associated with a less favorable prognosis. Patients with DLBCL elsewhere may have low-grade NHL involvement of the bone marrow. Referred to as discordant bone marrow involvement,²¹ this feature does not carry the same poor prognosis associated with transformed disease²² or DLBCL involvement of the bone marrow.²³

DLBCL is defined as a neoplasm of large B-lymphoid cells with a diffuse growth pattern. The proliferative fraction of cells, as determined by Ki-67 staining, is usually greater than 40%, and may even exceed 90%. Lymph nodes usually demonstrate complete effacement of the normal architecture by sheets of atypical lymphoid cells. Tumor cells in DLBCL generally express pan B-cell antigens (CD19, CD20, CD22, CD79a, Pax-5) as well as CD45 and surface immunoglobulin. Between 20% and 37% of DLBCL cases express the BCL-2 protein,²⁴ and about 70% express the BCL-6 protein.²⁵ C-MYC protein expression is seen in a higher percentage (~ 30%–50%) of cases of DLBCL.²⁶

Many factors are associated with outcome in DLBCL. The IPI score was developed in the pre-rituximab era and is a robust prognostic tool. This simple tool uses 5 easily obtained clinical factors (age > 60 years, impaired performance status, elevated LDH, > 1 extranodal site of disease, and stage III/IV disease). By summing these factors, 4 groups with distinct 5-year overall survival (OS) rates ranging from 26% to 73% were identified (Table 2). Subsequently, modifications were made to adjust for age and stage, with the latest iteration being the NCCN (National Comprehensive Cancer Network) IPI.²⁷ This tool uses age, performance status, LDH ratio (relative to the upper limit of normal), a more precise definition for presence of extranodal sites of disease (defined as lymphomatous involvement in the bone marrow, CNS, liver/GI tract, or lung), and Ann Arbor stage to stratify patients into 4 risk groups with significantly different 5-year OS, ranging from 38% to 96% based on the subgroup. Importantly, the NCCN-IPI was derived in a cohort of patients treated with rituximab-based therapy.

Cytogenetic and molecular factors also predict outcome in DLBCL. The ABC subtype distinguished by GEP has consistently been shown to have inferior outcomes with first-line therapy. As GEP is not routinely available in clinical practice, immunohistochemical (IHC) approaches (eg, the Hans algorithm) have been developed that can approximate the GEP subtypes. These IHC approaches have approximately 80% concordance with GEP.²⁸ The 3 most common chromosomal translocations in DLBCL involve BCL-2, BCL-6 and MYC. MYC-rearranged DLBCLs have a less favorable prognosis.^29,30 Cases in which a MYC translocation occurs in combination with a BCL-2 or BCL-6 translocation are commonly referred to as double-hit lymphoma (DHL); cases with all 3 translocations are referred to as triple-hit lymphoma (THL). Both DHL and THL have a worse prognosis with standard DLBCL therapy compared to non-DHL/THL cases. In the 2016 revised WHO classification, DHL and THL are an entity technically distinct from DLBCL, referred to as high-grade B-cell lymphoma.¹ In some cases, MYC and BCL-2 protein overexpression occurs in the absence of chromosomal translocations. Cases in which MYC and BCL-2 are overexpressed (by IHC) are referred to as double expressor lymphoma (DEL), and also have inferior outcome compared with non-DEL DLBCL.^31,32 Interestingly, MYC protein expression alone does not confer inferior outcomes, unlike isolated MYC translocation, which is associated with inferior outcomes.

Treatment

First-Line Therapy

DLBCL is an aggressive disease and, in most cases, survival without treatment can be measured in weeks to months. The advent of combination chemotherapy (CHOP [cyclophosphamide, doxorubicin, vincristine, and prednisone] or CHOP-like regimens) led to disease-free survival (DFS) rates of 35% to 40% at 3 to 5 years.³³ The addition of rituximab to CHOP (R-CHOP) has improved both progression-free surivial (PFS) and OS.^34,35

Treatment options vary for patients with localized (stage I/II) and advanced (stage III/IV) disease. Options for limited-stage DLBCL include an abbreviated course of R-CHOP (3 or 4 cycles) with involved-field radiation therapy (IFRT) versus a full course (6–8 cycles) of R-CHOP without radiation therapy (RT). Most studies comparing combined modality therapy (chemotherapy plus RT) versus chemotherapy alone were conducted in the pre-rituximab era. With the introduction of rituximab, Persky and colleagues³⁶ studied the use of 3 cycles of R-CHOP followed by RT, demonstrating a slightly improved OS of 92% at 4 years as compared to 88% in a historical cohort. The French LYSA/GOELAMS group performed the only direct comparison in the rituximab era (4 cycles of R-CHOP followed by RT versus 4 cycles of R-CHOP followed by 2 additional cycles of R-CHOP) and reported similar outcomes between both arms,³⁷ with OS of 92% in the R-CHOP alone arm and 96% in the R-CHOP + RT arm (nonsignificant difference statistically). IFRT alone is not recommended other than for palliation in patients who cannot tolerate chemotherapy or combined modality therapy. Stage I and II patients with bulky disease (> 10 cm) have a prognosis similar to patients with advanced DLBCL and should be treated aggressively with 6 to 8 cycles of R-CHOP with or without RT.³⁶

For patients with advanced stage disease, a full course of R-CHOP-21 (6–8 cycles given on a 21-day cycle) is the standard of care. This approach results in OS rates of 70% and 60% at 2 and 5 years, respectively. For older adults unable to tolerate full-dose R-CHOP, attenuated versions of R-CHOP with decreased dose density or decreased dose intensity have been developed.³⁸ Numerous randomized trials have attempted to improve upon the results of R-CHOP-21 using strategies such as infusional chemotherapy (DA-EPOCH-R [etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, rituximab]);³⁹ dose-dense therapy (R-CHOP-14);replacement of rituximab with obinutuzuimab;⁴⁰ addition of novel agents such as bortezomib,⁴¹ lenalidomide,⁴² or ibrutinib^43,44 to R-CHOP; and various maintenance strategies such as rituximab, lenalidomide,⁴⁵ enzastaurin,⁴⁶ and everolimus.⁴⁷ Unfortunately, none of these strategies has been shown to improve OS in DLBCL. In part this appears to be due to the fact that inclusion/exclusion criteria for DLBCL trials have been too strict, such that the most severely ill DLBCL patients are typically not included. As a result, the results in the control arms have ended up better than what was expected based on historical data. Efforts are underway to include all patients in future first-line DLBCL studies.

Currently, autologous hematopoietic cell transplantation (auto-HCT) is not routinely used in the initial treatment of DLBCL. In the pre-rituximab era, numerous trials were conducted in DLBCL patients with high and/or high-intermediate risk disease based on the IPI score to determine if outcomes could be improved with high-dose therapy and auto-HCT as consolidation after patients achieved complete remission with first-line therapy. The results of these trials were conflicting. A 2003 meta-analysis of 11 such trials concluded that the results were very heterogeneous and showed no OS benefit.⁴⁸ More recently, the Southwestern Oncology Group published the results of a prospective trial testing the impact of auto-HCT for consolidation of aggressive NHL patients with an IPI score of 3 to 5 who achieved complete remission with first-line therapy with CHOP or R-CHOP. In this study, 75% of the patients had DLBCL and, of the B-cell NHL patients, 47% received R-CHOP. A survival benefit was seen only in the subgroup that had an IPI score of 4 or 5; a subgroup analysis restricted to those receiving R-CHOP as induction was not performed, however.⁴⁹ As a result, this area remains controversial, with most institutions not routinely performing auto-HCT for any DLBCL patients in first complete remission and some institutions considering auto-HCT in first complete remission for patients with an IPI score of 4 or 5. These studies all used the IPI score to identify high-risk patients. It is possible that the use of newer biomarkers or minimal-residual disease analysis will lead to a more robust algorithm for identifying high-risk patients and selecting patients who might benefit from consolidation of first complete remission with auto-HCT.

For patients with DHL or THL, long-term PFS with standard R-CHOP therapy is poor (20% to 40%).^50,51 Treatment with more intensive first-line regimens such as DA-EPOCH-R, R-hyperCVAD (rituximab plus hyperfractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone), or CODOX-M/IVAC±R (cyclophosphamide, vincristine, doxorubicin, high‐dose methotrexate/ifosfamide, etoposide, high‐dose cytarabine ± rituximab), along with CNS prophylaxis, however, has been shown to produce superior outcomes,⁵² with 3-year relapse-free survival rates of 88% compared to 56% for R-CHOP. For patients who achieve a complete response by PET/CT scan after intensive induction, consolidation with auto-HCT has not been shown to improve outcomes based on retrospective analysis. However for DHL/THL patients who achieve complete response after R-CHOP, PFS was improved if auto-HCT was given as consolidation of first remission.⁵³

Patients with DLBCL have an approximately 5% risk of subsequently developing CNS involvement. Historically (in the pre-rituximab era), patients who presented with multiple sites of extranodal disease and/or extensive bone marrow involvement and/or an elevated LDH had an increased risk (up to 20%–30%) of developing CNS involvement. In addition, patients with involvement of certain anatomical sites (testicular, paranasal sinuses, epidural space) had an increased risk of CNS disease. Several algorithms have been proposed to identify patients who should receive prophylactic CNS therapy. One of the most robust tools for this purpose is the CNS-IPI, which is a 6-point score consisting of the 5 IPI elements, plus 1 additional point if the adrenal glands or kidneys are involved. Importantly, the CNS-IPI was developed and validated in patients treated with R-CHOP-like therapy. Subsequent risk of CNS relapse was 0.6%, 3.4%, and 10.2% for those with low-, intermediate- and high-risk CNS-IPI scores, respectively.⁵⁴ A reasonable strategy, therefore, is to perform CNS prophylaxis in those with a CNS-IPI score of 4 to 6. When CNS prophylaxis is used, intrathecal methotrexate or high-dose systemic methotrexate is most frequently given, with high-dose systemic methotrexate favored over intrathecal chemotherapy given that high-dose methotrexate penetrates the brain and spinal cord parenchyma, in addition to treating the cerebrospinal fluid (CSF).⁵⁵ In contrast, intrathecal therapy only treats the CSF and requires repeated lumbar punctures or placement of an Ommaya reservoir. For DLBCL patients who present with active CSF involvement (known as lymphomatous meningitis), intrathecal chemotherapy treatments are typically given 2 or 3 times weekly until the CSF clears, followed by weekly intrathecal treatment for 4 weeks, and then monthly intrathecal treatment for 4 months.⁵⁶ For those with concurrent systemic and brain parenchymal DLBCL, a strategy of alternating R-CHOP with mid-cycle high-dose methotrexate can be successful. In addition, consolidation with high-dose therapy and auto-HCT improved survival in such patients in 1 retrospective series.⁵⁷

Relapsed/Refractory Disease

Between 30% and 40% of patients with advanced stage DLBCL will either fail to attain a remission with primary therapy (referred to as primary induction failure) or will relapse. In general, for those with progressive or relapsed disease, an updated tissue biopsy is recommended. This is especially true for patients who have had prior complete remission and have new lymph node enlargement, or those who have emergence of new sites of disease at the completion of first-line therapy.

Patients with relapsed disease are treated with systemic second-line platinum-based chemoimmunotherapy, with the usual goal of ultimately proceeding to auto-HCT. A number of platinum-based regimens have been used in this setting such as R-ICE, R-DHAP, R-GDP, R-Gem-Ox, and R-ESHAP. None of these regimens has been shown to be superior in terms of efficacy, and the choice of regimen is typically made based on the anticipated tolerance of the patient in light of comorbidities, laboratory studies, and physician preference. In the CORAL study, R-DHAP (rituximab, dexamethasone, high-dose cytarabine, cisplatin) seemed to show superior PFS in patients with the GCB subtype.⁵⁸ However, this was an unplanned subgroup analysis and R-DHAP was associated with higher renal toxicity.

Several studies have demonstrated that long-term PFS can be observed for relapsed/refractory DLBCL patients who respond to second-line therapy and then undergo high-dose therapy with auto-HCT. The Parma trial remains the only published prospective randomized trial performed in relapsed DLBCL comparing a transplant strategy to a non-transplant strategy. This study, performed in the pre-rituximab era, clearly showed a benefit in terms of DFS and OS in favor of auto-HCT versus salvage therapy alone.⁵⁹ The benefit of auto-HCT in patients treated in the rituximab era, even in patients who experience early failure (within 1 year of diagnosis), was confirmed in a retrospective analysis by the Center for International Blood and Marrow Transplant Research. In this study, a 44% 3-year PFS was seen in the early failure cohort versus 52% in the late failure cohort.⁶⁰

Some DLBCL patients are very unlikely to benefit from auto-HCT. The REFINE study focused on patients with primary induction failure or early relapse within 6 months of completing first-line therapy. Among such patients, primary progressive disease (defined as progression while still receiving first-line therapy), a high NCCN-IPI score at relapse, and MYC rearrangement were risk factors for poor PFS following auto-HCT.⁶¹ Patients with 2 or 3 high-risk features had a 2-year OS of 10.7% compared to 74.3% for those without any high-risk features.

Allogeneic HCT (allo-HCT) is a treatment option for relapsed/refractory DLBCL. This option is more commonly considered for patients in whom an autotransplant has failed to achieve durable remission. For properly selected patients in this setting, a long-term PFS in the 30% to 40% range can be attained.⁶² However, in practice, only about 20% of patients who fail auto-HCT end up undergoing allo-HCT due to rapid progression of disease, age, poor performance status, or lack of suitable donor. It has been proposed that in the coming years, allo-HCT will be utilized less commonly in this setting due to the advent of chimeric antigen receptor T-cell (CAR T) therapy.

CAR T-cell therapy genetically modifies the patient’s own T lymphocytes with a gene that encodes an antigen receptor to direct the T cells against lymphoma cells. Typically, the T cells are genetically modified and expanded in a production facility and then infused back into the patient. Axicabtagene ciloleucel is directed against the CD-19 receptor and has been approved by the US Food and Drug Administration (FDA) for treatment of patients with DLBCL who have failed 2 or more lines of systemic therapy. Use of CAR-T therapy in such patients was examined in a multicenter trial (ZUMA-1), which reported a 54% complete response rate and 52% OS rate at 18 months.⁶³ CAR-T therapy is associated with serious side effects such as cytokine release syndrome, neurological toxicities, and prolonged cytopenias. While there are now some patients with ongoing remission 2 or more years after undergoing CAR-T therapy, it remains uncertain what proportion of patients have been truly cured with this modality. Nevertheless, this new treatment option remains a source of optimism for relapsed and refractory DLBCL patients.

Primary Mediastinal Large B-Cell Lymphoma

Primary mediastinal large B-cell lymphoma (PMBCL) is a form of DLBCL arising in the mediastinum from the thymic B cell. It is an uncommon entity and has clinical and pathologic features distinct from systemic DLBCL.⁶⁴ PMBCL accounts for 2% of all NHLs and about 7% of all DLBCL.²⁰ It typically affects women in the third to fourth decade of life.

Presentation and Prognostic Features

PMBCL usually presents as a locally invasive anterior mediastinal mass, often with a superior vena cava syndrome which may or may not be clinically obvious.⁶⁴ Other presentations include pericardial tamponade, thrombosis of neck veins, and acute airway obstruction. About 80% of patients present with bulky (> 10 cm) stage I or II disease,⁶⁵ with distant spread uncommon on presentation. Morphologically and on GEP, PMBL has a profile more similar to classical Hodgkin lymphoma (cHL) than non-mediastinal DLBCL.⁶⁶ PMBL is distinguished from cHL by immunophenotyping: unlike cHL, PMBCL has pan B cell markers, rarely expresses CD15, and has weak CD30.

Poor prognostic features in PMBCL are Eastern Cooperative Oncology Group (ECOG) performance status greater than 2, pericardial effusion, bulky disease, and elevated serum LDH. The diagnosis of PMBCL can be difficult because the tumor is often encased with extensive fibrosis and necrosis. As a result, a needle biopsy may not yield sufficient tissue, thus making a surgical biopsy often the only viable way to obtain sufficient tissue.

Treatment

Early series suggested that PMBCL is unusually aggressive, with a poor prognosis.⁶⁷ This led to studies using more aggressive chemotherapy regimens (often in combination with mediastinal radiation) as well as upfront auto-HCT.^68–70 The addition of rituximab to treatment regimens significantly improved outcomes in PMBCL. For example, a subgroup analysis of the PMBCL patients in the MinT trial revealed a 3-year event-free survival (EFS) of 78%⁷¹ when rituximab was combined with CHOP. Because of previous reports demonstrating radiosensitivity of PMBL, radiation was traditionally sequenced into treatment regimens for PMBL. However, this is associated with higher long-term toxicities, often a concern in PMBCL patients given that the disease frequently affects younger females, and given that breast tissue will be in the radiation field. For patients with a strong personal or family history of breast cancer or cardiovascular disease, these concerns are even more significant. More recently, the DA-EPOCH-R regimen has been shown to produce very high rates (80%–90%) of long-term DFS, without the need for mediastinal radiation in most cases.^72,73 For patients receiving R-CHOP, consolidation with mediastinal radiation is still commonly given. This approach also leads to high rates of long-term remission and, although utilizing mediastinal radiation, allows for less intensive chemotherapy. Determining which approach is most appropriate for an individual patient requires an assessment of the risks of each treatment option for that patient. A randomized trial by the International Extranodal Lymphoma Study Group (IELSG37) is evaluating whether RT may be safely omitted in PMBCL patients who achieve a complete metabolic response after R-CHOP.

Most relapses of PMBCL occur within the first 1 to 2 years and often present with extranodal disease in various organs. For those with relapsed or refractory disease, high-dose chemotherapy followed by auto-HCT provides 5-year survival rates of 50% to 80%.^74–76 In a phase 1b trial evaluating the role of pembrolizumab in relapsed/refractory patients (KEYNOTE-13), 7 of 17 PMBCL patients achieved responses, with an additional 6 demonstrating stable disease.⁷⁷ This provides an additional option for patients who might be too weak to undergo auto-HCT or for those who relapse following auto-HCT.

Mantle Cell Lymphoma

The name mantle cell lymphoma (MCL) is based on the presumed normal cell counterpart to MCL, which is believed to be found in the mantle zone surrounding germinal center follicles. It represents approximately 6% of all NHL cases in the United States and Europe.⁷⁸ MCL occurs at a median age of 63 to 68 years and has a male predominance.

Presentation and Prognostic Features

Patients can present with a broad spectrum of clinical features, and most patients (70%) present with advanced disease.⁷⁹ Up to one third of patients have B symptoms, with most demonstrating lymphadenopathy and bone marrow involvement. Approximately 25% present with extranodal disease as the primary presentation (eg, GI tract, pleura, breast, or orbits). MCL can involve any part of the GI tract and often presents as polypoid lesions.

Histologically, the pattern of MCL may be diffuse, nodular, mantle zone, or a combination of the these; morphologically, MCL can range from small, more irregular lymphocytes to lymphoblast-like cells. Blastoid and pleomorphic variants of MCL have a higher proliferation index and a more aggressive clinical course than other variants. MCL is characterized by the expression of pan B cell antigens (CD19+, CD20+) with coexpression of the T-cell antigen CD5, lack of CD23 expression, and nuclear expression of cyclin D1. Nuclear staining for cyclin D1 is present in more than 98% of cases.⁸⁰ In rare cases, CD5 or cyclin D1 may be negative.⁸⁰ Most MCL cases have a unique translocation that fuses the immunoglobulin heavy chain gene promoter (14q32) to the promoter of the BCL-1 gene (11q13), which encodes the cyclin D1 protein. This translocation is not unique to MCL and can be present in multiple myeloma as well. Interestingly, cyclin D1 is overproduced in cases lacking t(11:14), likely from other point mutations resulting in its overexpression.⁸¹ Cyclin D1–negative tumors overexpress cyclin D2 or D3, with no apparent difference in clinical behavior or outcome.⁸² In cyclin D1–negative cases, SOX11 expression may help with diagnosis.⁸³ A proliferation rate greater than 30% (as measured by Ki-67 staining), low SOX11 expression, and presence of p53 mutations have all been associated with adverse outcome.

In a minority of cases, MCL follows an indolent clinical course. For the remainder, however, MCL is an aggressive disease that generally requires treatment soon after diagnosis. When initially described in the 1980s and 1990s, treatment of MCL was characterized by low complete response rates, short durations of remission, repeated recurrences, and a median survival in the 2- to 5-year range.⁸⁴ In recent years, intensive regimens incorporating rituximab and high-dose cytarabine with or without auto-HCT have been developed and are associated with high complete response rates and median duration of first remission in the 6- to 9-year range.^85–87 Several prognostic indices have been applied to patients with MCL, including the IPI, the Follicular Lymphoma International Prognostic Index , and the Mantle Cell Lymphoma International Prognostic Index (MIPI). The MIPI was originally described based on a cohort from the period 1996 to 2004,⁸⁸ and subsequently confirmed in a separate cohort of 958 patients with MCL treated on prospective trials between 2004 and 2010.⁸⁹ The MIPI score can identify 3 risk groups with significant survival differences (83%, 63%, and 34% survival at 5 years). A refined version of the MIPI score, the combined MIPI or MIPI-c, incorporates proliferation rate and is better able to stratify patients.⁹⁰ The blastoid variant of MCL follows a more aggressive clinical course and is associated with a high proliferation rate, shorter remissions, and a higher rate of CNS involvement.⁹¹

In most patients, MCL is an aggressive disease with a short OS without treatment. A subset of patients may have a more indolent course,⁹² but unfortunately reliable factors that identify this group at the time of diagnosis are not available. Pretreatment evaluation is as with other lymphomas, with lumbar puncture and MRI of the brain also recommended for patients with the blastoid variant. For those presenting with GI symptoms, endoscopy is recommended as part of the initial evaluation as well.

Treatment

First-line Therapy

For patients under age 65 to 70 years with a good performance status and few comorbidities, an intensive induction regimen (such as R-CHOP/R-DHAP, Maxi-R-CHOP/R-araC, or R-DHAP) followed by consolidation with auto-HCT is commonly given, with a goal of achieving a durable (6–9 year) first remission.^87,93,94 Auto-HCT is now routinely followed by 3 years of maintenance rituximab based on the survival benefit seen in the recent LYSA trial.⁹³ At many centers, auto-HCT in first remission is a standard of care, with the greatest benefit seen in patients who have achieved a complete remission with no more than 2 lines of chemotherapy.⁹⁵ However, there remains some controversy about whether all patients truly benefit from auto-HCT in first remission, and current research efforts are focused on identifying patients most likely to benefit from auto-HCT and incorporation of new agents into first-line regimens. For patients who are not candidates for auto-HCT, bendamustine plus rituximab (BR) or R-CHOP alone or followed by maintenance rituximab is a reasonable approach.⁹⁶ Based on the StiL and BRIGHT trials, BR seems to have less toxicity and higher rates of response with no difference in OS when compared to R-CHOP.^97,98

In summary, dose-intense induction chemotherapy with consolidative auto-HCT results in high rates of long-term remission and can be considered in MCL patients who lack significant comorbidities and who understand the risks and benefits of this approach. For other patients, the less aggressive frontline approaches are more appropriate.

Relapsed/Refractory Disease

Despite initial high response rates, most patients with MCL will eventually relapse. For example, most patients given CHOP or R-CHOP alone as first-line therapy will relapse within 2 years.⁹⁹ In recent years, a number of therapies have emerged for relapsed/refractory MCL; however, the optimal sequencing of these is unclear. FDA-approved options for relapsed/refractory MCL include the proteasome inhibitor bortezomib,^100,101 the BTK inhibitors ibrutinib^102,103 and acalabrutinib,¹⁰⁴ and the immunomodulatory agent lenalidomide.¹⁰⁵

Auto-HCT can be considered for patients who did not undergo auto-HCT as part of first-line therapy and who had a reasonably long first remission.⁹⁵ Allo-HCT has curative potential in MCL with good evidence of a graft-versus-lymphoma effect. With a matched related or matched unrelated donor, the chance for treatment-related mortality is 15% to 25% at 1 to 2 years, with a 50% to 60% chance for long-term PFS. However, given the risk of treatment-related mortality and graft-versus-host disease, this option is typically reserved for patients with early relapse after auto-HCT, multiple relapses, or relatively chemotherapy-unresponsive disease.^95,106 A number of clinical trials for relapsed/refractory MCL are ongoing, and participation in these is encouraged whenever possible.

Burkitt Lymphoma

Burkitt lymphoma is a rare, aggressive and highly curable subtype of NHL. It can occur at any age, although peak incidence is in the first decade of life. There are 3 distinct clinical forms of Burkitt lymphoma.¹⁰⁷ The endemic form is common in African children and commonly involves the jaw and kidneys. The sporadic (nonendemic) form accounts for 1% to 2% of all lymphomas in the United States and Western Europe and usually has an abdominal presentation. The immunodeficiency-associated form is commonly seen in HIV patients with a relatively preserved CD4 cell count.

Patients typically present with rapidly growing masses and tumor lysis syndrome. CNS and bone marrow involvement are common. Burkitt lymphoma cells are high-grade, rapidly proliferating medium-sized cells with a monomorphic appearance. Biopsies show a classic histological appearance known as a “starry sky pattern” due to benign macrophages engulfing debris resulting from apoptosis. It is derived from a germinal center B cell and has distinct oncogenic pathways. Translocations such as t(8;14), t(2;8) or t(8;22) juxtapose the MYC locus with immunoglobulin heavy or light chain loci and result in MYC overexpression. Burkitt lymphoma is typically CD10-positive and BCL-2-negative, with a MYC translocation and a proliferation rate greater than 95%.

With conventional NHL regimens, Burkitt lymphoma had a poor prognosis, with complete remission in the 30% to 70% range and low rates of long-term remission. With the introduction of short-term, dose-intensive, multiagent chemotherapy regimens (adapted from pediatric acute lymphoblastic leukemia [ALL] regimens), the complete remission rate improved to 60% to 90%.¹⁰⁷ Early stage disease (localized or completely resected intra-abdominal disease) can have complete remission rates of 100%, with 2- to 5-year freedom-from-progression rates of 95%. CNS prophylaxis, including high-dose methotrexate, high-dose cytarabine, and intrathecal chemotherapy, is a standard component of Burkitt lymphoma regimens (CNS relapse rates can reach 50% without prophylactic therapy). Crucially, relapse after 1 to 2 years is very rare following complete response to induction therapy. Classically, several intensive regimens have been used for Burkitt lymphoma. In recent years, the most commonly used regimens have been the modified Magrath regimen of R-CODOX-M/IVAC and R-hyperCVAD. DA-EPOCH-R has also been used, typically for older, more frail, or HIV-positive patients. However, at the American Society of Hematology 2017 annual meeting, results from the NCI 9177 trial were presented which validated, in a prospective multi-center fashion, the use of DA-EPOCH-R in all Burkitt lymphoma patients.¹⁰⁸ In NCI 9177, low-risk patients (defined as normal LDH, ECOG performance score 0 or 1, ≤ stage II, and no tumor lesion > 7 cm) received 2 cycles of DA-EPOCH-R without intrathecal therapy followed by PET. If interim PET was negative, low-risk patients then received 1 more cycle of DA-EPOCH-R. High-risk patients with negative brain MRI and CSF cytology/flow cytometry received 2 cycles of DA-EPOCH-R with intrathecal therapy (2 doses per cycle) followed by PET. Unless interim PET showed progression, high-risk patients received 4 additional cycles of DA-EPOCH-R including methotrexate 12 mg intrathecally on days 1 and 5 (8 total doses). With a median follow-up of 36 months, this regimen resulted in an EFS of 85.7%. As expected, patients with CNS, marrow, or peripheral blood involvement fared worse. For those without CNS, marrow, or peripheral blood involvement, the results were excellent, with an EFS of 94.6% compared to 62.8% for those with CNS, bone marrow, or blood involvement at diagnosis.

Although no standard of care has been defined, patients with relapsed/refractory Burkitt lymphoma are often given standard second-line aggressive NHL regimens (eg, R-ICE); for those with chemosensitive disease, auto- or allo-HCT is often pursued, with long-term remissions possible following HCT.¹⁰⁹

Lymphoblastic Lymphoma

Lymphoblastic lymphoma (LBL) is a rare disease postulated to arise from precursor B or T lymphoblasts at varying stages of differentiation. Accounting for approximately 2% of all NHLs, 85% to 90% of all cases have a T-cell phenotype, while B-cell LBL comprises approximately 10% to 15% of cases. LBL and ALL are thought to represent the same disease entity, but LBL has been arbitrarily defined as cases with lymph node or mediastinal disease. Those with significant (> 25%) bone marrow or peripheral blood involvement are classified as ALL.

Precursor T-cell LBL patients are usually adolescent and young males who commonly present with a mediastinal mass and peripheral lymphadenopathy. Precursor B-cell LBL patients are usually older (median age 39 years) with peripheral lymphadenopathy and extranodal involvement. Mediastinal involvement with B-cell LBL is uncommon, and there is no male predominance. LBL has a propensity for dissemination to the bone marrow and CNS.

Morphologically, the tumor cells are medium sized, with a scant cytoplasm and finely dispersed chromatin. Mitotic features and apoptotic bodies are present since it is a high-grade malignancy. The lymphoblasts are typically positive for CD7 and either surface or cytoplasmic CD3. Terminal deoxynucleotidyl transferase expression is a defining feature. Other markers such as CD19, CD22, CD20, CD79a, CD45, and CD10 are variably expressed. Poor prognostic factors in T-cell LBL are female gender, age greater than 35 years, complex cytogenetics, and lack of a matched sibling donor.

Regimens for LBL are based on dose-dense, multi-agent protocols used in ALL. Most of these regimens are characterized by intensive remission-induction chemotherapy, CNS prophylaxis, a phase of consolidation therapy, and a prolonged maintenance phase, often lasting for 12 to 18 months with long-term DFS rates of 40% to 70%.^110,111 High-dose therapy with auto-HCT or allo-HCT in first complete response has been evaluated in an attempt to reduce the incidence of relapse.¹¹² However, the intensity of primary chemotherapy appears to be a stronger determinant of long-term survival than the use of HCT as consolidation. As a result, HCT is not routinely applied to patients in first complete remission following modern induction regimens. After relapse, prognosis is poor, with median survival rates of 6 to 9 months with conventional chemotherapy, although long-term survival rates of 30% and 20%, respectively, are reported after HCT in relapsed and primary refractory disease.¹¹³

Treatment options in relapsed disease are limited. Nelarabine can produce responses in up to 40% of relapsed/refractory LBL/ALL patients.¹¹⁴ For the minority of LBL patients with a B-cell phenotype, emerging options for relapsed/refractory LBL/ALL such as inotuzumab, blinatumomab, or anti-CD19 CAR T-cell therapy should be considered. These are not options for the majority who have a T-cell phenotype, and treatment options for these patients are limited to conventional relapsed/refractory ALL and aggressive NHL regimens.

Summary

Aggressive NHLs are characterized by rapid clinical progression without therapy. However, a significant proportion of patients are cured with appropriate combination chemotherapy or combined modality (chemotherapy + RT) regimens. In contrast, the indolent lymphomas have a relatively good prognosis (median survival of 10 years or longer) but usually are not curable in advanced clinical stages. Overall 5-year survival for aggressive NHLs with current treatment is approximately 50% to 60%, with relapses typically occurring within the first 5 years. Treatment strategies for relapsed patients offer some potential for cure; however, clinical trial participation should be encouraged whenever possible to investigate new approaches for improving outcomes in this patient population.

Introduction

Non-Hodgkin lymphoma (NHL) comprises a wide variety of malignant hematologic disorders with varying clinical and biological features. The more than 60 separate NHL subtypes can be classified according to cell of origin (B cell versus T cell), anatomical location (eg, orbital, testicular, bone, central nervous system), clinical behavior (indolent versus aggressive), histological features, or cytogenetic abnormalities. Although various NHL classification schemes have been used over the years, the World Health Organization (WHO) classification is now widely accepted as the definitive pathologic classification system for lymphoproliferative disorders, incorporating morphologic, immunohistochemical, flow cytometric, cytogenetic, and molecular features.¹ While the pathologic and molecular subclassification of NHL has become increasingly refined in recent years, from a management standpoint, classification based on clinical behavior remains very useful. This approach separates NHL subtypes into indolent versus aggressive categories. Whereas indolent NHLs may remain clinically insignificant for months to years, aggressive B-cell NHLs generally become life-threatening within weeks to months without treatment.

Epidemiology

Data from cancer registries show a steady, unexplainable increase in the incidence of NHL during the second half of the 20th century; the incidence has subsequently plateaued. There was a significant increase in NHL incidence between 1970 and 1995, which has been attributed in part to the HIV epidemic. More than 72,000 new cases of NHL were diagnosed in the United States in 2017, compared to just over 8000 cases of Hodgkin lymphoma, making NHL the sixth most common cancer in adult men and the fifth most common in adult women.² NHL appears to occur more frequently in Western countries than in Asian populations.

Various factors associated with increased risk for B-cell NHL have been identified over the years, including occupational and environmental exposure to certain pesticides and herbicides,³ immunosuppression associated with HIV infection,⁴ autoimmune disorders,⁵ iatrogenically induced immune suppression in the post-transplant and other settings,⁶ family history of NHL,⁷ and a personal history of a prior cancer, including Hodgkin lymphoma and prior NHL.⁸ In terms of infectious agents associated with aggressive B-cell NHLs, Epstein-Barr virus (EBV) has a clear pathogenic role in Burkitt lymphoma, in many cases of post-transplant lymphoproliferative disorders, and in some cases of HIV-related aggressive B-cell lymphoma.⁹ Human herpesvirus-8 viral genomes have been found in virtually all cases of primary effusion lymphomas.¹⁰ Epidemiological studies also have linked hepatitis B and C to increased incidences of certain NHL subtypes,^11–13 including primary hepatic diffuse large B-cell lymphoma (DLBCL). Similarly, Helicobacter pylori has been associated with gastric DLBCL.

Staging and Work-Up

A tissue biopsy is essential in the diagnosis and management of NHL. The most significant disadvantage of fine-needle aspiration cytology is the lack of histologic architecture. The optimal specimen is an excisional biopsy; when this cannot be performed, a core needle biopsy, ideally using a 16-gauge or larger caliber needle, is the next best choice.

The baseline tests appropriate for most cases of newly diagnosed aggressive B-cell NHL are listed in Table 1. Both hepatitis B and C have been associated with increased risk of NHL. In addition, there is a risk of hepatitis B reactivation following certain NHL therapies. A contrast-enhanced computed tomography (CT) scan in addition to positron emission tomography (PET) is useful to define the extent of disease in situations needing greater definition (eg, lymphadenopathy close to the bowel, cervical and supraclavicular nodal involvement, and lymphadenopathy causing thrombosis or compression of nearby structures).¹⁴ In cases where it is apparent that the patient has advanced stage disease (Ann Arbor stage III/IV) based on imaging, bone marrow biopsy is unlikely to alter the treatment plan. For such patients, if the complete blood count is unremarkable, deferral of bone marrow biopsy may be reasonable. For new cases of DLBCL, assessment for MYC translocation by fluorescence in situ hybridization (FISH) is recommended. If a MYC translocation is identified, then testing for BCL2 and BCL6 translocations by FISH should be performed.

Prior to the initiation of treatment, patients should always undergo a thorough cardiac and pulmonary evaluation, especially if the patient will be treated with an anthracycline or mediastinal irradiation. Central nervous system (CNS) evaluation with magnetic resonance imaging (MRI) and lumbar puncture is essential if there are neurological signs or symptoms. In addition, certain anatomical sites including the testicles, paranasal sinuses, kidney, adrenal glands, and epidural space have been associated with increased involvement of the CNS and may warrant MRI evaluation and lumbar puncture. Certain NHL subtypes like Burkitt lymphoma, high-grade NHL with translocations of MYC and BCL-2 or BCL-6 (double-hit lymphoma), blastoid mantle cell lymphoma, and lymphoblastic lymphoma have a high risk of CNS involvement, and patients with these subtypes need CNS evaluation.

The Lugano classification is used to stage patients with NHL.¹⁴ This classification is based on the Ann Arbor staging system and uses the distribution and number of tumor sites to stage disease. In general, this staging system in isolation is of limited value in predicting survival after treatment. However, the Ann Arbor stage does have prognostic impact when incorporated into risk scoring systems such as the International Prognostic Index (IPI). In clinical practice, the Ann Arbor stage is useful primarily to determine eligibility for localized therapy approaches. The absence or presence of systemic symptoms such as fevers, drenching night sweats, or weight loss (> 10% of baseline over 6 months or less) is designated by A or B, respectively.

Diffuse Large B-Cell Lymphoma

DLBCL is the most common lymphoid neoplasm in adults, accounting for about 25% of all NHL cases.² It is increasingly clear that the diagnostic category of DLBCL is quite heterogeneous in terms of morphology, genetics, and biologic behavior. A number of clinicopathologic subtypes of DLBCL exist, such as T cell/histiocyte–rich large B-cell lymphoma, primary mediastinal large B-cell lymphoma, intravascular large B-cell lymphoma, DLBCL associated with chronic inflammation, lymphomatoid granulomatosis, and EBV-positive large B-cell lymphoma, among others. Gene expression profiling (GEP) can distinguish 2 cell of origin DLBCL subtypes: the germinal center B-cell (GCB) and activated B-cell (ABC) subtypes.¹⁵

DLBCL may be primary (de novo) or may arise through the transformation of many different types of low-grade B-cell lymphomas. This latter scenario is referred to as histologic transformation or transformed lymphoma. In some cases, patients may have a previously diagnosed low-grade B-cell NHL; in other cases, both low-grade and aggressive B-cell NHL may be diagnosed concurrently. The presence of elements of both low-grade and aggressive B-cell NHL in the same biopsy specimen is sometimes referred to as a composite lymphoma.

In the United States, incidence varies by ethnicity, with DLBCL being more common in Caucasians than other races.¹⁶ There is a slight male predominance (55%), median age at diagnosis is 65 years,^16,17 and the incidence increases with age.

Presentation, Pathology, and Prognostic Factors

The most common presentation of patients with DLBCL is rapidly enlarging lymphadenopathy, usually in the neck or abdomen. Extranodal/extramedullary presentation is seen in approximately 40% of cases, with the gastrointestinal (GI) tract being the most common site. However, extranodal DLBCL can arise in virtually any tissue.¹⁸ Nodal DLBCL presents with symptoms related to the sites of involvement (eg, shortness of breath or chest pain with mediastinal lymphadenopathy), while extranodal DLBCL typically presents with symptoms secondary to dysfunction at the site of origin. Up to one third of patients present with constitutional symptoms (B symptoms) and more than 50% have elevated serum lactate dehydrogenase (LDH) at diagnosis.¹⁹

Approximately 40% of patients present with stage I/II disease. Of these, only a subset present with stage I, or truly localized disease (defined as that which can be contained within 1 irradiation field). About 60% of patients present with advanced (stage III–IV) disease.²⁰ The bone marrow is involved in about 15% to 30% of cases. DLBCL involvement of the bone marrow is associated with a less favorable prognosis. Patients with DLBCL elsewhere may have low-grade NHL involvement of the bone marrow. Referred to as discordant bone marrow involvement,²¹ this feature does not carry the same poor prognosis associated with transformed disease²² or DLBCL involvement of the bone marrow.²³

DLBCL is defined as a neoplasm of large B-lymphoid cells with a diffuse growth pattern. The proliferative fraction of cells, as determined by Ki-67 staining, is usually greater than 40%, and may even exceed 90%. Lymph nodes usually demonstrate complete effacement of the normal architecture by sheets of atypical lymphoid cells. Tumor cells in DLBCL generally express pan B-cell antigens (CD19, CD20, CD22, CD79a, Pax-5) as well as CD45 and surface immunoglobulin. Between 20% and 37% of DLBCL cases express the BCL-2 protein,²⁴ and about 70% express the BCL-6 protein.²⁵ C-MYC protein expression is seen in a higher percentage (~ 30%–50%) of cases of DLBCL.²⁶

Many factors are associated with outcome in DLBCL. The IPI score was developed in the pre-rituximab era and is a robust prognostic tool. This simple tool uses 5 easily obtained clinical factors (age > 60 years, impaired performance status, elevated LDH, > 1 extranodal site of disease, and stage III/IV disease). By summing these factors, 4 groups with distinct 5-year overall survival (OS) rates ranging from 26% to 73% were identified (Table 2). Subsequently, modifications were made to adjust for age and stage, with the latest iteration being the NCCN (National Comprehensive Cancer Network) IPI.²⁷ This tool uses age, performance status, LDH ratio (relative to the upper limit of normal), a more precise definition for presence of extranodal sites of disease (defined as lymphomatous involvement in the bone marrow, CNS, liver/GI tract, or lung), and Ann Arbor stage to stratify patients into 4 risk groups with significantly different 5-year OS, ranging from 38% to 96% based on the subgroup. Importantly, the NCCN-IPI was derived in a cohort of patients treated with rituximab-based therapy.

Cytogenetic and molecular factors also predict outcome in DLBCL. The ABC subtype distinguished by GEP has consistently been shown to have inferior outcomes with first-line therapy. As GEP is not routinely available in clinical practice, immunohistochemical (IHC) approaches (eg, the Hans algorithm) have been developed that can approximate the GEP subtypes. These IHC approaches have approximately 80% concordance with GEP.²⁸ The 3 most common chromosomal translocations in DLBCL involve BCL-2, BCL-6 and MYC. MYC-rearranged DLBCLs have a less favorable prognosis.^29,30 Cases in which a MYC translocation occurs in combination with a BCL-2 or BCL-6 translocation are commonly referred to as double-hit lymphoma (DHL); cases with all 3 translocations are referred to as triple-hit lymphoma (THL). Both DHL and THL have a worse prognosis with standard DLBCL therapy compared to non-DHL/THL cases. In the 2016 revised WHO classification, DHL and THL are an entity technically distinct from DLBCL, referred to as high-grade B-cell lymphoma.¹ In some cases, MYC and BCL-2 protein overexpression occurs in the absence of chromosomal translocations. Cases in which MYC and BCL-2 are overexpressed (by IHC) are referred to as double expressor lymphoma (DEL), and also have inferior outcome compared with non-DEL DLBCL.^31,32 Interestingly, MYC protein expression alone does not confer inferior outcomes, unlike isolated MYC translocation, which is associated with inferior outcomes.

Treatment

First-Line Therapy

DLBCL is an aggressive disease and, in most cases, survival without treatment can be measured in weeks to months. The advent of combination chemotherapy (CHOP [cyclophosphamide, doxorubicin, vincristine, and prednisone] or CHOP-like regimens) led to disease-free survival (DFS) rates of 35% to 40% at 3 to 5 years.³³ The addition of rituximab to CHOP (R-CHOP) has improved both progression-free surivial (PFS) and OS.^34,35

Treatment options vary for patients with localized (stage I/II) and advanced (stage III/IV) disease. Options for limited-stage DLBCL include an abbreviated course of R-CHOP (3 or 4 cycles) with involved-field radiation therapy (IFRT) versus a full course (6–8 cycles) of R-CHOP without radiation therapy (RT). Most studies comparing combined modality therapy (chemotherapy plus RT) versus chemotherapy alone were conducted in the pre-rituximab era. With the introduction of rituximab, Persky and colleagues³⁶ studied the use of 3 cycles of R-CHOP followed by RT, demonstrating a slightly improved OS of 92% at 4 years as compared to 88% in a historical cohort. The French LYSA/GOELAMS group performed the only direct comparison in the rituximab era (4 cycles of R-CHOP followed by RT versus 4 cycles of R-CHOP followed by 2 additional cycles of R-CHOP) and reported similar outcomes between both arms,³⁷ with OS of 92% in the R-CHOP alone arm and 96% in the R-CHOP + RT arm (nonsignificant difference statistically). IFRT alone is not recommended other than for palliation in patients who cannot tolerate chemotherapy or combined modality therapy. Stage I and II patients with bulky disease (> 10 cm) have a prognosis similar to patients with advanced DLBCL and should be treated aggressively with 6 to 8 cycles of R-CHOP with or without RT.³⁶

For patients with advanced stage disease, a full course of R-CHOP-21 (6–8 cycles given on a 21-day cycle) is the standard of care. This approach results in OS rates of 70% and 60% at 2 and 5 years, respectively. For older adults unable to tolerate full-dose R-CHOP, attenuated versions of R-CHOP with decreased dose density or decreased dose intensity have been developed.³⁸ Numerous randomized trials have attempted to improve upon the results of R-CHOP-21 using strategies such as infusional chemotherapy (DA-EPOCH-R [etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, rituximab]);³⁹ dose-dense therapy (R-CHOP-14);replacement of rituximab with obinutuzuimab;⁴⁰ addition of novel agents such as bortezomib,⁴¹ lenalidomide,⁴² or ibrutinib^43,44 to R-CHOP; and various maintenance strategies such as rituximab, lenalidomide,⁴⁵ enzastaurin,⁴⁶ and everolimus.⁴⁷ Unfortunately, none of these strategies has been shown to improve OS in DLBCL. In part this appears to be due to the fact that inclusion/exclusion criteria for DLBCL trials have been too strict, such that the most severely ill DLBCL patients are typically not included. As a result, the results in the control arms have ended up better than what was expected based on historical data. Efforts are underway to include all patients in future first-line DLBCL studies.

Currently, autologous hematopoietic cell transplantation (auto-HCT) is not routinely used in the initial treatment of DLBCL. In the pre-rituximab era, numerous trials were conducted in DLBCL patients with high and/or high-intermediate risk disease based on the IPI score to determine if outcomes could be improved with high-dose therapy and auto-HCT as consolidation after patients achieved complete remission with first-line therapy. The results of these trials were conflicting. A 2003 meta-analysis of 11 such trials concluded that the results were very heterogeneous and showed no OS benefit.⁴⁸ More recently, the Southwestern Oncology Group published the results of a prospective trial testing the impact of auto-HCT for consolidation of aggressive NHL patients with an IPI score of 3 to 5 who achieved complete remission with first-line therapy with CHOP or R-CHOP. In this study, 75% of the patients had DLBCL and, of the B-cell NHL patients, 47% received R-CHOP. A survival benefit was seen only in the subgroup that had an IPI score of 4 or 5; a subgroup analysis restricted to those receiving R-CHOP as induction was not performed, however.⁴⁹ As a result, this area remains controversial, with most institutions not routinely performing auto-HCT for any DLBCL patients in first complete remission and some institutions considering auto-HCT in first complete remission for patients with an IPI score of 4 or 5. These studies all used the IPI score to identify high-risk patients. It is possible that the use of newer biomarkers or minimal-residual disease analysis will lead to a more robust algorithm for identifying high-risk patients and selecting patients who might benefit from consolidation of first complete remission with auto-HCT.

For patients with DHL or THL, long-term PFS with standard R-CHOP therapy is poor (20% to 40%).^50,51 Treatment with more intensive first-line regimens such as DA-EPOCH-R, R-hyperCVAD (rituximab plus hyperfractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone), or CODOX-M/IVAC±R (cyclophosphamide, vincristine, doxorubicin, high‐dose methotrexate/ifosfamide, etoposide, high‐dose cytarabine ± rituximab), along with CNS prophylaxis, however, has been shown to produce superior outcomes,⁵² with 3-year relapse-free survival rates of 88% compared to 56% for R-CHOP. For patients who achieve a complete response by PET/CT scan after intensive induction, consolidation with auto-HCT has not been shown to improve outcomes based on retrospective analysis. However for DHL/THL patients who achieve complete response after R-CHOP, PFS was improved if auto-HCT was given as consolidation of first remission.⁵³

Patients with DLBCL have an approximately 5% risk of subsequently developing CNS involvement. Historically (in the pre-rituximab era), patients who presented with multiple sites of extranodal disease and/or extensive bone marrow involvement and/or an elevated LDH had an increased risk (up to 20%–30%) of developing CNS involvement. In addition, patients with involvement of certain anatomical sites (testicular, paranasal sinuses, epidural space) had an increased risk of CNS disease. Several algorithms have been proposed to identify patients who should receive prophylactic CNS therapy. One of the most robust tools for this purpose is the CNS-IPI, which is a 6-point score consisting of the 5 IPI elements, plus 1 additional point if the adrenal glands or kidneys are involved. Importantly, the CNS-IPI was developed and validated in patients treated with R-CHOP-like therapy. Subsequent risk of CNS relapse was 0.6%, 3.4%, and 10.2% for those with low-, intermediate- and high-risk CNS-IPI scores, respectively.⁵⁴ A reasonable strategy, therefore, is to perform CNS prophylaxis in those with a CNS-IPI score of 4 to 6. When CNS prophylaxis is used, intrathecal methotrexate or high-dose systemic methotrexate is most frequently given, with high-dose systemic methotrexate favored over intrathecal chemotherapy given that high-dose methotrexate penetrates the brain and spinal cord parenchyma, in addition to treating the cerebrospinal fluid (CSF).⁵⁵ In contrast, intrathecal therapy only treats the CSF and requires repeated lumbar punctures or placement of an Ommaya reservoir. For DLBCL patients who present with active CSF involvement (known as lymphomatous meningitis), intrathecal chemotherapy treatments are typically given 2 or 3 times weekly until the CSF clears, followed by weekly intrathecal treatment for 4 weeks, and then monthly intrathecal treatment for 4 months.⁵⁶ For those with concurrent systemic and brain parenchymal DLBCL, a strategy of alternating R-CHOP with mid-cycle high-dose methotrexate can be successful. In addition, consolidation with high-dose therapy and auto-HCT improved survival in such patients in 1 retrospective series.⁵⁷

Relapsed/Refractory Disease

Between 30% and 40% of patients with advanced stage DLBCL will either fail to attain a remission with primary therapy (referred to as primary induction failure) or will relapse. In general, for those with progressive or relapsed disease, an updated tissue biopsy is recommended. This is especially true for patients who have had prior complete remission and have new lymph node enlargement, or those who have emergence of new sites of disease at the completion of first-line therapy.

Patients with relapsed disease are treated with systemic second-line platinum-based chemoimmunotherapy, with the usual goal of ultimately proceeding to auto-HCT. A number of platinum-based regimens have been used in this setting such as R-ICE, R-DHAP, R-GDP, R-Gem-Ox, and R-ESHAP. None of these regimens has been shown to be superior in terms of efficacy, and the choice of regimen is typically made based on the anticipated tolerance of the patient in light of comorbidities, laboratory studies, and physician preference. In the CORAL study, R-DHAP (rituximab, dexamethasone, high-dose cytarabine, cisplatin) seemed to show superior PFS in patients with the GCB subtype.⁵⁸ However, this was an unplanned subgroup analysis and R-DHAP was associated with higher renal toxicity.

Several studies have demonstrated that long-term PFS can be observed for relapsed/refractory DLBCL patients who respond to second-line therapy and then undergo high-dose therapy with auto-HCT. The Parma trial remains the only published prospective randomized trial performed in relapsed DLBCL comparing a transplant strategy to a non-transplant strategy. This study, performed in the pre-rituximab era, clearly showed a benefit in terms of DFS and OS in favor of auto-HCT versus salvage therapy alone.⁵⁹ The benefit of auto-HCT in patients treated in the rituximab era, even in patients who experience early failure (within 1 year of diagnosis), was confirmed in a retrospective analysis by the Center for International Blood and Marrow Transplant Research. In this study, a 44% 3-year PFS was seen in the early failure cohort versus 52% in the late failure cohort.⁶⁰

Some DLBCL patients are very unlikely to benefit from auto-HCT. The REFINE study focused on patients with primary induction failure or early relapse within 6 months of completing first-line therapy. Among such patients, primary progressive disease (defined as progression while still receiving first-line therapy), a high NCCN-IPI score at relapse, and MYC rearrangement were risk factors for poor PFS following auto-HCT.⁶¹ Patients with 2 or 3 high-risk features had a 2-year OS of 10.7% compared to 74.3% for those without any high-risk features.

Allogeneic HCT (allo-HCT) is a treatment option for relapsed/refractory DLBCL. This option is more commonly considered for patients in whom an autotransplant has failed to achieve durable remission. For properly selected patients in this setting, a long-term PFS in the 30% to 40% range can be attained.⁶² However, in practice, only about 20% of patients who fail auto-HCT end up undergoing allo-HCT due to rapid progression of disease, age, poor performance status, or lack of suitable donor. It has been proposed that in the coming years, allo-HCT will be utilized less commonly in this setting due to the advent of chimeric antigen receptor T-cell (CAR T) therapy.

CAR T-cell therapy genetically modifies the patient’s own T lymphocytes with a gene that encodes an antigen receptor to direct the T cells against lymphoma cells. Typically, the T cells are genetically modified and expanded in a production facility and then infused back into the patient. Axicabtagene ciloleucel is directed against the CD-19 receptor and has been approved by the US Food and Drug Administration (FDA) for treatment of patients with DLBCL who have failed 2 or more lines of systemic therapy. Use of CAR-T therapy in such patients was examined in a multicenter trial (ZUMA-1), which reported a 54% complete response rate and 52% OS rate at 18 months.⁶³ CAR-T therapy is associated with serious side effects such as cytokine release syndrome, neurological toxicities, and prolonged cytopenias. While there are now some patients with ongoing remission 2 or more years after undergoing CAR-T therapy, it remains uncertain what proportion of patients have been truly cured with this modality. Nevertheless, this new treatment option remains a source of optimism for relapsed and refractory DLBCL patients.

Primary Mediastinal Large B-Cell Lymphoma

Primary mediastinal large B-cell lymphoma (PMBCL) is a form of DLBCL arising in the mediastinum from the thymic B cell. It is an uncommon entity and has clinical and pathologic features distinct from systemic DLBCL.⁶⁴ PMBCL accounts for 2% of all NHLs and about 7% of all DLBCL.²⁰ It typically affects women in the third to fourth decade of life.

Presentation and Prognostic Features

PMBCL usually presents as a locally invasive anterior mediastinal mass, often with a superior vena cava syndrome which may or may not be clinically obvious.⁶⁴ Other presentations include pericardial tamponade, thrombosis of neck veins, and acute airway obstruction. About 80% of patients present with bulky (> 10 cm) stage I or II disease,⁶⁵ with distant spread uncommon on presentation. Morphologically and on GEP, PMBL has a profile more similar to classical Hodgkin lymphoma (cHL) than non-mediastinal DLBCL.⁶⁶ PMBL is distinguished from cHL by immunophenotyping: unlike cHL, PMBCL has pan B cell markers, rarely expresses CD15, and has weak CD30.

Poor prognostic features in PMBCL are Eastern Cooperative Oncology Group (ECOG) performance status greater than 2, pericardial effusion, bulky disease, and elevated serum LDH. The diagnosis of PMBCL can be difficult because the tumor is often encased with extensive fibrosis and necrosis. As a result, a needle biopsy may not yield sufficient tissue, thus making a surgical biopsy often the only viable way to obtain sufficient tissue.

Treatment

Early series suggested that PMBCL is unusually aggressive, with a poor prognosis.⁶⁷ This led to studies using more aggressive chemotherapy regimens (often in combination with mediastinal radiation) as well as upfront auto-HCT.^68–70 The addition of rituximab to treatment regimens significantly improved outcomes in PMBCL. For example, a subgroup analysis of the PMBCL patients in the MinT trial revealed a 3-year event-free survival (EFS) of 78%⁷¹ when rituximab was combined with CHOP. Because of previous reports demonstrating radiosensitivity of PMBL, radiation was traditionally sequenced into treatment regimens for PMBL. However, this is associated with higher long-term toxicities, often a concern in PMBCL patients given that the disease frequently affects younger females, and given that breast tissue will be in the radiation field. For patients with a strong personal or family history of breast cancer or cardiovascular disease, these concerns are even more significant. More recently, the DA-EPOCH-R regimen has been shown to produce very high rates (80%–90%) of long-term DFS, without the need for mediastinal radiation in most cases.^72,73 For patients receiving R-CHOP, consolidation with mediastinal radiation is still commonly given. This approach also leads to high rates of long-term remission and, although utilizing mediastinal radiation, allows for less intensive chemotherapy. Determining which approach is most appropriate for an individual patient requires an assessment of the risks of each treatment option for that patient. A randomized trial by the International Extranodal Lymphoma Study Group (IELSG37) is evaluating whether RT may be safely omitted in PMBCL patients who achieve a complete metabolic response after R-CHOP.

Most relapses of PMBCL occur within the first 1 to 2 years and often present with extranodal disease in various organs. For those with relapsed or refractory disease, high-dose chemotherapy followed by auto-HCT provides 5-year survival rates of 50% to 80%.^74–76 In a phase 1b trial evaluating the role of pembrolizumab in relapsed/refractory patients (KEYNOTE-13), 7 of 17 PMBCL patients achieved responses, with an additional 6 demonstrating stable disease.⁷⁷ This provides an additional option for patients who might be too weak to undergo auto-HCT or for those who relapse following auto-HCT.

Mantle Cell Lymphoma

The name mantle cell lymphoma (MCL) is based on the presumed normal cell counterpart to MCL, which is believed to be found in the mantle zone surrounding germinal center follicles. It represents approximately 6% of all NHL cases in the United States and Europe.⁷⁸ MCL occurs at a median age of 63 to 68 years and has a male predominance.

Presentation and Prognostic Features

Patients can present with a broad spectrum of clinical features, and most patients (70%) present with advanced disease.⁷⁹ Up to one third of patients have B symptoms, with most demonstrating lymphadenopathy and bone marrow involvement. Approximately 25% present with extranodal disease as the primary presentation (eg, GI tract, pleura, breast, or orbits). MCL can involve any part of the GI tract and often presents as polypoid lesions.

Histologically, the pattern of MCL may be diffuse, nodular, mantle zone, or a combination of the these; morphologically, MCL can range from small, more irregular lymphocytes to lymphoblast-like cells. Blastoid and pleomorphic variants of MCL have a higher proliferation index and a more aggressive clinical course than other variants. MCL is characterized by the expression of pan B cell antigens (CD19+, CD20+) with coexpression of the T-cell antigen CD5, lack of CD23 expression, and nuclear expression of cyclin D1. Nuclear staining for cyclin D1 is present in more than 98% of cases.⁸⁰ In rare cases, CD5 or cyclin D1 may be negative.⁸⁰ Most MCL cases have a unique translocation that fuses the immunoglobulin heavy chain gene promoter (14q32) to the promoter of the BCL-1 gene (11q13), which encodes the cyclin D1 protein. This translocation is not unique to MCL and can be present in multiple myeloma as well. Interestingly, cyclin D1 is overproduced in cases lacking t(11:14), likely from other point mutations resulting in its overexpression.⁸¹ Cyclin D1–negative tumors overexpress cyclin D2 or D3, with no apparent difference in clinical behavior or outcome.⁸² In cyclin D1–negative cases, SOX11 expression may help with diagnosis.⁸³ A proliferation rate greater than 30% (as measured by Ki-67 staining), low SOX11 expression, and presence of p53 mutations have all been associated with adverse outcome.

In a minority of cases, MCL follows an indolent clinical course. For the remainder, however, MCL is an aggressive disease that generally requires treatment soon after diagnosis. When initially described in the 1980s and 1990s, treatment of MCL was characterized by low complete response rates, short durations of remission, repeated recurrences, and a median survival in the 2- to 5-year range.⁸⁴ In recent years, intensive regimens incorporating rituximab and high-dose cytarabine with or without auto-HCT have been developed and are associated with high complete response rates and median duration of first remission in the 6- to 9-year range.^85–87 Several prognostic indices have been applied to patients with MCL, including the IPI, the Follicular Lymphoma International Prognostic Index , and the Mantle Cell Lymphoma International Prognostic Index (MIPI). The MIPI was originally described based on a cohort from the period 1996 to 2004,⁸⁸ and subsequently confirmed in a separate cohort of 958 patients with MCL treated on prospective trials between 2004 and 2010.⁸⁹ The MIPI score can identify 3 risk groups with significant survival differences (83%, 63%, and 34% survival at 5 years). A refined version of the MIPI score, the combined MIPI or MIPI-c, incorporates proliferation rate and is better able to stratify patients.⁹⁰ The blastoid variant of MCL follows a more aggressive clinical course and is associated with a high proliferation rate, shorter remissions, and a higher rate of CNS involvement.⁹¹

In most patients, MCL is an aggressive disease with a short OS without treatment. A subset of patients may have a more indolent course,⁹² but unfortunately reliable factors that identify this group at the time of diagnosis are not available. Pretreatment evaluation is as with other lymphomas, with lumbar puncture and MRI of the brain also recommended for patients with the blastoid variant. For those presenting with GI symptoms, endoscopy is recommended as part of the initial evaluation as well.

Treatment

First-line Therapy

For patients under age 65 to 70 years with a good performance status and few comorbidities, an intensive induction regimen (such as R-CHOP/R-DHAP, Maxi-R-CHOP/R-araC, or R-DHAP) followed by consolidation with auto-HCT is commonly given, with a goal of achieving a durable (6–9 year) first remission.^87,93,94 Auto-HCT is now routinely followed by 3 years of maintenance rituximab based on the survival benefit seen in the recent LYSA trial.⁹³ At many centers, auto-HCT in first remission is a standard of care, with the greatest benefit seen in patients who have achieved a complete remission with no more than 2 lines of chemotherapy.⁹⁵ However, there remains some controversy about whether all patients truly benefit from auto-HCT in first remission, and current research efforts are focused on identifying patients most likely to benefit from auto-HCT and incorporation of new agents into first-line regimens. For patients who are not candidates for auto-HCT, bendamustine plus rituximab (BR) or R-CHOP alone or followed by maintenance rituximab is a reasonable approach.⁹⁶ Based on the StiL and BRIGHT trials, BR seems to have less toxicity and higher rates of response with no difference in OS when compared to R-CHOP.^97,98

In summary, dose-intense induction chemotherapy with consolidative auto-HCT results in high rates of long-term remission and can be considered in MCL patients who lack significant comorbidities and who understand the risks and benefits of this approach. For other patients, the less aggressive frontline approaches are more appropriate.

Relapsed/Refractory Disease

Despite initial high response rates, most patients with MCL will eventually relapse. For example, most patients given CHOP or R-CHOP alone as first-line therapy will relapse within 2 years.⁹⁹ In recent years, a number of therapies have emerged for relapsed/refractory MCL; however, the optimal sequencing of these is unclear. FDA-approved options for relapsed/refractory MCL include the proteasome inhibitor bortezomib,^100,101 the BTK inhibitors ibrutinib^102,103 and acalabrutinib,¹⁰⁴ and the immunomodulatory agent lenalidomide.¹⁰⁵

Auto-HCT can be considered for patients who did not undergo auto-HCT as part of first-line therapy and who had a reasonably long first remission.⁹⁵ Allo-HCT has curative potential in MCL with good evidence of a graft-versus-lymphoma effect. With a matched related or matched unrelated donor, the chance for treatment-related mortality is 15% to 25% at 1 to 2 years, with a 50% to 60% chance for long-term PFS. However, given the risk of treatment-related mortality and graft-versus-host disease, this option is typically reserved for patients with early relapse after auto-HCT, multiple relapses, or relatively chemotherapy-unresponsive disease.^95,106 A number of clinical trials for relapsed/refractory MCL are ongoing, and participation in these is encouraged whenever possible.

Burkitt Lymphoma

Burkitt lymphoma is a rare, aggressive and highly curable subtype of NHL. It can occur at any age, although peak incidence is in the first decade of life. There are 3 distinct clinical forms of Burkitt lymphoma.¹⁰⁷ The endemic form is common in African children and commonly involves the jaw and kidneys. The sporadic (nonendemic) form accounts for 1% to 2% of all lymphomas in the United States and Western Europe and usually has an abdominal presentation. The immunodeficiency-associated form is commonly seen in HIV patients with a relatively preserved CD4 cell count.

Patients typically present with rapidly growing masses and tumor lysis syndrome. CNS and bone marrow involvement are common. Burkitt lymphoma cells are high-grade, rapidly proliferating medium-sized cells with a monomorphic appearance. Biopsies show a classic histological appearance known as a “starry sky pattern” due to benign macrophages engulfing debris resulting from apoptosis. It is derived from a germinal center B cell and has distinct oncogenic pathways. Translocations such as t(8;14), t(2;8) or t(8;22) juxtapose the MYC locus with immunoglobulin heavy or light chain loci and result in MYC overexpression. Burkitt lymphoma is typically CD10-positive and BCL-2-negative, with a MYC translocation and a proliferation rate greater than 95%.

With conventional NHL regimens, Burkitt lymphoma had a poor prognosis, with complete remission in the 30% to 70% range and low rates of long-term remission. With the introduction of short-term, dose-intensive, multiagent chemotherapy regimens (adapted from pediatric acute lymphoblastic leukemia [ALL] regimens), the complete remission rate improved to 60% to 90%.¹⁰⁷ Early stage disease (localized or completely resected intra-abdominal disease) can have complete remission rates of 100%, with 2- to 5-year freedom-from-progression rates of 95%. CNS prophylaxis, including high-dose methotrexate, high-dose cytarabine, and intrathecal chemotherapy, is a standard component of Burkitt lymphoma regimens (CNS relapse rates can reach 50% without prophylactic therapy). Crucially, relapse after 1 to 2 years is very rare following complete response to induction therapy. Classically, several intensive regimens have been used for Burkitt lymphoma. In recent years, the most commonly used regimens have been the modified Magrath regimen of R-CODOX-M/IVAC and R-hyperCVAD. DA-EPOCH-R has also been used, typically for older, more frail, or HIV-positive patients. However, at the American Society of Hematology 2017 annual meeting, results from the NCI 9177 trial were presented which validated, in a prospective multi-center fashion, the use of DA-EPOCH-R in all Burkitt lymphoma patients.¹⁰⁸ In NCI 9177, low-risk patients (defined as normal LDH, ECOG performance score 0 or 1, ≤ stage II, and no tumor lesion > 7 cm) received 2 cycles of DA-EPOCH-R without intrathecal therapy followed by PET. If interim PET was negative, low-risk patients then received 1 more cycle of DA-EPOCH-R. High-risk patients with negative brain MRI and CSF cytology/flow cytometry received 2 cycles of DA-EPOCH-R with intrathecal therapy (2 doses per cycle) followed by PET. Unless interim PET showed progression, high-risk patients received 4 additional cycles of DA-EPOCH-R including methotrexate 12 mg intrathecally on days 1 and 5 (8 total doses). With a median follow-up of 36 months, this regimen resulted in an EFS of 85.7%. As expected, patients with CNS, marrow, or peripheral blood involvement fared worse. For those without CNS, marrow, or peripheral blood involvement, the results were excellent, with an EFS of 94.6% compared to 62.8% for those with CNS, bone marrow, or blood involvement at diagnosis.

Although no standard of care has been defined, patients with relapsed/refractory Burkitt lymphoma are often given standard second-line aggressive NHL regimens (eg, R-ICE); for those with chemosensitive disease, auto- or allo-HCT is often pursued, with long-term remissions possible following HCT.¹⁰⁹

Lymphoblastic Lymphoma

Lymphoblastic lymphoma (LBL) is a rare disease postulated to arise from precursor B or T lymphoblasts at varying stages of differentiation. Accounting for approximately 2% of all NHLs, 85% to 90% of all cases have a T-cell phenotype, while B-cell LBL comprises approximately 10% to 15% of cases. LBL and ALL are thought to represent the same disease entity, but LBL has been arbitrarily defined as cases with lymph node or mediastinal disease. Those with significant (> 25%) bone marrow or peripheral blood involvement are classified as ALL.

Precursor T-cell LBL patients are usually adolescent and young males who commonly present with a mediastinal mass and peripheral lymphadenopathy. Precursor B-cell LBL patients are usually older (median age 39 years) with peripheral lymphadenopathy and extranodal involvement. Mediastinal involvement with B-cell LBL is uncommon, and there is no male predominance. LBL has a propensity for dissemination to the bone marrow and CNS.

Morphologically, the tumor cells are medium sized, with a scant cytoplasm and finely dispersed chromatin. Mitotic features and apoptotic bodies are present since it is a high-grade malignancy. The lymphoblasts are typically positive for CD7 and either surface or cytoplasmic CD3. Terminal deoxynucleotidyl transferase expression is a defining feature. Other markers such as CD19, CD22, CD20, CD79a, CD45, and CD10 are variably expressed. Poor prognostic factors in T-cell LBL are female gender, age greater than 35 years, complex cytogenetics, and lack of a matched sibling donor.

Regimens for LBL are based on dose-dense, multi-agent protocols used in ALL. Most of these regimens are characterized by intensive remission-induction chemotherapy, CNS prophylaxis, a phase of consolidation therapy, and a prolonged maintenance phase, often lasting for 12 to 18 months with long-term DFS rates of 40% to 70%.^110,111 High-dose therapy with auto-HCT or allo-HCT in first complete response has been evaluated in an attempt to reduce the incidence of relapse.¹¹² However, the intensity of primary chemotherapy appears to be a stronger determinant of long-term survival than the use of HCT as consolidation. As a result, HCT is not routinely applied to patients in first complete remission following modern induction regimens. After relapse, prognosis is poor, with median survival rates of 6 to 9 months with conventional chemotherapy, although long-term survival rates of 30% and 20%, respectively, are reported after HCT in relapsed and primary refractory disease.¹¹³

Treatment options in relapsed disease are limited. Nelarabine can produce responses in up to 40% of relapsed/refractory LBL/ALL patients.¹¹⁴ For the minority of LBL patients with a B-cell phenotype, emerging options for relapsed/refractory LBL/ALL such as inotuzumab, blinatumomab, or anti-CD19 CAR T-cell therapy should be considered. These are not options for the majority who have a T-cell phenotype, and treatment options for these patients are limited to conventional relapsed/refractory ALL and aggressive NHL regimens.

Summary

Aggressive NHLs are characterized by rapid clinical progression without therapy. However, a significant proportion of patients are cured with appropriate combination chemotherapy or combined modality (chemotherapy + RT) regimens. In contrast, the indolent lymphomas have a relatively good prognosis (median survival of 10 years or longer) but usually are not curable in advanced clinical stages. Overall 5-year survival for aggressive NHLs with current treatment is approximately 50% to 60%, with relapses typically occurring within the first 5 years. Treatment strategies for relapsed patients offer some potential for cure; however, clinical trial participation should be encouraged whenever possible to investigate new approaches for improving outcomes in this patient population.

Introduction

Non-Hodgkin lymphoma (NHL) comprises a wide variety of malignant hematologic disorders with varying clinical and biological features. The more than 60 separate NHL subtypes can be classified according to cell of origin (B cell versus T cell), anatomical location (eg, orbital, testicular, bone, central nervous system), clinical behavior (indolent versus aggressive), histological features, or cytogenetic abnormalities. Although various NHL classification schemes have been used over the years, the World Health Organization (WHO) classification is now widely accepted as the definitive pathologic classification system for lymphoproliferative disorders, incorporating morphologic, immunohistochemical, flow cytometric, cytogenetic, and molecular features.¹ While the pathologic and molecular subclassification of NHL has become increasingly refined in recent years, from a management standpoint, classification based on clinical behavior remains very useful. This approach separates NHL subtypes into indolent versus aggressive categories. Whereas indolent NHLs may remain clinically insignificant for months to years, aggressive B-cell NHLs generally become life-threatening within weeks to months without treatment.

Epidemiology

Data from cancer registries show a steady, unexplainable increase in the incidence of NHL during the second half of the 20th century; the incidence has subsequently plateaued. There was a significant increase in NHL incidence between 1970 and 1995, which has been attributed in part to the HIV epidemic. More than 72,000 new cases of NHL were diagnosed in the United States in 2017, compared to just over 8000 cases of Hodgkin lymphoma, making NHL the sixth most common cancer in adult men and the fifth most common in adult women.² NHL appears to occur more frequently in Western countries than in Asian populations.

Various factors associated with increased risk for B-cell NHL have been identified over the years, including occupational and environmental exposure to certain pesticides and herbicides,³ immunosuppression associated with HIV infection,⁴ autoimmune disorders,⁵ iatrogenically induced immune suppression in the post-transplant and other settings,⁶ family history of NHL,⁷ and a personal history of a prior cancer, including Hodgkin lymphoma and prior NHL.⁸ In terms of infectious agents associated with aggressive B-cell NHLs, Epstein-Barr virus (EBV) has a clear pathogenic role in Burkitt lymphoma, in many cases of post-transplant lymphoproliferative disorders, and in some cases of HIV-related aggressive B-cell lymphoma.⁹ Human herpesvirus-8 viral genomes have been found in virtually all cases of primary effusion lymphomas.¹⁰ Epidemiological studies also have linked hepatitis B and C to increased incidences of certain NHL subtypes,^11–13 including primary hepatic diffuse large B-cell lymphoma (DLBCL). Similarly, Helicobacter pylori has been associated with gastric DLBCL.

Staging and Work-Up

A tissue biopsy is essential in the diagnosis and management of NHL. The most significant disadvantage of fine-needle aspiration cytology is the lack of histologic architecture. The optimal specimen is an excisional biopsy; when this cannot be performed, a core needle biopsy, ideally using a 16-gauge or larger caliber needle, is the next best choice.

The baseline tests appropriate for most cases of newly diagnosed aggressive B-cell NHL are listed in Table 1. Both hepatitis B and C have been associated with increased risk of NHL. In addition, there is a risk of hepatitis B reactivation following certain NHL therapies. A contrast-enhanced computed tomography (CT) scan in addition to positron emission tomography (PET) is useful to define the extent of disease in situations needing greater definition (eg, lymphadenopathy close to the bowel, cervical and supraclavicular nodal involvement, and lymphadenopathy causing thrombosis or compression of nearby structures).¹⁴ In cases where it is apparent that the patient has advanced stage disease (Ann Arbor stage III/IV) based on imaging, bone marrow biopsy is unlikely to alter the treatment plan. For such patients, if the complete blood count is unremarkable, deferral of bone marrow biopsy may be reasonable. For new cases of DLBCL, assessment for MYC translocation by fluorescence in situ hybridization (FISH) is recommended. If a MYC translocation is identified, then testing for BCL2 and BCL6 translocations by FISH should be performed.

Prior to the initiation of treatment, patients should always undergo a thorough cardiac and pulmonary evaluation, especially if the patient will be treated with an anthracycline or mediastinal irradiation. Central nervous system (CNS) evaluation with magnetic resonance imaging (MRI) and lumbar puncture is essential if there are neurological signs or symptoms. In addition, certain anatomical sites including the testicles, paranasal sinuses, kidney, adrenal glands, and epidural space have been associated with increased involvement of the CNS and may warrant MRI evaluation and lumbar puncture. Certain NHL subtypes like Burkitt lymphoma, high-grade NHL with translocations of MYC and BCL-2 or BCL-6 (double-hit lymphoma), blastoid mantle cell lymphoma, and lymphoblastic lymphoma have a high risk of CNS involvement, and patients with these subtypes need CNS evaluation.

The Lugano classification is used to stage patients with NHL.¹⁴ This classification is based on the Ann Arbor staging system and uses the distribution and number of tumor sites to stage disease. In general, this staging system in isolation is of limited value in predicting survival after treatment. However, the Ann Arbor stage does have prognostic impact when incorporated into risk scoring systems such as the International Prognostic Index (IPI). In clinical practice, the Ann Arbor stage is useful primarily to determine eligibility for localized therapy approaches. The absence or presence of systemic symptoms such as fevers, drenching night sweats, or weight loss (> 10% of baseline over 6 months or less) is designated by A or B, respectively.

Diffuse Large B-Cell Lymphoma

DLBCL is the most common lymphoid neoplasm in adults, accounting for about 25% of all NHL cases.² It is increasingly clear that the diagnostic category of DLBCL is quite heterogeneous in terms of morphology, genetics, and biologic behavior. A number of clinicopathologic subtypes of DLBCL exist, such as T cell/histiocyte–rich large B-cell lymphoma, primary mediastinal large B-cell lymphoma, intravascular large B-cell lymphoma, DLBCL associated with chronic inflammation, lymphomatoid granulomatosis, and EBV-positive large B-cell lymphoma, among others. Gene expression profiling (GEP) can distinguish 2 cell of origin DLBCL subtypes: the germinal center B-cell (GCB) and activated B-cell (ABC) subtypes.¹⁵

DLBCL may be primary (de novo) or may arise through the transformation of many different types of low-grade B-cell lymphomas. This latter scenario is referred to as histologic transformation or transformed lymphoma. In some cases, patients may have a previously diagnosed low-grade B-cell NHL; in other cases, both low-grade and aggressive B-cell NHL may be diagnosed concurrently. The presence of elements of both low-grade and aggressive B-cell NHL in the same biopsy specimen is sometimes referred to as a composite lymphoma.

In the United States, incidence varies by ethnicity, with DLBCL being more common in Caucasians than other races.¹⁶ There is a slight male predominance (55%), median age at diagnosis is 65 years,^16,17 and the incidence increases with age.

Presentation, Pathology, and Prognostic Factors

The most common presentation of patients with DLBCL is rapidly enlarging lymphadenopathy, usually in the neck or abdomen. Extranodal/extramedullary presentation is seen in approximately 40% of cases, with the gastrointestinal (GI) tract being the most common site. However, extranodal DLBCL can arise in virtually any tissue.¹⁸ Nodal DLBCL presents with symptoms related to the sites of involvement (eg, shortness of breath or chest pain with mediastinal lymphadenopathy), while extranodal DLBCL typically presents with symptoms secondary to dysfunction at the site of origin. Up to one third of patients present with constitutional symptoms (B symptoms) and more than 50% have elevated serum lactate dehydrogenase (LDH) at diagnosis.¹⁹

Approximately 40% of patients present with stage I/II disease. Of these, only a subset present with stage I, or truly localized disease (defined as that which can be contained within 1 irradiation field). About 60% of patients present with advanced (stage III–IV) disease.²⁰ The bone marrow is involved in about 15% to 30% of cases. DLBCL involvement of the bone marrow is associated with a less favorable prognosis. Patients with DLBCL elsewhere may have low-grade NHL involvement of the bone marrow. Referred to as discordant bone marrow involvement,²¹ this feature does not carry the same poor prognosis associated with transformed disease²² or DLBCL involvement of the bone marrow.²³

DLBCL is defined as a neoplasm of large B-lymphoid cells with a diffuse growth pattern. The proliferative fraction of cells, as determined by Ki-67 staining, is usually greater than 40%, and may even exceed 90%. Lymph nodes usually demonstrate complete effacement of the normal architecture by sheets of atypical lymphoid cells. Tumor cells in DLBCL generally express pan B-cell antigens (CD19, CD20, CD22, CD79a, Pax-5) as well as CD45 and surface immunoglobulin. Between 20% and 37% of DLBCL cases express the BCL-2 protein,²⁴ and about 70% express the BCL-6 protein.²⁵ C-MYC protein expression is seen in a higher percentage (~ 30%–50%) of cases of DLBCL.²⁶

Many factors are associated with outcome in DLBCL. The IPI score was developed in the pre-rituximab era and is a robust prognostic tool. This simple tool uses 5 easily obtained clinical factors (age > 60 years, impaired performance status, elevated LDH, > 1 extranodal site of disease, and stage III/IV disease). By summing these factors, 4 groups with distinct 5-year overall survival (OS) rates ranging from 26% to 73% were identified (Table 2). Subsequently, modifications were made to adjust for age and stage, with the latest iteration being the NCCN (National Comprehensive Cancer Network) IPI.²⁷ This tool uses age, performance status, LDH ratio (relative to the upper limit of normal), a more precise definition for presence of extranodal sites of disease (defined as lymphomatous involvement in the bone marrow, CNS, liver/GI tract, or lung), and Ann Arbor stage to stratify patients into 4 risk groups with significantly different 5-year OS, ranging from 38% to 96% based on the subgroup. Importantly, the NCCN-IPI was derived in a cohort of patients treated with rituximab-based therapy.

Cytogenetic and molecular factors also predict outcome in DLBCL. The ABC subtype distinguished by GEP has consistently been shown to have inferior outcomes with first-line therapy. As GEP is not routinely available in clinical practice, immunohistochemical (IHC) approaches (eg, the Hans algorithm) have been developed that can approximate the GEP subtypes. These IHC approaches have approximately 80% concordance with GEP.²⁸ The 3 most common chromosomal translocations in DLBCL involve BCL-2, BCL-6 and MYC. MYC-rearranged DLBCLs have a less favorable prognosis.^29,30 Cases in which a MYC translocation occurs in combination with a BCL-2 or BCL-6 translocation are commonly referred to as double-hit lymphoma (DHL); cases with all 3 translocations are referred to as triple-hit lymphoma (THL). Both DHL and THL have a worse prognosis with standard DLBCL therapy compared to non-DHL/THL cases. In the 2016 revised WHO classification, DHL and THL are an entity technically distinct from DLBCL, referred to as high-grade B-cell lymphoma.¹ In some cases, MYC and BCL-2 protein overexpression occurs in the absence of chromosomal translocations. Cases in which MYC and BCL-2 are overexpressed (by IHC) are referred to as double expressor lymphoma (DEL), and also have inferior outcome compared with non-DEL DLBCL.^31,32 Interestingly, MYC protein expression alone does not confer inferior outcomes, unlike isolated MYC translocation, which is associated with inferior outcomes.

Treatment

First-Line Therapy

DLBCL is an aggressive disease and, in most cases, survival without treatment can be measured in weeks to months. The advent of combination chemotherapy (CHOP [cyclophosphamide, doxorubicin, vincristine, and prednisone] or CHOP-like regimens) led to disease-free survival (DFS) rates of 35% to 40% at 3 to 5 years.³³ The addition of rituximab to CHOP (R-CHOP) has improved both progression-free surivial (PFS) and OS.^34,35

Treatment options vary for patients with localized (stage I/II) and advanced (stage III/IV) disease. Options for limited-stage DLBCL include an abbreviated course of R-CHOP (3 or 4 cycles) with involved-field radiation therapy (IFRT) versus a full course (6–8 cycles) of R-CHOP without radiation therapy (RT). Most studies comparing combined modality therapy (chemotherapy plus RT) versus chemotherapy alone were conducted in the pre-rituximab era. With the introduction of rituximab, Persky and colleagues³⁶ studied the use of 3 cycles of R-CHOP followed by RT, demonstrating a slightly improved OS of 92% at 4 years as compared to 88% in a historical cohort. The French LYSA/GOELAMS group performed the only direct comparison in the rituximab era (4 cycles of R-CHOP followed by RT versus 4 cycles of R-CHOP followed by 2 additional cycles of R-CHOP) and reported similar outcomes between both arms,³⁷ with OS of 92% in the R-CHOP alone arm and 96% in the R-CHOP + RT arm (nonsignificant difference statistically). IFRT alone is not recommended other than for palliation in patients who cannot tolerate chemotherapy or combined modality therapy. Stage I and II patients with bulky disease (> 10 cm) have a prognosis similar to patients with advanced DLBCL and should be treated aggressively with 6 to 8 cycles of R-CHOP with or without RT.³⁶

For patients with advanced stage disease, a full course of R-CHOP-21 (6–8 cycles given on a 21-day cycle) is the standard of care. This approach results in OS rates of 70% and 60% at 2 and 5 years, respectively. For older adults unable to tolerate full-dose R-CHOP, attenuated versions of R-CHOP with decreased dose density or decreased dose intensity have been developed.³⁸ Numerous randomized trials have attempted to improve upon the results of R-CHOP-21 using strategies such as infusional chemotherapy (DA-EPOCH-R [etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, rituximab]);³⁹ dose-dense therapy (R-CHOP-14);replacement of rituximab with obinutuzuimab;⁴⁰ addition of novel agents such as bortezomib,⁴¹ lenalidomide,⁴² or ibrutinib^43,44 to R-CHOP; and various maintenance strategies such as rituximab, lenalidomide,⁴⁵ enzastaurin,⁴⁶ and everolimus.⁴⁷ Unfortunately, none of these strategies has been shown to improve OS in DLBCL. In part this appears to be due to the fact that inclusion/exclusion criteria for DLBCL trials have been too strict, such that the most severely ill DLBCL patients are typically not included. As a result, the results in the control arms have ended up better than what was expected based on historical data. Efforts are underway to include all patients in future first-line DLBCL studies.

Currently, autologous hematopoietic cell transplantation (auto-HCT) is not routinely used in the initial treatment of DLBCL. In the pre-rituximab era, numerous trials were conducted in DLBCL patients with high and/or high-intermediate risk disease based on the IPI score to determine if outcomes could be improved with high-dose therapy and auto-HCT as consolidation after patients achieved complete remission with first-line therapy. The results of these trials were conflicting. A 2003 meta-analysis of 11 such trials concluded that the results were very heterogeneous and showed no OS benefit.⁴⁸ More recently, the Southwestern Oncology Group published the results of a prospective trial testing the impact of auto-HCT for consolidation of aggressive NHL patients with an IPI score of 3 to 5 who achieved complete remission with first-line therapy with CHOP or R-CHOP. In this study, 75% of the patients had DLBCL and, of the B-cell NHL patients, 47% received R-CHOP. A survival benefit was seen only in the subgroup that had an IPI score of 4 or 5; a subgroup analysis restricted to those receiving R-CHOP as induction was not performed, however.⁴⁹ As a result, this area remains controversial, with most institutions not routinely performing auto-HCT for any DLBCL patients in first complete remission and some institutions considering auto-HCT in first complete remission for patients with an IPI score of 4 or 5. These studies all used the IPI score to identify high-risk patients. It is possible that the use of newer biomarkers or minimal-residual disease analysis will lead to a more robust algorithm for identifying high-risk patients and selecting patients who might benefit from consolidation of first complete remission with auto-HCT.

For patients with DHL or THL, long-term PFS with standard R-CHOP therapy is poor (20% to 40%).^50,51 Treatment with more intensive first-line regimens such as DA-EPOCH-R, R-hyperCVAD (rituximab plus hyperfractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone), or CODOX-M/IVAC±R (cyclophosphamide, vincristine, doxorubicin, high‐dose methotrexate/ifosfamide, etoposide, high‐dose cytarabine ± rituximab), along with CNS prophylaxis, however, has been shown to produce superior outcomes,⁵² with 3-year relapse-free survival rates of 88% compared to 56% for R-CHOP. For patients who achieve a complete response by PET/CT scan after intensive induction, consolidation with auto-HCT has not been shown to improve outcomes based on retrospective analysis. However for DHL/THL patients who achieve complete response after R-CHOP, PFS was improved if auto-HCT was given as consolidation of first remission.⁵³

Patients with DLBCL have an approximately 5% risk of subsequently developing CNS involvement. Historically (in the pre-rituximab era), patients who presented with multiple sites of extranodal disease and/or extensive bone marrow involvement and/or an elevated LDH had an increased risk (up to 20%–30%) of developing CNS involvement. In addition, patients with involvement of certain anatomical sites (testicular, paranasal sinuses, epidural space) had an increased risk of CNS disease. Several algorithms have been proposed to identify patients who should receive prophylactic CNS therapy. One of the most robust tools for this purpose is the CNS-IPI, which is a 6-point score consisting of the 5 IPI elements, plus 1 additional point if the adrenal glands or kidneys are involved. Importantly, the CNS-IPI was developed and validated in patients treated with R-CHOP-like therapy. Subsequent risk of CNS relapse was 0.6%, 3.4%, and 10.2% for those with low-, intermediate- and high-risk CNS-IPI scores, respectively.⁵⁴ A reasonable strategy, therefore, is to perform CNS prophylaxis in those with a CNS-IPI score of 4 to 6. When CNS prophylaxis is used, intrathecal methotrexate or high-dose systemic methotrexate is most frequently given, with high-dose systemic methotrexate favored over intrathecal chemotherapy given that high-dose methotrexate penetrates the brain and spinal cord parenchyma, in addition to treating the cerebrospinal fluid (CSF).⁵⁵ In contrast, intrathecal therapy only treats the CSF and requires repeated lumbar punctures or placement of an Ommaya reservoir. For DLBCL patients who present with active CSF involvement (known as lymphomatous meningitis), intrathecal chemotherapy treatments are typically given 2 or 3 times weekly until the CSF clears, followed by weekly intrathecal treatment for 4 weeks, and then monthly intrathecal treatment for 4 months.⁵⁶ For those with concurrent systemic and brain parenchymal DLBCL, a strategy of alternating R-CHOP with mid-cycle high-dose methotrexate can be successful. In addition, consolidation with high-dose therapy and auto-HCT improved survival in such patients in 1 retrospective series.⁵⁷

Relapsed/Refractory Disease

Between 30% and 40% of patients with advanced stage DLBCL will either fail to attain a remission with primary therapy (referred to as primary induction failure) or will relapse. In general, for those with progressive or relapsed disease, an updated tissue biopsy is recommended. This is especially true for patients who have had prior complete remission and have new lymph node enlargement, or those who have emergence of new sites of disease at the completion of first-line therapy.

Patients with relapsed disease are treated with systemic second-line platinum-based chemoimmunotherapy, with the usual goal of ultimately proceeding to auto-HCT. A number of platinum-based regimens have been used in this setting such as R-ICE, R-DHAP, R-GDP, R-Gem-Ox, and R-ESHAP. None of these regimens has been shown to be superior in terms of efficacy, and the choice of regimen is typically made based on the anticipated tolerance of the patient in light of comorbidities, laboratory studies, and physician preference. In the CORAL study, R-DHAP (rituximab, dexamethasone, high-dose cytarabine, cisplatin) seemed to show superior PFS in patients with the GCB subtype.⁵⁸ However, this was an unplanned subgroup analysis and R-DHAP was associated with higher renal toxicity.

Several studies have demonstrated that long-term PFS can be observed for relapsed/refractory DLBCL patients who respond to second-line therapy and then undergo high-dose therapy with auto-HCT. The Parma trial remains the only published prospective randomized trial performed in relapsed DLBCL comparing a transplant strategy to a non-transplant strategy. This study, performed in the pre-rituximab era, clearly showed a benefit in terms of DFS and OS in favor of auto-HCT versus salvage therapy alone.⁵⁹ The benefit of auto-HCT in patients treated in the rituximab era, even in patients who experience early failure (within 1 year of diagnosis), was confirmed in a retrospective analysis by the Center for International Blood and Marrow Transplant Research. In this study, a 44% 3-year PFS was seen in the early failure cohort versus 52% in the late failure cohort.⁶⁰

Some DLBCL patients are very unlikely to benefit from auto-HCT. The REFINE study focused on patients with primary induction failure or early relapse within 6 months of completing first-line therapy. Among such patients, primary progressive disease (defined as progression while still receiving first-line therapy), a high NCCN-IPI score at relapse, and MYC rearrangement were risk factors for poor PFS following auto-HCT.⁶¹ Patients with 2 or 3 high-risk features had a 2-year OS of 10.7% compared to 74.3% for those without any high-risk features.

Allogeneic HCT (allo-HCT) is a treatment option for relapsed/refractory DLBCL. This option is more commonly considered for patients in whom an autotransplant has failed to achieve durable remission. For properly selected patients in this setting, a long-term PFS in the 30% to 40% range can be attained.⁶² However, in practice, only about 20% of patients who fail auto-HCT end up undergoing allo-HCT due to rapid progression of disease, age, poor performance status, or lack of suitable donor. It has been proposed that in the coming years, allo-HCT will be utilized less commonly in this setting due to the advent of chimeric antigen receptor T-cell (CAR T) therapy.

CAR T-cell therapy genetically modifies the patient’s own T lymphocytes with a gene that encodes an antigen receptor to direct the T cells against lymphoma cells. Typically, the T cells are genetically modified and expanded in a production facility and then infused back into the patient. Axicabtagene ciloleucel is directed against the CD-19 receptor and has been approved by the US Food and Drug Administration (FDA) for treatment of patients with DLBCL who have failed 2 or more lines of systemic therapy. Use of CAR-T therapy in such patients was examined in a multicenter trial (ZUMA-1), which reported a 54% complete response rate and 52% OS rate at 18 months.⁶³ CAR-T therapy is associated with serious side effects such as cytokine release syndrome, neurological toxicities, and prolonged cytopenias. While there are now some patients with ongoing remission 2 or more years after undergoing CAR-T therapy, it remains uncertain what proportion of patients have been truly cured with this modality. Nevertheless, this new treatment option remains a source of optimism for relapsed and refractory DLBCL patients.

Primary Mediastinal Large B-Cell Lymphoma

Primary mediastinal large B-cell lymphoma (PMBCL) is a form of DLBCL arising in the mediastinum from the thymic B cell. It is an uncommon entity and has clinical and pathologic features distinct from systemic DLBCL.⁶⁴ PMBCL accounts for 2% of all NHLs and about 7% of all DLBCL.²⁰ It typically affects women in the third to fourth decade of life.

Presentation and Prognostic Features

PMBCL usually presents as a locally invasive anterior mediastinal mass, often with a superior vena cava syndrome which may or may not be clinically obvious.⁶⁴ Other presentations include pericardial tamponade, thrombosis of neck veins, and acute airway obstruction. About 80% of patients present with bulky (> 10 cm) stage I or II disease,⁶⁵ with distant spread uncommon on presentation. Morphologically and on GEP, PMBL has a profile more similar to classical Hodgkin lymphoma (cHL) than non-mediastinal DLBCL.⁶⁶ PMBL is distinguished from cHL by immunophenotyping: unlike cHL, PMBCL has pan B cell markers, rarely expresses CD15, and has weak CD30.

Poor prognostic features in PMBCL are Eastern Cooperative Oncology Group (ECOG) performance status greater than 2, pericardial effusion, bulky disease, and elevated serum LDH. The diagnosis of PMBCL can be difficult because the tumor is often encased with extensive fibrosis and necrosis. As a result, a needle biopsy may not yield sufficient tissue, thus making a surgical biopsy often the only viable way to obtain sufficient tissue.

Treatment

Early series suggested that PMBCL is unusually aggressive, with a poor prognosis.⁶⁷ This led to studies using more aggressive chemotherapy regimens (often in combination with mediastinal radiation) as well as upfront auto-HCT.^68–70 The addition of rituximab to treatment regimens significantly improved outcomes in PMBCL. For example, a subgroup analysis of the PMBCL patients in the MinT trial revealed a 3-year event-free survival (EFS) of 78%⁷¹ when rituximab was combined with CHOP. Because of previous reports demonstrating radiosensitivity of PMBL, radiation was traditionally sequenced into treatment regimens for PMBL. However, this is associated with higher long-term toxicities, often a concern in PMBCL patients given that the disease frequently affects younger females, and given that breast tissue will be in the radiation field. For patients with a strong personal or family history of breast cancer or cardiovascular disease, these concerns are even more significant. More recently, the DA-EPOCH-R regimen has been shown to produce very high rates (80%–90%) of long-term DFS, without the need for mediastinal radiation in most cases.^72,73 For patients receiving R-CHOP, consolidation with mediastinal radiation is still commonly given. This approach also leads to high rates of long-term remission and, although utilizing mediastinal radiation, allows for less intensive chemotherapy. Determining which approach is most appropriate for an individual patient requires an assessment of the risks of each treatment option for that patient. A randomized trial by the International Extranodal Lymphoma Study Group (IELSG37) is evaluating whether RT may be safely omitted in PMBCL patients who achieve a complete metabolic response after R-CHOP.

Most relapses of PMBCL occur within the first 1 to 2 years and often present with extranodal disease in various organs. For those with relapsed or refractory disease, high-dose chemotherapy followed by auto-HCT provides 5-year survival rates of 50% to 80%.^74–76 In a phase 1b trial evaluating the role of pembrolizumab in relapsed/refractory patients (KEYNOTE-13), 7 of 17 PMBCL patients achieved responses, with an additional 6 demonstrating stable disease.⁷⁷ This provides an additional option for patients who might be too weak to undergo auto-HCT or for those who relapse following auto-HCT.

Mantle Cell Lymphoma

The name mantle cell lymphoma (MCL) is based on the presumed normal cell counterpart to MCL, which is believed to be found in the mantle zone surrounding germinal center follicles. It represents approximately 6% of all NHL cases in the United States and Europe.⁷⁸ MCL occurs at a median age of 63 to 68 years and has a male predominance.

Presentation and Prognostic Features

Patients can present with a broad spectrum of clinical features, and most patients (70%) present with advanced disease.⁷⁹ Up to one third of patients have B symptoms, with most demonstrating lymphadenopathy and bone marrow involvement. Approximately 25% present with extranodal disease as the primary presentation (eg, GI tract, pleura, breast, or orbits). MCL can involve any part of the GI tract and often presents as polypoid lesions.

Histologically, the pattern of MCL may be diffuse, nodular, mantle zone, or a combination of the these; morphologically, MCL can range from small, more irregular lymphocytes to lymphoblast-like cells. Blastoid and pleomorphic variants of MCL have a higher proliferation index and a more aggressive clinical course than other variants. MCL is characterized by the expression of pan B cell antigens (CD19+, CD20+) with coexpression of the T-cell antigen CD5, lack of CD23 expression, and nuclear expression of cyclin D1. Nuclear staining for cyclin D1 is present in more than 98% of cases.⁸⁰ In rare cases, CD5 or cyclin D1 may be negative.⁸⁰ Most MCL cases have a unique translocation that fuses the immunoglobulin heavy chain gene promoter (14q32) to the promoter of the BCL-1 gene (11q13), which encodes the cyclin D1 protein. This translocation is not unique to MCL and can be present in multiple myeloma as well. Interestingly, cyclin D1 is overproduced in cases lacking t(11:14), likely from other point mutations resulting in its overexpression.⁸¹ Cyclin D1–negative tumors overexpress cyclin D2 or D3, with no apparent difference in clinical behavior or outcome.⁸² In cyclin D1–negative cases, SOX11 expression may help with diagnosis.⁸³ A proliferation rate greater than 30% (as measured by Ki-67 staining), low SOX11 expression, and presence of p53 mutations have all been associated with adverse outcome.

In a minority of cases, MCL follows an indolent clinical course. For the remainder, however, MCL is an aggressive disease that generally requires treatment soon after diagnosis. When initially described in the 1980s and 1990s, treatment of MCL was characterized by low complete response rates, short durations of remission, repeated recurrences, and a median survival in the 2- to 5-year range.⁸⁴ In recent years, intensive regimens incorporating rituximab and high-dose cytarabine with or without auto-HCT have been developed and are associated with high complete response rates and median duration of first remission in the 6- to 9-year range.^85–87 Several prognostic indices have been applied to patients with MCL, including the IPI, the Follicular Lymphoma International Prognostic Index , and the Mantle Cell Lymphoma International Prognostic Index (MIPI). The MIPI was originally described based on a cohort from the period 1996 to 2004,⁸⁸ and subsequently confirmed in a separate cohort of 958 patients with MCL treated on prospective trials between 2004 and 2010.⁸⁹ The MIPI score can identify 3 risk groups with significant survival differences (83%, 63%, and 34% survival at 5 years). A refined version of the MIPI score, the combined MIPI or MIPI-c, incorporates proliferation rate and is better able to stratify patients.⁹⁰ The blastoid variant of MCL follows a more aggressive clinical course and is associated with a high proliferation rate, shorter remissions, and a higher rate of CNS involvement.⁹¹

In most patients, MCL is an aggressive disease with a short OS without treatment. A subset of patients may have a more indolent course,⁹² but unfortunately reliable factors that identify this group at the time of diagnosis are not available. Pretreatment evaluation is as with other lymphomas, with lumbar puncture and MRI of the brain also recommended for patients with the blastoid variant. For those presenting with GI symptoms, endoscopy is recommended as part of the initial evaluation as well.

Treatment

First-line Therapy

For patients under age 65 to 70 years with a good performance status and few comorbidities, an intensive induction regimen (such as R-CHOP/R-DHAP, Maxi-R-CHOP/R-araC, or R-DHAP) followed by consolidation with auto-HCT is commonly given, with a goal of achieving a durable (6–9 year) first remission.^87,93,94 Auto-HCT is now routinely followed by 3 years of maintenance rituximab based on the survival benefit seen in the recent LYSA trial.⁹³ At many centers, auto-HCT in first remission is a standard of care, with the greatest benefit seen in patients who have achieved a complete remission with no more than 2 lines of chemotherapy.⁹⁵ However, there remains some controversy about whether all patients truly benefit from auto-HCT in first remission, and current research efforts are focused on identifying patients most likely to benefit from auto-HCT and incorporation of new agents into first-line regimens. For patients who are not candidates for auto-HCT, bendamustine plus rituximab (BR) or R-CHOP alone or followed by maintenance rituximab is a reasonable approach.⁹⁶ Based on the StiL and BRIGHT trials, BR seems to have less toxicity and higher rates of response with no difference in OS when compared to R-CHOP.^97,98

In summary, dose-intense induction chemotherapy with consolidative auto-HCT results in high rates of long-term remission and can be considered in MCL patients who lack significant comorbidities and who understand the risks and benefits of this approach. For other patients, the less aggressive frontline approaches are more appropriate.

Relapsed/Refractory Disease

Despite initial high response rates, most patients with MCL will eventually relapse. For example, most patients given CHOP or R-CHOP alone as first-line therapy will relapse within 2 years.⁹⁹ In recent years, a number of therapies have emerged for relapsed/refractory MCL; however, the optimal sequencing of these is unclear. FDA-approved options for relapsed/refractory MCL include the proteasome inhibitor bortezomib,^100,101 the BTK inhibitors ibrutinib^102,103 and acalabrutinib,¹⁰⁴ and the immunomodulatory agent lenalidomide.¹⁰⁵

Auto-HCT can be considered for patients who did not undergo auto-HCT as part of first-line therapy and who had a reasonably long first remission.⁹⁵ Allo-HCT has curative potential in MCL with good evidence of a graft-versus-lymphoma effect. With a matched related or matched unrelated donor, the chance for treatment-related mortality is 15% to 25% at 1 to 2 years, with a 50% to 60% chance for long-term PFS. However, given the risk of treatment-related mortality and graft-versus-host disease, this option is typically reserved for patients with early relapse after auto-HCT, multiple relapses, or relatively chemotherapy-unresponsive disease.^95,106 A number of clinical trials for relapsed/refractory MCL are ongoing, and participation in these is encouraged whenever possible.

Burkitt Lymphoma

Burkitt lymphoma is a rare, aggressive and highly curable subtype of NHL. It can occur at any age, although peak incidence is in the first decade of life. There are 3 distinct clinical forms of Burkitt lymphoma.¹⁰⁷ The endemic form is common in African children and commonly involves the jaw and kidneys. The sporadic (nonendemic) form accounts for 1% to 2% of all lymphomas in the United States and Western Europe and usually has an abdominal presentation. The immunodeficiency-associated form is commonly seen in HIV patients with a relatively preserved CD4 cell count.

Patients typically present with rapidly growing masses and tumor lysis syndrome. CNS and bone marrow involvement are common. Burkitt lymphoma cells are high-grade, rapidly proliferating medium-sized cells with a monomorphic appearance. Biopsies show a classic histological appearance known as a “starry sky pattern” due to benign macrophages engulfing debris resulting from apoptosis. It is derived from a germinal center B cell and has distinct oncogenic pathways. Translocations such as t(8;14), t(2;8) or t(8;22) juxtapose the MYC locus with immunoglobulin heavy or light chain loci and result in MYC overexpression. Burkitt lymphoma is typically CD10-positive and BCL-2-negative, with a MYC translocation and a proliferation rate greater than 95%.

With conventional NHL regimens, Burkitt lymphoma had a poor prognosis, with complete remission in the 30% to 70% range and low rates of long-term remission. With the introduction of short-term, dose-intensive, multiagent chemotherapy regimens (adapted from pediatric acute lymphoblastic leukemia [ALL] regimens), the complete remission rate improved to 60% to 90%.¹⁰⁷ Early stage disease (localized or completely resected intra-abdominal disease) can have complete remission rates of 100%, with 2- to 5-year freedom-from-progression rates of 95%. CNS prophylaxis, including high-dose methotrexate, high-dose cytarabine, and intrathecal chemotherapy, is a standard component of Burkitt lymphoma regimens (CNS relapse rates can reach 50% without prophylactic therapy). Crucially, relapse after 1 to 2 years is very rare following complete response to induction therapy. Classically, several intensive regimens have been used for Burkitt lymphoma. In recent years, the most commonly used regimens have been the modified Magrath regimen of R-CODOX-M/IVAC and R-hyperCVAD. DA-EPOCH-R has also been used, typically for older, more frail, or HIV-positive patients. However, at the American Society of Hematology 2017 annual meeting, results from the NCI 9177 trial were presented which validated, in a prospective multi-center fashion, the use of DA-EPOCH-R in all Burkitt lymphoma patients.¹⁰⁸ In NCI 9177, low-risk patients (defined as normal LDH, ECOG performance score 0 or 1, ≤ stage II, and no tumor lesion > 7 cm) received 2 cycles of DA-EPOCH-R without intrathecal therapy followed by PET. If interim PET was negative, low-risk patients then received 1 more cycle of DA-EPOCH-R. High-risk patients with negative brain MRI and CSF cytology/flow cytometry received 2 cycles of DA-EPOCH-R with intrathecal therapy (2 doses per cycle) followed by PET. Unless interim PET showed progression, high-risk patients received 4 additional cycles of DA-EPOCH-R including methotrexate 12 mg intrathecally on days 1 and 5 (8 total doses). With a median follow-up of 36 months, this regimen resulted in an EFS of 85.7%. As expected, patients with CNS, marrow, or peripheral blood involvement fared worse. For those without CNS, marrow, or peripheral blood involvement, the results were excellent, with an EFS of 94.6% compared to 62.8% for those with CNS, bone marrow, or blood involvement at diagnosis.

Although no standard of care has been defined, patients with relapsed/refractory Burkitt lymphoma are often given standard second-line aggressive NHL regimens (eg, R-ICE); for those with chemosensitive disease, auto- or allo-HCT is often pursued, with long-term remissions possible following HCT.¹⁰⁹

Lymphoblastic Lymphoma

Lymphoblastic lymphoma (LBL) is a rare disease postulated to arise from precursor B or T lymphoblasts at varying stages of differentiation. Accounting for approximately 2% of all NHLs, 85% to 90% of all cases have a T-cell phenotype, while B-cell LBL comprises approximately 10% to 15% of cases. LBL and ALL are thought to represent the same disease entity, but LBL has been arbitrarily defined as cases with lymph node or mediastinal disease. Those with significant (> 25%) bone marrow or peripheral blood involvement are classified as ALL.

Precursor T-cell LBL patients are usually adolescent and young males who commonly present with a mediastinal mass and peripheral lymphadenopathy. Precursor B-cell LBL patients are usually older (median age 39 years) with peripheral lymphadenopathy and extranodal involvement. Mediastinal involvement with B-cell LBL is uncommon, and there is no male predominance. LBL has a propensity for dissemination to the bone marrow and CNS.

Morphologically, the tumor cells are medium sized, with a scant cytoplasm and finely dispersed chromatin. Mitotic features and apoptotic bodies are present since it is a high-grade malignancy. The lymphoblasts are typically positive for CD7 and either surface or cytoplasmic CD3. Terminal deoxynucleotidyl transferase expression is a defining feature. Other markers such as CD19, CD22, CD20, CD79a, CD45, and CD10 are variably expressed. Poor prognostic factors in T-cell LBL are female gender, age greater than 35 years, complex cytogenetics, and lack of a matched sibling donor.

Regimens for LBL are based on dose-dense, multi-agent protocols used in ALL. Most of these regimens are characterized by intensive remission-induction chemotherapy, CNS prophylaxis, a phase of consolidation therapy, and a prolonged maintenance phase, often lasting for 12 to 18 months with long-term DFS rates of 40% to 70%.^110,111 High-dose therapy with auto-HCT or allo-HCT in first complete response has been evaluated in an attempt to reduce the incidence of relapse.¹¹² However, the intensity of primary chemotherapy appears to be a stronger determinant of long-term survival than the use of HCT as consolidation. As a result, HCT is not routinely applied to patients in first complete remission following modern induction regimens. After relapse, prognosis is poor, with median survival rates of 6 to 9 months with conventional chemotherapy, although long-term survival rates of 30% and 20%, respectively, are reported after HCT in relapsed and primary refractory disease.¹¹³

Treatment options in relapsed disease are limited. Nelarabine can produce responses in up to 40% of relapsed/refractory LBL/ALL patients.¹¹⁴ For the minority of LBL patients with a B-cell phenotype, emerging options for relapsed/refractory LBL/ALL such as inotuzumab, blinatumomab, or anti-CD19 CAR T-cell therapy should be considered. These are not options for the majority who have a T-cell phenotype, and treatment options for these patients are limited to conventional relapsed/refractory ALL and aggressive NHL regimens.

Summary

Aggressive NHLs are characterized by rapid clinical progression without therapy. However, a significant proportion of patients are cured with appropriate combination chemotherapy or combined modality (chemotherapy + RT) regimens. In contrast, the indolent lymphomas have a relatively good prognosis (median survival of 10 years or longer) but usually are not curable in advanced clinical stages. Overall 5-year survival for aggressive NHLs with current treatment is approximately 50% to 60%, with relapses typically occurring within the first 5 years. Treatment strategies for relapsed patients offer some potential for cure; however, clinical trial participation should be encouraged whenever possible to investigate new approaches for improving outcomes in this patient population.

Introduction

Breast cancer is the second leading cause of cancer deaths among women in the United States, according to the SEER database. It is estimated that 1 in 8 women will be diagnosed with breast cancer at some point during their lifetime (12.4% lifetime risk).^1,2 Because breast tumors are clinically and histopathologically heterogeneous, different diagnostic and therapeutic approaches are required for each subtype. Among the subtypes, tumors that are positive for human epidermal growth factor receptor 2 (HER2) account for approximately 15% to 20% of all newly diagnosed localized and metastatic invasive breast tumors.^3,4 Historically, this subset of tumors has been considered the most aggressive due to a higher propensity to relapse and metastasize, translating into poorer prognosis compared with other subtypes.^5–7 However, with the advent of HER2-targeted therapy in the late 1990s, prognosis has significantly improved for both early- and late-stage HER2-positive tumors.⁸

Pathogenesis

The HER2 proto-oncogene belongs to a family of human epidermal growth factor receptors that includes 4 transmembrane tyrosine kinase receptors: HER1 (also commonly known as epidermal growth factor receptor, EGFR), HER2, HER3, and HER4. Another commonly used nomenclature for this family of receptors is ERBB1 to ERBB4. Each of the receptors has a similar structure consisting of a growth factor–binding extracellular domain, a single transmembrane segment, an intracellular protein-tyrosine kinase catalytic domain, and a tyrosine-containing cytoplasmic tail. Activation of the extracellular domain leads to conformational changes that initiate a cascade of reactions resulting in protein kinase activation. ERBB tyrosine receptor kinases subsequently activate several intracellular pathways that are critical for cellular function and survival, including the PI3K-AKT, RAS-MAPK, and mTOR pathways. Hyperactivation or overexpression of these receptors leads to uncontrolled cell growth and proliferation, and eventually cancerogenesis.^9,10

HER2 gene amplification can cause activation of the receptor’s extramembranous domain by way of either dimerization of two HER2 receptors or heterodimerization with other ERBB family receptors, leading to ligand-independent activation of cell signaling (ie, activation in the absence of external growth factors). Besides breast cancer, HER2 protein is overexpressed in several other tumor types, including esophageal and gastric adenocarcinomas, colon and gynecological malignancies, and to a lesser extent in other malignancies.

Biomarker Testing

All patients with newly diagnosed breast cancer should have their tumor tissue submitted for biomarker testing for estrogen receptors (ER), progesterone receptors (PR), and HER2 overexpression, as the result this testing dictates therapy choices. The purpose of HER2 testing is to investigate whether the HER2 gene, located on chromosome 17, is overexpressed or amplified. HER2 status provides the basis for treatment selection, which impacts long-term outcome measures such as recurrence and survival. Routine testing of carcinoma in situ for HER2 expression/amplification is not recommended and has no implication on choice of therapy at this time.

In 2013, the American Society of Clinical Oncology and the College of American Pathologists (ASCO/CAP) updated their clinical guideline recommendations for HER2 testing in breast cancer to improve its accuracy and its utility as a predictive marker.¹¹ There are currently 2 approved modalities for HER2 testing: detection of HER2 protein overexpression by immunohistochemical staining (IHC), and detection of HER2 gene amplification using in-situ hybridization. The results of each type of testing are reported as positive, equivocal, or negative (Table 1).¹¹  IHC uses antibodies against HER2 protein to assess the level of protein expression at the membrane of invasive tumor cells; overexpression of HER2 is established based upon the intensity of cell membrane staining and the number of stained cells. Results are reported as positive for HER2 expression (3+ staining), negative for HER2 expression (0 or 1+ staining), or equivocal for HER2 expression (2+ staining).

Fluorescence in-situ hybridization (FISH) testing assesses for HER2 amplification by determining the number of HER2 signals and chromosome 17 centromere (CEP17) signals, respectively, in a tissue sample. HER2 status is based on the ratio of average HER2 signals to CEP17 signals and the average HER2 signal count per cell. FISH testing is considered positive when there are ≥ 6 copies of HER2 signals per cell or when the HER2/CEP17 ratio is ≥ 2. FISH testing is reported as negative when there are fewer than 4 copies of HER2 per cell and the HER2/CEP17 ratio is < 2. 

Neoadjuvant and Adjuvant Therapy for Locoregional Disease

Case Patient 1

A 56-year-old woman undergoes ultrasound-guided biopsy of a self-palpated breast lump. Pathology shows invasive ductal carcinoma that is ER-positive, PR-negative, and HER2 equivocal by IHC (2+ staining). Follow-up FISH testing shows a HER2/CEP17 ratio of 2.5. The tumor is estimated to be 2 cm in diameter by imaging and exam with no clinically palpable axillary lymphadenopathy. The patient exhibits no constitutional or localized symptoms concerning for metastases.

• What is the recommended management approach for this patient?

According to the ASCO/CAP guidelines, this patient’s tumor qualifies as HER2-positive based upon testing results showing amplification of the gene. This result has important implications for management since nearly all patients with macroscopically invasive HER2-positive tumors should be considered for adjuvant chemotherapy in combination with anti-HER2 therapy. The patient should proceed with upfront tumor resection and sentinel lymph node biopsy. Systemic staging imaging (ie, computed tomography [CT] or bone scan) is not indicated in early stage breast cancer.^12,13 Systemic staging scans are indicated when (1) any anatomical stage III disease is suspected (eg, with involvement of the skin or chest wall, the presence of enlarged matted or fixed axillary lymph nodes, and involvement of nodal stations other than in the axilla), and (2) when symptoms or abnormal laboratory values raise suspicion for distant metastases (eg, unexplained bone pain, unintentional weight loss, elevated serum alkaline phosphatase, and transaminitis).

Case 1 Continued

The patient presents to discuss treatment options after undergoing a lumpectomy and sentinel node biopsy procedure. The pathology report notes a single focus of carcinoma measuring 2 cm with negative sentinel lymph nodes.

• What agents are used for adjuvant therapy in HER2-postive breast cancer?

Nearly all patients with macroscopically invasive (> 1 mm) breast carcinoma should be considered for adjuvant therapy using a regimen that contains a taxane and trastuzumab. However, the benefit may be small for patients with tumors ≤ 5 mm (T1a, N0), so it is important to carefully weigh the risk against the benefit. Among the agents that targeting HER2, only trastuzumab has been shown to improve overall survival (OS) in the adjuvant setting; long-term follow-up data are awaited for other agents.⁸ A trastuzumab biosimilar, trastuzumab-dkst, was recently approved by the US Food and Drug Administration (FDA) for the same indications as trastuzumab.¹⁴ The regimens most commonly used in the adjuvant and neoadjuvant settings for nonmetastatic breast cancer are summarized in Table 2.

Patients with small (≤ 3 cm), node-negative tumors can generally be considered for a reduced-intensity regimen that includes weekly paclitaxel plus trastuzumab. This combination proved efficacious in a single-group, multicenter study that enrolled 406 patients.¹⁵ Paclitaxel and trastuzumab were given once weekly for 12 weeks, followed by trastuzumab, either weekly or every 3 weeks, to complete 1 year of therapy.After a median follow-up of more than 6 years, the rates of distant and locoregional recurrence were 1% and 1.2%, respectively.¹⁶

A combination of docetaxel, carboplatin, and trastuzumab is a nonanthracycline regimen that is also appropriate in this setting, based on the results of the Breast Cancer International Research Group 006 (BCIRG-006) trial.¹⁷ This phase 3 randomized trial enrolled 3222 women with HER2-positive, invasive, high-risk adenocarcinoma. Eligible patients had a T1–3 tumor and either lymph node–negative or –positive disease and were randomly assigned to receive 1 of 3 regimens: group 1 received doxorubicin and cyclophosphamide every 3 weeks for 4 cycles followed by docetaxel every 3 weeks for 4 cycles (AC-T); group 2 received the AC-T regimen in combination with trastuzumab; and group 3 received docetaxel, carboplatin, and trastuzumab once every 3 weeks for 6 cycles (TCH). Groups 2 and 3 also received trastuzumab for an additional 34 weeks to complete 1 year of therapy. Trastuzumab-containing regimens were found to offer superior disease-free survival (DFS) and OS. When comparing the 2 trastuzumab arms after more than 10 years of follow-up, no statistically significant advantage of an anthracycline regimen over a nonanthracycline regimen was found.¹⁸ Furthermore, the anthracycline arm had a fivefold higher incidence of symptomatic congestive heart failure (grades 3 and 4), and the nonanthracycline regimen was associated with a lower incidence of treatment-related leukemia, a clinically significant finding despite not reaching statistical significance due to low overall numbers.

BCIRG-006, NSABP B-31, NCCTG N9831, and HERA are all large randomized trials with consistent results confirming trastuzumab’s role in reducing recurrence and improving survival in HER2-positive breast cancer in the adjuvant settings. The estimated overall benefit from addition of this agent was a 34% to 41% improvement in survival and a 33% to 52% improvement in DFS.^8,17–20

Dual anti-HER2 therapy containing both trastuzumab and pertuzumab should be strongly considered for patients with macroscopic lymph node involvement based on the results of the APHINITY trial.²¹ In this study, the addition of pertuzumab to standard trastuzumab-based therapy led to a significant improvement in invasive-disease-free survival at 3 years. In subgroup analysis, the benefit was restricted to the node-positive group (3-year invasive-disease-free survival rates of 92% in the pertuzumab group versus 90.2% in the placebo group, P = 0.02). Patients with hormone receptor–negative disease derived greater benefit from the addition of pertuzumab. Regimens used in the APHINITY trial included the anti-HER2 agents trastuzumab and pertuzumab in combination with 1 of the following chemotherapy regimens: sequential cyclophosphamide plus either doxorubicin or epirubicin, followed by either 4 cycles of docetaxel or 12 weekly doses of paclitaxel; sequential fluorouracil plus either epirubicin or doxorubicin plus cyclophosphamide (3 or 4 cycles), followed by 3 or 4 cycles of docetaxel or 12 weekly cycles of paclitaxel; or 6 cycles of concurrent docetaxel plus carboplatin.

One-year therapy with neratinib, an oral tyrosine kinase inhibitor of HER2, is now approved by the FDA after completion of trastuzumab in the adjuvant setting, based on the results of the ExteNET trial.²² In this study, patients who had completed trastuzumab within the preceding 12 months, without evidence of recurrence, were randomly assigned to receive either oral neratinib or placebo daily for 1 year. The 2-year DFS rate was 93.9% and 91.6% for the neratinib and placebo groups, respectively. The most common adverse effect of neratinib was diarrhea, with approximately 40% of patients experiencing grade 3 diarrhea. In subgroup analyses, hormone receptor–positive patients derived the most benefit, while hormone receptor–negative patients derived no or marginal benefit.²² OS benefit has not yet been established.²³

Trastuzumab therapy (with pertuzumab if indicated) should be offered for an optimal duration of 12 months (17 cycles, including those given with chemotherapy backbone). A shorter duration of therapy, 6 months, has been shown to be inferior,²⁴ while a longer duration, 24 months, has been shown to provide no additional benefit.²⁵

Finally, sequential addition of anti-estrogen endocrine therapy is indicated for hormone-positive tumors. Endocrine therapy is usually added after completion of the chemotherapy backbone of the regimen, but may be given concurrently with anti-HER2 therapy. If radiation is being administered, endocrine therapy can be given concurrently or started after radiation therapy is completed.

Case 1 Conclusion

The patient can be offered 1 of 2 adjuvant treatment regimens, either TH or TCH (Table 2). Since the patient had lumpectomy, she is an appropriate candidate for adjuvant radiation, which would be started after completion of the chemotherapy backbone (taxane/platinum). Endocrine therapy for at least 5 years should be offered sequentially or concurrently with radiation. Her long-term prognosis is very favorable.

Case Patient 2

A 43-year-old woman presents with a 4-cm breast mass, a separate skin nodule, and palpable matted axillary lymphadenopathy. Biopsies of the breast mass and subcutaneous nodule reveal invasive ductal carcinoma that is ER-negative, PR-negative, and HER2-positive by IHC (3+ staining). Based on clinical findings, the patient is staged as T4b (separate tumor nodule), N2 (matted axillary lymph nodes). Systemic staging with CT scan of the chest, abdomen, and pelvis shows no evidence of distant metastases.

• What is the recommended approach to management for this patient?

Recommendations for neoadjuvant therapy, given before definitive surgery, follow the same path as with other subtypes of breast cancer. Patients with suspected anatomical stage III disease are strongly encouraged to undergo upfront (neoadjuvant) chemotherapy in combination with HER2-targeted agents. In addition, all HER2-positive patients with clinically node-positive disease can be offered neoadjuvant therapy using chemotherapy plus dual anti-HER2 therapy (trastuzumab and pertuzumab), with complete pathological response expected in more than 60% of patients.^26,27 Because this patient has locally advanced disease, especially skin involvement and matted axillary nodes, she should undergo neoadjuvant therapy. Preferred regimens contain both trastuzumab and pertuzumab in combination with cytotoxic chemotherapy. The latter may be given concurrently (nonanthracycline regimens, such as docetaxel plus carboplatin) or sequentially (anthracycline-based regimens), as outlined in Table 2. Administration of anthracyclines and trastuzumab simultaneously is contraindicated due to increased risk of cardiomyopathy.²⁸

Endocrine therapy is not indicated for this patient per the current standard of care because the tumor was ER- and PR-negative. Had the tumor been hormone receptor–positive, endocrine therapy for a minimum of 5 years would have been indicated. Likewise, in the case of hormone receptor–positive disease, 12 months of neratinib therapy after completion of trastuzumab may add further benefit, as shown in the ExteNET trial.^22,23 Neratinib seems to have a propensity to prevent or delay trastuzumab-induced overexpression of estrogen receptors. This is mainly due to hormone receptor/HER2 crosstalk, a potential mechanism of resistance to trastuzumab.^29,30

In addition to the medical therapy options discussed here, this patient would be expected to benefit from adjuvant radiation to the breast and regional lymph nodes, given the presence of T4 disease and bulky adenopathy in the axilla.³¹

Case 2 Conclusion

The patient undergoes neoadjuvant treatment (docetaxel, carboplatin, trastuzumab, and pertuzumab every 21 days for a total of 6 cycles), followed by surgical resection (modified radical mastectomy) that reveals complete pathological response (no residual invasive carcinoma). Subsequently, she receives radiation therapy to the primary tumor site and regional lymph nodes while continuing trastuzumab and pertuzumab for 11 more cycles (17 total). Despite presenting with locally advanced disease, the patient has a favorable overall prognosis due to an excellent pathological response.

• What is the approach to follow-up after completion of primary therapy?

Patients may follow up every 3 to 6 months for clinical evaluation in the first 5 years after completing primary adjuvant therapy. An annual screening mammogram is recommended as well. Body imaging can be done if dictated by symptoms. However, routine CT, positron emission tomography, or bone scans are not recommended as part of follow-up in the absence of symptoms, mainly because of a lack of evidence that such surveillance improves survival.³²

Metastatic HER2-Positive Breast Cancer

Metastatic breast cancer most commonly presents as a distant recurrence of previously treated local disease. However, 6% to 18% of patients have no prior history of breast cancer and present with de novo metastatic disease.^33,34 The most commonly involved distant organs are the skeletal bones, liver, lung, distant lymph node stations, and brain. Compared to other subtypes, HER2-positive tumors have an increased tendency to involve the central nervous system.^35–38 Although metastatic HER2-positive breast cancer is not considered curable, significant improvement in survival has been achieved, and patients with metastatic disease have median survival approaching 5 years.³⁹

Case Presentation 3

A 69-year-old woman with a history of breast cancer 4 years ago presents with new-onset back pain and unintentional weight loss. On exam, she is found to have palpable axillary adenopathy on the same side as her previous cancer. Her initial disease was stage IIB ER-positive and HER2-positive and was treated with chemotherapy, mastectomy, and anastrozole, which the patient is still taking. She undergoes CT scan of the chest, abdomen, and pelvis and radionucleotide bone scan, which show multiple liver and bony lesions suspicious for metastatic disease. Axillary lymph node biopsy confirms recurrent invasive carcinoma that is ER-positive and HER2-positive by IHC (3+).

• What is the approach to management of a patient who presents with symptoms of recurrent HER2-positive disease?

This patient likely has metastatic breast cancer based on the imaging findings. In such cases, a biopsy of the recurrent disease should always be considered, if feasible, to confirm the diagnosis and rule out other etiologies such as different malignances and benign conditions. Hormone-receptor and HER2 testing should also be performed on recurrent disease, since a change in HER2 status can be seen in 15% to 33% of cases.^40–42

Based on data from the phase 3 CLEOPATRA trial, first-line systemic regimens for patients with metastatic breast cancer that is positive for HER2 should consist of a combination of docetaxel, trastuzumab, and pertuzumab.  Compared to placebo, adding pertuzumab yielded superior progression-free survival of 18.4 months (versus 12.4 months for placebo) and an unprecedented OS of 56.5 months (versus 40.8 for placebo).³⁹ Weekly paclitaxel can replace docetaxel with comparable efficacy (Table 3).⁴³

Patients can develop significant neuropathy as well as skin and nail changes after multiple cycles of taxane-based chemotherapy. Therefore, the taxane backbone may be dropped after 6 to 8 cycles, while patients continue the trastuzumab and pertuzumab combination until disease progression or unacceptable toxicity. Some patients may enjoy remarkable long-term survival on “maintenance” anti-HER2 therapy.⁴⁴ Despite lack of high-level evidence, such as from large randomized trials, some experts recommend the addition of a hormone blocker after discontinuation of the taxane in ER-positive tumors.⁴⁵

Premenopausal and perimenopausal women with hormone receptor–positive metastatic disease should be considered for simultaneous ovarian suppression. Ovarian suppression can be accomplished medically using a gonadotropin-releasing hormone agonist (goserelin) or surgically via salpingo-oophorectomy.^46–48

Case 3 Conclusion

The patient receives 6 cycles of docetaxel, trastuzumab, and pertuzumab, after which the docetaxel is discontinued due to neuropathy while she continues the other 2 agents. After 26 months of disease control, the patient is found to have new liver metastatic lesions, indicating progression of disease.

• What therapeutic options are available for this patient?

Patients whose disease progresses after receiving taxane- and trastuzumab-containing regimens are candidates to receive the novel antibody-drug conjugate ado-trastuzumab emtansine (T-DM1). Early progressors (ie, patients with early stage disease who have progression of disease while receiving adjuvant trastuzumab or within 6 months of completion of adjuvant trastuzumab) are also candidates for T-DM1. Treatment usually fits in the second line or beyond based on data from the EMILIA trial, which randomly assigned patients to receive either capecitabine plus lapatinib or T-DM1.^49,50 Progression-free survival in the T-DM1 group was 9.6 months versus 6.4 months for the comparator. Improvement of 4 months in OS persisted with longer follow-up despite a crossover rate of 27%. Furthermore, a significantly higher objective response rate and fewer adverse effects were reported in the T-DM1 patients. Most patients included in the EMILIA trial were pertuzumab-naive. However, the benefit of T-DM1 appears to persist, albeit to a lesser extent, for pertuzumab-pretreated patients.^51,52

Patients in whom treatment fails with 2 or more lines of therapy containing taxane-trastuzumab (with or without pertuzumab) and T-DM1 are candidates to receive a combination of capecitabine and lapatinib, a TKI, in the third line and beyond. Similarly, the combination of capecitabine with trastuzumab in the same settings appears to have equal efficacy.^53,54 Trastuzumab may be continued beyond progression while changing the single-agent chemotherapy drug for subsequent lines of therapy, per ASCO guidelines,⁵⁵ although improvement in OS has not been demonstrated beyond the third line in a large randomized trial (Table 3).

Approved HER2-Targeted Drugs

HER2-directed therapy is implemented in the management of nearly all stages of HER2-positive invasive breast cancer, including early and late stages (Table 4).

Trastuzumab

Trastuzumab was the first anti-HER2 agent to be approved by the FDA in 1998. It is a humanized monoclonal antibody directed against the extracellular domain of the HER2 receptor (domain IV).  Trastuzumab functions by interrupting HER2 signal transduction and by flagging tumor cells for immune destruction.⁵⁶ Cardiotoxicity, usually manifested as left ventricular systolic dysfunction, is the most noteworthy adverse effect of trastuzumab. The most prominent risk factors for cardiomyopathy in patients receiving trastuzumab are low baseline ejection fraction (< 55%), age > 50 years, co-administration and higher cumulative dose of anthracyclines, and increased body mass index and obesity.^57–59 Whether patients receive therapy in the neoadjuvant, adjuvant, or metastatic settings, baseline cardiac function assessment with echocardiogram or multiple-gated acquisition scan is required. While well-designed randomized trials validating the value and frequency of monitoring are lacking, repeated cardiac testing every 3 months is generally recommended for patients undergoing adjuvant therapy. Patients with metastatic disease who are receiving treatment with palliative intent may be monitored less frequently.^60,61

An asymptomatic drop in ejection fraction is the most common manifestation of cardiac toxicity. Other cardiac manifestations have also been reported with much less frequency, including arrhythmias, severe congestive heart failure, ventricular thrombus formation, and even cardiac death. Until monitoring and dose-adjustment guidelines are issued, the guidance provided in the FDA-approved prescribing information should be followed, which recommends holding trastuzumab when there is ≥ 16% absolute reduction in left ventricular ejection fraction (LVEF) from the baseline value; or if the LVEF value is below the institutional lower limit of normal and the drop is ≥ 10%. After holding the drug, cardiac function can be re-evaluated every 4 weeks. In most patients, trastuzumab-induced cardiotoxicity can be reversed by withholding trastuzumab and initiating cardioprotective therapy, although the latter remains controversial. Re-challenging after recovery of ejection fraction is possible and toxicity does not appear to be proportional to cumulative dose. Cardiomyopathy due to trastuzumab therapy is potentially reversible within 6 months in more than 80% of cases.^{28,57,60–63}

Other notable adverse effects of trastuzumab include pulmonary toxicity (such as interstitial lung disease) and infusion reactions (usually during or within 24 hours of first dose).

Pertuzumab

Pertuzumab is another humanized monoclonal antibody directed to a different extracellular domain of the HER2 receptor, the dimerization domain (domain II), which is responsible for heterodimerization of HER2 with other HER receptors, especially HER3. This agent should always be co-administered with trastuzumab as the 2 drugs produce synergistic anti-tumor effect, without competition for the receptor. Activation of HER3, via dimerization with HER2, produces an alternative mechanism of downstream signaling, even in the presence of trastuzumab and in the absence of growth factors (Figure 2). 

Ado-Trastuzumab Emtansine

Ado-trastuzumab emtansine (T-DM1) is an antibody-drug conjugate that combines the monoclonal antibody trastuzumab with the cytotoxic agent DM1 (emtansine), a potent microtubule inhibitor and a derivative of maytansine, in a single structure (Figure 3). 

Lapatinib

Lapatinib is an oral small-molecule tyrosine kinase inhibitor of EGFR (HER1) and HER2 receptors. It is approved in combination with capecitabine for patients with HER2-expressing metastatic breast cancer who previously received trastuzumab, an anthracycline, and a taxane chemotherapy or T-DM1. Lapatinib is also approved in combination with letrozole in postmenopausal women with HER2-positive, hormone receptor–positive metastatic disease, although it is unclear where this regimen would fit in the current schema. It may be considered for patients with hormone receptor–positive disease who are not candidates for therapy with taxane-trastuzumab and T-DM1 or who decline this therapy. Diarrhea is seen in most patients treated with lapatinib and may be severe in 20% of cases when lapatinib is combined with capecitabine. Decreases in LVEF have been reported and cardiac function monitoring at baseline and periodically may be considered.^69,70 Lapatinib is not approved for use in adjuvant settings.

Neratinib

Neratinib is an oral small-molecule irreversible tyrosine kinase inhibitor of HER1, HER2, and HER4. It is currently approved only for extended adjuvant therapy after completion of 1 year of standard trastuzumab therapy. It is given orally every day for 1 year. The main side effect, expected in nearly all patients, is diarrhea, which can be severe in up to 40% of patients and may lead to dehydration and electrolyte imbalance. Diarrhea usually starts early in the course of therapy and can be most intense during the first cycle. Therefore, prophylactic antidiarrheal therapy is recommended to reduce the intensity of diarrhea. Loperamide prophylaxis may be initiated simultaneously for all patients using a tapering schedule. Drug interruption or dose reduction may be required if diarrhea is severe or refractory.^21,71 Neratinib is not FDA-approved in the metastatic settings.

Conclusion

HER2-positive tumors represent a distinct subset(s) of breast tumors with unique pathological and clinical characteristics. Treatment with a combination of cytotoxic chemotherapy and HER2-targeted agents has led to a dramatic improvement in survival for patients with locoregional and advanced disease. Trastuzumab is an integral part of adjuvant therapy for HER2-positive invasive disease. Pertuzumab should be added to trastuzumab in node-positive disease. Neratinib may be considered after completion of trastuzumab therapy in patients with hormone receptor–positive disease. For metastatic HER2-positive breast cancer, a regimen consisting of docetaxel plus trastuzumab and pertuzumab is the standard first-line therapy. Ado-trastuzumab is an ideal next line option for patients whose disease progresses on trastuzumab and taxanes.

Introduction

Breast cancer is the second leading cause of cancer deaths among women in the United States, according to the SEER database. It is estimated that 1 in 8 women will be diagnosed with breast cancer at some point during their lifetime (12.4% lifetime risk).^1,2 Because breast tumors are clinically and histopathologically heterogeneous, different diagnostic and therapeutic approaches are required for each subtype. Among the subtypes, tumors that are positive for human epidermal growth factor receptor 2 (HER2) account for approximately 15% to 20% of all newly diagnosed localized and metastatic invasive breast tumors.^3,4 Historically, this subset of tumors has been considered the most aggressive due to a higher propensity to relapse and metastasize, translating into poorer prognosis compared with other subtypes.^5–7 However, with the advent of HER2-targeted therapy in the late 1990s, prognosis has significantly improved for both early- and late-stage HER2-positive tumors.⁸

Pathogenesis

The HER2 proto-oncogene belongs to a family of human epidermal growth factor receptors that includes 4 transmembrane tyrosine kinase receptors: HER1 (also commonly known as epidermal growth factor receptor, EGFR), HER2, HER3, and HER4. Another commonly used nomenclature for this family of receptors is ERBB1 to ERBB4. Each of the receptors has a similar structure consisting of a growth factor–binding extracellular domain, a single transmembrane segment, an intracellular protein-tyrosine kinase catalytic domain, and a tyrosine-containing cytoplasmic tail. Activation of the extracellular domain leads to conformational changes that initiate a cascade of reactions resulting in protein kinase activation. ERBB tyrosine receptor kinases subsequently activate several intracellular pathways that are critical for cellular function and survival, including the PI3K-AKT, RAS-MAPK, and mTOR pathways. Hyperactivation or overexpression of these receptors leads to uncontrolled cell growth and proliferation, and eventually cancerogenesis.^9,10

HER2 gene amplification can cause activation of the receptor’s extramembranous domain by way of either dimerization of two HER2 receptors or heterodimerization with other ERBB family receptors, leading to ligand-independent activation of cell signaling (ie, activation in the absence of external growth factors). Besides breast cancer, HER2 protein is overexpressed in several other tumor types, including esophageal and gastric adenocarcinomas, colon and gynecological malignancies, and to a lesser extent in other malignancies.

Biomarker Testing

All patients with newly diagnosed breast cancer should have their tumor tissue submitted for biomarker testing for estrogen receptors (ER), progesterone receptors (PR), and HER2 overexpression, as the result this testing dictates therapy choices. The purpose of HER2 testing is to investigate whether the HER2 gene, located on chromosome 17, is overexpressed or amplified. HER2 status provides the basis for treatment selection, which impacts long-term outcome measures such as recurrence and survival. Routine testing of carcinoma in situ for HER2 expression/amplification is not recommended and has no implication on choice of therapy at this time.

In 2013, the American Society of Clinical Oncology and the College of American Pathologists (ASCO/CAP) updated their clinical guideline recommendations for HER2 testing in breast cancer to improve its accuracy and its utility as a predictive marker.¹¹ There are currently 2 approved modalities for HER2 testing: detection of HER2 protein overexpression by immunohistochemical staining (IHC), and detection of HER2 gene amplification using in-situ hybridization. The results of each type of testing are reported as positive, equivocal, or negative (Table 1).¹¹  IHC uses antibodies against HER2 protein to assess the level of protein expression at the membrane of invasive tumor cells; overexpression of HER2 is established based upon the intensity of cell membrane staining and the number of stained cells. Results are reported as positive for HER2 expression (3+ staining), negative for HER2 expression (0 or 1+ staining), or equivocal for HER2 expression (2+ staining).

Fluorescence in-situ hybridization (FISH) testing assesses for HER2 amplification by determining the number of HER2 signals and chromosome 17 centromere (CEP17) signals, respectively, in a tissue sample. HER2 status is based on the ratio of average HER2 signals to CEP17 signals and the average HER2 signal count per cell. FISH testing is considered positive when there are ≥ 6 copies of HER2 signals per cell or when the HER2/CEP17 ratio is ≥ 2. FISH testing is reported as negative when there are fewer than 4 copies of HER2 per cell and the HER2/CEP17 ratio is < 2. 

Neoadjuvant and Adjuvant Therapy for Locoregional Disease

Case Patient 1

A 56-year-old woman undergoes ultrasound-guided biopsy of a self-palpated breast lump. Pathology shows invasive ductal carcinoma that is ER-positive, PR-negative, and HER2 equivocal by IHC (2+ staining). Follow-up FISH testing shows a HER2/CEP17 ratio of 2.5. The tumor is estimated to be 2 cm in diameter by imaging and exam with no clinically palpable axillary lymphadenopathy. The patient exhibits no constitutional or localized symptoms concerning for metastases.

• What is the recommended management approach for this patient?

According to the ASCO/CAP guidelines, this patient’s tumor qualifies as HER2-positive based upon testing results showing amplification of the gene. This result has important implications for management since nearly all patients with macroscopically invasive HER2-positive tumors should be considered for adjuvant chemotherapy in combination with anti-HER2 therapy. The patient should proceed with upfront tumor resection and sentinel lymph node biopsy. Systemic staging imaging (ie, computed tomography [CT] or bone scan) is not indicated in early stage breast cancer.^12,13 Systemic staging scans are indicated when (1) any anatomical stage III disease is suspected (eg, with involvement of the skin or chest wall, the presence of enlarged matted or fixed axillary lymph nodes, and involvement of nodal stations other than in the axilla), and (2) when symptoms or abnormal laboratory values raise suspicion for distant metastases (eg, unexplained bone pain, unintentional weight loss, elevated serum alkaline phosphatase, and transaminitis).

Case 1 Continued

The patient presents to discuss treatment options after undergoing a lumpectomy and sentinel node biopsy procedure. The pathology report notes a single focus of carcinoma measuring 2 cm with negative sentinel lymph nodes.

• What agents are used for adjuvant therapy in HER2-postive breast cancer?

Nearly all patients with macroscopically invasive (> 1 mm) breast carcinoma should be considered for adjuvant therapy using a regimen that contains a taxane and trastuzumab. However, the benefit may be small for patients with tumors ≤ 5 mm (T1a, N0), so it is important to carefully weigh the risk against the benefit. Among the agents that targeting HER2, only trastuzumab has been shown to improve overall survival (OS) in the adjuvant setting; long-term follow-up data are awaited for other agents.⁸ A trastuzumab biosimilar, trastuzumab-dkst, was recently approved by the US Food and Drug Administration (FDA) for the same indications as trastuzumab.¹⁴ The regimens most commonly used in the adjuvant and neoadjuvant settings for nonmetastatic breast cancer are summarized in Table 2.

Patients with small (≤ 3 cm), node-negative tumors can generally be considered for a reduced-intensity regimen that includes weekly paclitaxel plus trastuzumab. This combination proved efficacious in a single-group, multicenter study that enrolled 406 patients.¹⁵ Paclitaxel and trastuzumab were given once weekly for 12 weeks, followed by trastuzumab, either weekly or every 3 weeks, to complete 1 year of therapy.After a median follow-up of more than 6 years, the rates of distant and locoregional recurrence were 1% and 1.2%, respectively.¹⁶

A combination of docetaxel, carboplatin, and trastuzumab is a nonanthracycline regimen that is also appropriate in this setting, based on the results of the Breast Cancer International Research Group 006 (BCIRG-006) trial.¹⁷ This phase 3 randomized trial enrolled 3222 women with HER2-positive, invasive, high-risk adenocarcinoma. Eligible patients had a T1–3 tumor and either lymph node–negative or –positive disease and were randomly assigned to receive 1 of 3 regimens: group 1 received doxorubicin and cyclophosphamide every 3 weeks for 4 cycles followed by docetaxel every 3 weeks for 4 cycles (AC-T); group 2 received the AC-T regimen in combination with trastuzumab; and group 3 received docetaxel, carboplatin, and trastuzumab once every 3 weeks for 6 cycles (TCH). Groups 2 and 3 also received trastuzumab for an additional 34 weeks to complete 1 year of therapy. Trastuzumab-containing regimens were found to offer superior disease-free survival (DFS) and OS. When comparing the 2 trastuzumab arms after more than 10 years of follow-up, no statistically significant advantage of an anthracycline regimen over a nonanthracycline regimen was found.¹⁸ Furthermore, the anthracycline arm had a fivefold higher incidence of symptomatic congestive heart failure (grades 3 and 4), and the nonanthracycline regimen was associated with a lower incidence of treatment-related leukemia, a clinically significant finding despite not reaching statistical significance due to low overall numbers.

BCIRG-006, NSABP B-31, NCCTG N9831, and HERA are all large randomized trials with consistent results confirming trastuzumab’s role in reducing recurrence and improving survival in HER2-positive breast cancer in the adjuvant settings. The estimated overall benefit from addition of this agent was a 34% to 41% improvement in survival and a 33% to 52% improvement in DFS.^8,17–20

Dual anti-HER2 therapy containing both trastuzumab and pertuzumab should be strongly considered for patients with macroscopic lymph node involvement based on the results of the APHINITY trial.²¹ In this study, the addition of pertuzumab to standard trastuzumab-based therapy led to a significant improvement in invasive-disease-free survival at 3 years. In subgroup analysis, the benefit was restricted to the node-positive group (3-year invasive-disease-free survival rates of 92% in the pertuzumab group versus 90.2% in the placebo group, P = 0.02). Patients with hormone receptor–negative disease derived greater benefit from the addition of pertuzumab. Regimens used in the APHINITY trial included the anti-HER2 agents trastuzumab and pertuzumab in combination with 1 of the following chemotherapy regimens: sequential cyclophosphamide plus either doxorubicin or epirubicin, followed by either 4 cycles of docetaxel or 12 weekly doses of paclitaxel; sequential fluorouracil plus either epirubicin or doxorubicin plus cyclophosphamide (3 or 4 cycles), followed by 3 or 4 cycles of docetaxel or 12 weekly cycles of paclitaxel; or 6 cycles of concurrent docetaxel plus carboplatin.

One-year therapy with neratinib, an oral tyrosine kinase inhibitor of HER2, is now approved by the FDA after completion of trastuzumab in the adjuvant setting, based on the results of the ExteNET trial.²² In this study, patients who had completed trastuzumab within the preceding 12 months, without evidence of recurrence, were randomly assigned to receive either oral neratinib or placebo daily for 1 year. The 2-year DFS rate was 93.9% and 91.6% for the neratinib and placebo groups, respectively. The most common adverse effect of neratinib was diarrhea, with approximately 40% of patients experiencing grade 3 diarrhea. In subgroup analyses, hormone receptor–positive patients derived the most benefit, while hormone receptor–negative patients derived no or marginal benefit.²² OS benefit has not yet been established.²³

Trastuzumab therapy (with pertuzumab if indicated) should be offered for an optimal duration of 12 months (17 cycles, including those given with chemotherapy backbone). A shorter duration of therapy, 6 months, has been shown to be inferior,²⁴ while a longer duration, 24 months, has been shown to provide no additional benefit.²⁵

Finally, sequential addition of anti-estrogen endocrine therapy is indicated for hormone-positive tumors. Endocrine therapy is usually added after completion of the chemotherapy backbone of the regimen, but may be given concurrently with anti-HER2 therapy. If radiation is being administered, endocrine therapy can be given concurrently or started after radiation therapy is completed.

Case 1 Conclusion

The patient can be offered 1 of 2 adjuvant treatment regimens, either TH or TCH (Table 2). Since the patient had lumpectomy, she is an appropriate candidate for adjuvant radiation, which would be started after completion of the chemotherapy backbone (taxane/platinum). Endocrine therapy for at least 5 years should be offered sequentially or concurrently with radiation. Her long-term prognosis is very favorable.

Case Patient 2

A 43-year-old woman presents with a 4-cm breast mass, a separate skin nodule, and palpable matted axillary lymphadenopathy. Biopsies of the breast mass and subcutaneous nodule reveal invasive ductal carcinoma that is ER-negative, PR-negative, and HER2-positive by IHC (3+ staining). Based on clinical findings, the patient is staged as T4b (separate tumor nodule), N2 (matted axillary lymph nodes). Systemic staging with CT scan of the chest, abdomen, and pelvis shows no evidence of distant metastases.

• What is the recommended approach to management for this patient?

Recommendations for neoadjuvant therapy, given before definitive surgery, follow the same path as with other subtypes of breast cancer. Patients with suspected anatomical stage III disease are strongly encouraged to undergo upfront (neoadjuvant) chemotherapy in combination with HER2-targeted agents. In addition, all HER2-positive patients with clinically node-positive disease can be offered neoadjuvant therapy using chemotherapy plus dual anti-HER2 therapy (trastuzumab and pertuzumab), with complete pathological response expected in more than 60% of patients.^26,27 Because this patient has locally advanced disease, especially skin involvement and matted axillary nodes, she should undergo neoadjuvant therapy. Preferred regimens contain both trastuzumab and pertuzumab in combination with cytotoxic chemotherapy. The latter may be given concurrently (nonanthracycline regimens, such as docetaxel plus carboplatin) or sequentially (anthracycline-based regimens), as outlined in Table 2. Administration of anthracyclines and trastuzumab simultaneously is contraindicated due to increased risk of cardiomyopathy.²⁸

Endocrine therapy is not indicated for this patient per the current standard of care because the tumor was ER- and PR-negative. Had the tumor been hormone receptor–positive, endocrine therapy for a minimum of 5 years would have been indicated. Likewise, in the case of hormone receptor–positive disease, 12 months of neratinib therapy after completion of trastuzumab may add further benefit, as shown in the ExteNET trial.^22,23 Neratinib seems to have a propensity to prevent or delay trastuzumab-induced overexpression of estrogen receptors. This is mainly due to hormone receptor/HER2 crosstalk, a potential mechanism of resistance to trastuzumab.^29,30

In addition to the medical therapy options discussed here, this patient would be expected to benefit from adjuvant radiation to the breast and regional lymph nodes, given the presence of T4 disease and bulky adenopathy in the axilla.³¹

Case 2 Conclusion

The patient undergoes neoadjuvant treatment (docetaxel, carboplatin, trastuzumab, and pertuzumab every 21 days for a total of 6 cycles), followed by surgical resection (modified radical mastectomy) that reveals complete pathological response (no residual invasive carcinoma). Subsequently, she receives radiation therapy to the primary tumor site and regional lymph nodes while continuing trastuzumab and pertuzumab for 11 more cycles (17 total). Despite presenting with locally advanced disease, the patient has a favorable overall prognosis due to an excellent pathological response.

• What is the approach to follow-up after completion of primary therapy?

Patients may follow up every 3 to 6 months for clinical evaluation in the first 5 years after completing primary adjuvant therapy. An annual screening mammogram is recommended as well. Body imaging can be done if dictated by symptoms. However, routine CT, positron emission tomography, or bone scans are not recommended as part of follow-up in the absence of symptoms, mainly because of a lack of evidence that such surveillance improves survival.³²

Metastatic HER2-Positive Breast Cancer

Metastatic breast cancer most commonly presents as a distant recurrence of previously treated local disease. However, 6% to 18% of patients have no prior history of breast cancer and present with de novo metastatic disease.^33,34 The most commonly involved distant organs are the skeletal bones, liver, lung, distant lymph node stations, and brain. Compared to other subtypes, HER2-positive tumors have an increased tendency to involve the central nervous system.^35–38 Although metastatic HER2-positive breast cancer is not considered curable, significant improvement in survival has been achieved, and patients with metastatic disease have median survival approaching 5 years.³⁹

Case Presentation 3

A 69-year-old woman with a history of breast cancer 4 years ago presents with new-onset back pain and unintentional weight loss. On exam, she is found to have palpable axillary adenopathy on the same side as her previous cancer. Her initial disease was stage IIB ER-positive and HER2-positive and was treated with chemotherapy, mastectomy, and anastrozole, which the patient is still taking. She undergoes CT scan of the chest, abdomen, and pelvis and radionucleotide bone scan, which show multiple liver and bony lesions suspicious for metastatic disease. Axillary lymph node biopsy confirms recurrent invasive carcinoma that is ER-positive and HER2-positive by IHC (3+).

• What is the approach to management of a patient who presents with symptoms of recurrent HER2-positive disease?

This patient likely has metastatic breast cancer based on the imaging findings. In such cases, a biopsy of the recurrent disease should always be considered, if feasible, to confirm the diagnosis and rule out other etiologies such as different malignances and benign conditions. Hormone-receptor and HER2 testing should also be performed on recurrent disease, since a change in HER2 status can be seen in 15% to 33% of cases.^40–42

Based on data from the phase 3 CLEOPATRA trial, first-line systemic regimens for patients with metastatic breast cancer that is positive for HER2 should consist of a combination of docetaxel, trastuzumab, and pertuzumab.  Compared to placebo, adding pertuzumab yielded superior progression-free survival of 18.4 months (versus 12.4 months for placebo) and an unprecedented OS of 56.5 months (versus 40.8 for placebo).³⁹ Weekly paclitaxel can replace docetaxel with comparable efficacy (Table 3).⁴³

Patients can develop significant neuropathy as well as skin and nail changes after multiple cycles of taxane-based chemotherapy. Therefore, the taxane backbone may be dropped after 6 to 8 cycles, while patients continue the trastuzumab and pertuzumab combination until disease progression or unacceptable toxicity. Some patients may enjoy remarkable long-term survival on “maintenance” anti-HER2 therapy.⁴⁴ Despite lack of high-level evidence, such as from large randomized trials, some experts recommend the addition of a hormone blocker after discontinuation of the taxane in ER-positive tumors.⁴⁵

Premenopausal and perimenopausal women with hormone receptor–positive metastatic disease should be considered for simultaneous ovarian suppression. Ovarian suppression can be accomplished medically using a gonadotropin-releasing hormone agonist (goserelin) or surgically via salpingo-oophorectomy.^46–48

Case 3 Conclusion

The patient receives 6 cycles of docetaxel, trastuzumab, and pertuzumab, after which the docetaxel is discontinued due to neuropathy while she continues the other 2 agents. After 26 months of disease control, the patient is found to have new liver metastatic lesions, indicating progression of disease.

• What therapeutic options are available for this patient?

Patients whose disease progresses after receiving taxane- and trastuzumab-containing regimens are candidates to receive the novel antibody-drug conjugate ado-trastuzumab emtansine (T-DM1). Early progressors (ie, patients with early stage disease who have progression of disease while receiving adjuvant trastuzumab or within 6 months of completion of adjuvant trastuzumab) are also candidates for T-DM1. Treatment usually fits in the second line or beyond based on data from the EMILIA trial, which randomly assigned patients to receive either capecitabine plus lapatinib or T-DM1.^49,50 Progression-free survival in the T-DM1 group was 9.6 months versus 6.4 months for the comparator. Improvement of 4 months in OS persisted with longer follow-up despite a crossover rate of 27%. Furthermore, a significantly higher objective response rate and fewer adverse effects were reported in the T-DM1 patients. Most patients included in the EMILIA trial were pertuzumab-naive. However, the benefit of T-DM1 appears to persist, albeit to a lesser extent, for pertuzumab-pretreated patients.^51,52

Patients in whom treatment fails with 2 or more lines of therapy containing taxane-trastuzumab (with or without pertuzumab) and T-DM1 are candidates to receive a combination of capecitabine and lapatinib, a TKI, in the third line and beyond. Similarly, the combination of capecitabine with trastuzumab in the same settings appears to have equal efficacy.^53,54 Trastuzumab may be continued beyond progression while changing the single-agent chemotherapy drug for subsequent lines of therapy, per ASCO guidelines,⁵⁵ although improvement in OS has not been demonstrated beyond the third line in a large randomized trial (Table 3).

Approved HER2-Targeted Drugs

HER2-directed therapy is implemented in the management of nearly all stages of HER2-positive invasive breast cancer, including early and late stages (Table 4).

Trastuzumab

Trastuzumab was the first anti-HER2 agent to be approved by the FDA in 1998. It is a humanized monoclonal antibody directed against the extracellular domain of the HER2 receptor (domain IV).  Trastuzumab functions by interrupting HER2 signal transduction and by flagging tumor cells for immune destruction.⁵⁶ Cardiotoxicity, usually manifested as left ventricular systolic dysfunction, is the most noteworthy adverse effect of trastuzumab. The most prominent risk factors for cardiomyopathy in patients receiving trastuzumab are low baseline ejection fraction (< 55%), age > 50 years, co-administration and higher cumulative dose of anthracyclines, and increased body mass index and obesity.^57–59 Whether patients receive therapy in the neoadjuvant, adjuvant, or metastatic settings, baseline cardiac function assessment with echocardiogram or multiple-gated acquisition scan is required. While well-designed randomized trials validating the value and frequency of monitoring are lacking, repeated cardiac testing every 3 months is generally recommended for patients undergoing adjuvant therapy. Patients with metastatic disease who are receiving treatment with palliative intent may be monitored less frequently.^60,61

An asymptomatic drop in ejection fraction is the most common manifestation of cardiac toxicity. Other cardiac manifestations have also been reported with much less frequency, including arrhythmias, severe congestive heart failure, ventricular thrombus formation, and even cardiac death. Until monitoring and dose-adjustment guidelines are issued, the guidance provided in the FDA-approved prescribing information should be followed, which recommends holding trastuzumab when there is ≥ 16% absolute reduction in left ventricular ejection fraction (LVEF) from the baseline value; or if the LVEF value is below the institutional lower limit of normal and the drop is ≥ 10%. After holding the drug, cardiac function can be re-evaluated every 4 weeks. In most patients, trastuzumab-induced cardiotoxicity can be reversed by withholding trastuzumab and initiating cardioprotective therapy, although the latter remains controversial. Re-challenging after recovery of ejection fraction is possible and toxicity does not appear to be proportional to cumulative dose. Cardiomyopathy due to trastuzumab therapy is potentially reversible within 6 months in more than 80% of cases.^{28,57,60–63}

Other notable adverse effects of trastuzumab include pulmonary toxicity (such as interstitial lung disease) and infusion reactions (usually during or within 24 hours of first dose).

Pertuzumab

Pertuzumab is another humanized monoclonal antibody directed to a different extracellular domain of the HER2 receptor, the dimerization domain (domain II), which is responsible for heterodimerization of HER2 with other HER receptors, especially HER3. This agent should always be co-administered with trastuzumab as the 2 drugs produce synergistic anti-tumor effect, without competition for the receptor. Activation of HER3, via dimerization with HER2, produces an alternative mechanism of downstream signaling, even in the presence of trastuzumab and in the absence of growth factors (Figure 2). 

Ado-Trastuzumab Emtansine

Ado-trastuzumab emtansine (T-DM1) is an antibody-drug conjugate that combines the monoclonal antibody trastuzumab with the cytotoxic agent DM1 (emtansine), a potent microtubule inhibitor and a derivative of maytansine, in a single structure (Figure 3). 

Lapatinib

Lapatinib is an oral small-molecule tyrosine kinase inhibitor of EGFR (HER1) and HER2 receptors. It is approved in combination with capecitabine for patients with HER2-expressing metastatic breast cancer who previously received trastuzumab, an anthracycline, and a taxane chemotherapy or T-DM1. Lapatinib is also approved in combination with letrozole in postmenopausal women with HER2-positive, hormone receptor–positive metastatic disease, although it is unclear where this regimen would fit in the current schema. It may be considered for patients with hormone receptor–positive disease who are not candidates for therapy with taxane-trastuzumab and T-DM1 or who decline this therapy. Diarrhea is seen in most patients treated with lapatinib and may be severe in 20% of cases when lapatinib is combined with capecitabine. Decreases in LVEF have been reported and cardiac function monitoring at baseline and periodically may be considered.^69,70 Lapatinib is not approved for use in adjuvant settings.

Neratinib

Neratinib is an oral small-molecule irreversible tyrosine kinase inhibitor of HER1, HER2, and HER4. It is currently approved only for extended adjuvant therapy after completion of 1 year of standard trastuzumab therapy. It is given orally every day for 1 year. The main side effect, expected in nearly all patients, is diarrhea, which can be severe in up to 40% of patients and may lead to dehydration and electrolyte imbalance. Diarrhea usually starts early in the course of therapy and can be most intense during the first cycle. Therefore, prophylactic antidiarrheal therapy is recommended to reduce the intensity of diarrhea. Loperamide prophylaxis may be initiated simultaneously for all patients using a tapering schedule. Drug interruption or dose reduction may be required if diarrhea is severe or refractory.^21,71 Neratinib is not FDA-approved in the metastatic settings.

Conclusion

HER2-positive tumors represent a distinct subset(s) of breast tumors with unique pathological and clinical characteristics. Treatment with a combination of cytotoxic chemotherapy and HER2-targeted agents has led to a dramatic improvement in survival for patients with locoregional and advanced disease. Trastuzumab is an integral part of adjuvant therapy for HER2-positive invasive disease. Pertuzumab should be added to trastuzumab in node-positive disease. Neratinib may be considered after completion of trastuzumab therapy in patients with hormone receptor–positive disease. For metastatic HER2-positive breast cancer, a regimen consisting of docetaxel plus trastuzumab and pertuzumab is the standard first-line therapy. Ado-trastuzumab is an ideal next line option for patients whose disease progresses on trastuzumab and taxanes.

Introduction

Breast cancer is the second leading cause of cancer deaths among women in the United States, according to the SEER database. It is estimated that 1 in 8 women will be diagnosed with breast cancer at some point during their lifetime (12.4% lifetime risk).^1,2 Because breast tumors are clinically and histopathologically heterogeneous, different diagnostic and therapeutic approaches are required for each subtype. Among the subtypes, tumors that are positive for human epidermal growth factor receptor 2 (HER2) account for approximately 15% to 20% of all newly diagnosed localized and metastatic invasive breast tumors.^3,4 Historically, this subset of tumors has been considered the most aggressive due to a higher propensity to relapse and metastasize, translating into poorer prognosis compared with other subtypes.^5–7 However, with the advent of HER2-targeted therapy in the late 1990s, prognosis has significantly improved for both early- and late-stage HER2-positive tumors.⁸

Pathogenesis

The HER2 proto-oncogene belongs to a family of human epidermal growth factor receptors that includes 4 transmembrane tyrosine kinase receptors: HER1 (also commonly known as epidermal growth factor receptor, EGFR), HER2, HER3, and HER4. Another commonly used nomenclature for this family of receptors is ERBB1 to ERBB4. Each of the receptors has a similar structure consisting of a growth factor–binding extracellular domain, a single transmembrane segment, an intracellular protein-tyrosine kinase catalytic domain, and a tyrosine-containing cytoplasmic tail. Activation of the extracellular domain leads to conformational changes that initiate a cascade of reactions resulting in protein kinase activation. ERBB tyrosine receptor kinases subsequently activate several intracellular pathways that are critical for cellular function and survival, including the PI3K-AKT, RAS-MAPK, and mTOR pathways. Hyperactivation or overexpression of these receptors leads to uncontrolled cell growth and proliferation, and eventually cancerogenesis.^9,10

HER2 gene amplification can cause activation of the receptor’s extramembranous domain by way of either dimerization of two HER2 receptors or heterodimerization with other ERBB family receptors, leading to ligand-independent activation of cell signaling (ie, activation in the absence of external growth factors). Besides breast cancer, HER2 protein is overexpressed in several other tumor types, including esophageal and gastric adenocarcinomas, colon and gynecological malignancies, and to a lesser extent in other malignancies.

Biomarker Testing

All patients with newly diagnosed breast cancer should have their tumor tissue submitted for biomarker testing for estrogen receptors (ER), progesterone receptors (PR), and HER2 overexpression, as the result this testing dictates therapy choices. The purpose of HER2 testing is to investigate whether the HER2 gene, located on chromosome 17, is overexpressed or amplified. HER2 status provides the basis for treatment selection, which impacts long-term outcome measures such as recurrence and survival. Routine testing of carcinoma in situ for HER2 expression/amplification is not recommended and has no implication on choice of therapy at this time.

In 2013, the American Society of Clinical Oncology and the College of American Pathologists (ASCO/CAP) updated their clinical guideline recommendations for HER2 testing in breast cancer to improve its accuracy and its utility as a predictive marker.¹¹ There are currently 2 approved modalities for HER2 testing: detection of HER2 protein overexpression by immunohistochemical staining (IHC), and detection of HER2 gene amplification using in-situ hybridization. The results of each type of testing are reported as positive, equivocal, or negative (Table 1).¹¹  IHC uses antibodies against HER2 protein to assess the level of protein expression at the membrane of invasive tumor cells; overexpression of HER2 is established based upon the intensity of cell membrane staining and the number of stained cells. Results are reported as positive for HER2 expression (3+ staining), negative for HER2 expression (0 or 1+ staining), or equivocal for HER2 expression (2+ staining).

Fluorescence in-situ hybridization (FISH) testing assesses for HER2 amplification by determining the number of HER2 signals and chromosome 17 centromere (CEP17) signals, respectively, in a tissue sample. HER2 status is based on the ratio of average HER2 signals to CEP17 signals and the average HER2 signal count per cell. FISH testing is considered positive when there are ≥ 6 copies of HER2 signals per cell or when the HER2/CEP17 ratio is ≥ 2. FISH testing is reported as negative when there are fewer than 4 copies of HER2 per cell and the HER2/CEP17 ratio is < 2. 

Neoadjuvant and Adjuvant Therapy for Locoregional Disease

Case Patient 1

A 56-year-old woman undergoes ultrasound-guided biopsy of a self-palpated breast lump. Pathology shows invasive ductal carcinoma that is ER-positive, PR-negative, and HER2 equivocal by IHC (2+ staining). Follow-up FISH testing shows a HER2/CEP17 ratio of 2.5. The tumor is estimated to be 2 cm in diameter by imaging and exam with no clinically palpable axillary lymphadenopathy. The patient exhibits no constitutional or localized symptoms concerning for metastases.

• What is the recommended management approach for this patient?

According to the ASCO/CAP guidelines, this patient’s tumor qualifies as HER2-positive based upon testing results showing amplification of the gene. This result has important implications for management since nearly all patients with macroscopically invasive HER2-positive tumors should be considered for adjuvant chemotherapy in combination with anti-HER2 therapy. The patient should proceed with upfront tumor resection and sentinel lymph node biopsy. Systemic staging imaging (ie, computed tomography [CT] or bone scan) is not indicated in early stage breast cancer.^12,13 Systemic staging scans are indicated when (1) any anatomical stage III disease is suspected (eg, with involvement of the skin or chest wall, the presence of enlarged matted or fixed axillary lymph nodes, and involvement of nodal stations other than in the axilla), and (2) when symptoms or abnormal laboratory values raise suspicion for distant metastases (eg, unexplained bone pain, unintentional weight loss, elevated serum alkaline phosphatase, and transaminitis).

Case 1 Continued

The patient presents to discuss treatment options after undergoing a lumpectomy and sentinel node biopsy procedure. The pathology report notes a single focus of carcinoma measuring 2 cm with negative sentinel lymph nodes.

• What agents are used for adjuvant therapy in HER2-postive breast cancer?

Nearly all patients with macroscopically invasive (> 1 mm) breast carcinoma should be considered for adjuvant therapy using a regimen that contains a taxane and trastuzumab. However, the benefit may be small for patients with tumors ≤ 5 mm (T1a, N0), so it is important to carefully weigh the risk against the benefit. Among the agents that targeting HER2, only trastuzumab has been shown to improve overall survival (OS) in the adjuvant setting; long-term follow-up data are awaited for other agents.⁸ A trastuzumab biosimilar, trastuzumab-dkst, was recently approved by the US Food and Drug Administration (FDA) for the same indications as trastuzumab.¹⁴ The regimens most commonly used in the adjuvant and neoadjuvant settings for nonmetastatic breast cancer are summarized in Table 2.

Patients with small (≤ 3 cm), node-negative tumors can generally be considered for a reduced-intensity regimen that includes weekly paclitaxel plus trastuzumab. This combination proved efficacious in a single-group, multicenter study that enrolled 406 patients.¹⁵ Paclitaxel and trastuzumab were given once weekly for 12 weeks, followed by trastuzumab, either weekly or every 3 weeks, to complete 1 year of therapy.After a median follow-up of more than 6 years, the rates of distant and locoregional recurrence were 1% and 1.2%, respectively.¹⁶

A combination of docetaxel, carboplatin, and trastuzumab is a nonanthracycline regimen that is also appropriate in this setting, based on the results of the Breast Cancer International Research Group 006 (BCIRG-006) trial.¹⁷ This phase 3 randomized trial enrolled 3222 women with HER2-positive, invasive, high-risk adenocarcinoma. Eligible patients had a T1–3 tumor and either lymph node–negative or –positive disease and were randomly assigned to receive 1 of 3 regimens: group 1 received doxorubicin and cyclophosphamide every 3 weeks for 4 cycles followed by docetaxel every 3 weeks for 4 cycles (AC-T); group 2 received the AC-T regimen in combination with trastuzumab; and group 3 received docetaxel, carboplatin, and trastuzumab once every 3 weeks for 6 cycles (TCH). Groups 2 and 3 also received trastuzumab for an additional 34 weeks to complete 1 year of therapy. Trastuzumab-containing regimens were found to offer superior disease-free survival (DFS) and OS. When comparing the 2 trastuzumab arms after more than 10 years of follow-up, no statistically significant advantage of an anthracycline regimen over a nonanthracycline regimen was found.¹⁸ Furthermore, the anthracycline arm had a fivefold higher incidence of symptomatic congestive heart failure (grades 3 and 4), and the nonanthracycline regimen was associated with a lower incidence of treatment-related leukemia, a clinically significant finding despite not reaching statistical significance due to low overall numbers.

BCIRG-006, NSABP B-31, NCCTG N9831, and HERA are all large randomized trials with consistent results confirming trastuzumab’s role in reducing recurrence and improving survival in HER2-positive breast cancer in the adjuvant settings. The estimated overall benefit from addition of this agent was a 34% to 41% improvement in survival and a 33% to 52% improvement in DFS.^8,17–20

Dual anti-HER2 therapy containing both trastuzumab and pertuzumab should be strongly considered for patients with macroscopic lymph node involvement based on the results of the APHINITY trial.²¹ In this study, the addition of pertuzumab to standard trastuzumab-based therapy led to a significant improvement in invasive-disease-free survival at 3 years. In subgroup analysis, the benefit was restricted to the node-positive group (3-year invasive-disease-free survival rates of 92% in the pertuzumab group versus 90.2% in the placebo group, P = 0.02). Patients with hormone receptor–negative disease derived greater benefit from the addition of pertuzumab. Regimens used in the APHINITY trial included the anti-HER2 agents trastuzumab and pertuzumab in combination with 1 of the following chemotherapy regimens: sequential cyclophosphamide plus either doxorubicin or epirubicin, followed by either 4 cycles of docetaxel or 12 weekly doses of paclitaxel; sequential fluorouracil plus either epirubicin or doxorubicin plus cyclophosphamide (3 or 4 cycles), followed by 3 or 4 cycles of docetaxel or 12 weekly cycles of paclitaxel; or 6 cycles of concurrent docetaxel plus carboplatin.

One-year therapy with neratinib, an oral tyrosine kinase inhibitor of HER2, is now approved by the FDA after completion of trastuzumab in the adjuvant setting, based on the results of the ExteNET trial.²² In this study, patients who had completed trastuzumab within the preceding 12 months, without evidence of recurrence, were randomly assigned to receive either oral neratinib or placebo daily for 1 year. The 2-year DFS rate was 93.9% and 91.6% for the neratinib and placebo groups, respectively. The most common adverse effect of neratinib was diarrhea, with approximately 40% of patients experiencing grade 3 diarrhea. In subgroup analyses, hormone receptor–positive patients derived the most benefit, while hormone receptor–negative patients derived no or marginal benefit.²² OS benefit has not yet been established.²³

Trastuzumab therapy (with pertuzumab if indicated) should be offered for an optimal duration of 12 months (17 cycles, including those given with chemotherapy backbone). A shorter duration of therapy, 6 months, has been shown to be inferior,²⁴ while a longer duration, 24 months, has been shown to provide no additional benefit.²⁵

Finally, sequential addition of anti-estrogen endocrine therapy is indicated for hormone-positive tumors. Endocrine therapy is usually added after completion of the chemotherapy backbone of the regimen, but may be given concurrently with anti-HER2 therapy. If radiation is being administered, endocrine therapy can be given concurrently or started after radiation therapy is completed.

Case 1 Conclusion

The patient can be offered 1 of 2 adjuvant treatment regimens, either TH or TCH (Table 2). Since the patient had lumpectomy, she is an appropriate candidate for adjuvant radiation, which would be started after completion of the chemotherapy backbone (taxane/platinum). Endocrine therapy for at least 5 years should be offered sequentially or concurrently with radiation. Her long-term prognosis is very favorable.

Case Patient 2

A 43-year-old woman presents with a 4-cm breast mass, a separate skin nodule, and palpable matted axillary lymphadenopathy. Biopsies of the breast mass and subcutaneous nodule reveal invasive ductal carcinoma that is ER-negative, PR-negative, and HER2-positive by IHC (3+ staining). Based on clinical findings, the patient is staged as T4b (separate tumor nodule), N2 (matted axillary lymph nodes). Systemic staging with CT scan of the chest, abdomen, and pelvis shows no evidence of distant metastases.

• What is the recommended approach to management for this patient?

Recommendations for neoadjuvant therapy, given before definitive surgery, follow the same path as with other subtypes of breast cancer. Patients with suspected anatomical stage III disease are strongly encouraged to undergo upfront (neoadjuvant) chemotherapy in combination with HER2-targeted agents. In addition, all HER2-positive patients with clinically node-positive disease can be offered neoadjuvant therapy using chemotherapy plus dual anti-HER2 therapy (trastuzumab and pertuzumab), with complete pathological response expected in more than 60% of patients.^26,27 Because this patient has locally advanced disease, especially skin involvement and matted axillary nodes, she should undergo neoadjuvant therapy. Preferred regimens contain both trastuzumab and pertuzumab in combination with cytotoxic chemotherapy. The latter may be given concurrently (nonanthracycline regimens, such as docetaxel plus carboplatin) or sequentially (anthracycline-based regimens), as outlined in Table 2. Administration of anthracyclines and trastuzumab simultaneously is contraindicated due to increased risk of cardiomyopathy.²⁸

Endocrine therapy is not indicated for this patient per the current standard of care because the tumor was ER- and PR-negative. Had the tumor been hormone receptor–positive, endocrine therapy for a minimum of 5 years would have been indicated. Likewise, in the case of hormone receptor–positive disease, 12 months of neratinib therapy after completion of trastuzumab may add further benefit, as shown in the ExteNET trial.^22,23 Neratinib seems to have a propensity to prevent or delay trastuzumab-induced overexpression of estrogen receptors. This is mainly due to hormone receptor/HER2 crosstalk, a potential mechanism of resistance to trastuzumab.^29,30

In addition to the medical therapy options discussed here, this patient would be expected to benefit from adjuvant radiation to the breast and regional lymph nodes, given the presence of T4 disease and bulky adenopathy in the axilla.³¹

Case 2 Conclusion

The patient undergoes neoadjuvant treatment (docetaxel, carboplatin, trastuzumab, and pertuzumab every 21 days for a total of 6 cycles), followed by surgical resection (modified radical mastectomy) that reveals complete pathological response (no residual invasive carcinoma). Subsequently, she receives radiation therapy to the primary tumor site and regional lymph nodes while continuing trastuzumab and pertuzumab for 11 more cycles (17 total). Despite presenting with locally advanced disease, the patient has a favorable overall prognosis due to an excellent pathological response.

• What is the approach to follow-up after completion of primary therapy?

Patients may follow up every 3 to 6 months for clinical evaluation in the first 5 years after completing primary adjuvant therapy. An annual screening mammogram is recommended as well. Body imaging can be done if dictated by symptoms. However, routine CT, positron emission tomography, or bone scans are not recommended as part of follow-up in the absence of symptoms, mainly because of a lack of evidence that such surveillance improves survival.³²

Metastatic HER2-Positive Breast Cancer

Metastatic breast cancer most commonly presents as a distant recurrence of previously treated local disease. However, 6% to 18% of patients have no prior history of breast cancer and present with de novo metastatic disease.^33,34 The most commonly involved distant organs are the skeletal bones, liver, lung, distant lymph node stations, and brain. Compared to other subtypes, HER2-positive tumors have an increased tendency to involve the central nervous system.^35–38 Although metastatic HER2-positive breast cancer is not considered curable, significant improvement in survival has been achieved, and patients with metastatic disease have median survival approaching 5 years.³⁹

Case Presentation 3

A 69-year-old woman with a history of breast cancer 4 years ago presents with new-onset back pain and unintentional weight loss. On exam, she is found to have palpable axillary adenopathy on the same side as her previous cancer. Her initial disease was stage IIB ER-positive and HER2-positive and was treated with chemotherapy, mastectomy, and anastrozole, which the patient is still taking. She undergoes CT scan of the chest, abdomen, and pelvis and radionucleotide bone scan, which show multiple liver and bony lesions suspicious for metastatic disease. Axillary lymph node biopsy confirms recurrent invasive carcinoma that is ER-positive and HER2-positive by IHC (3+).

• What is the approach to management of a patient who presents with symptoms of recurrent HER2-positive disease?

This patient likely has metastatic breast cancer based on the imaging findings. In such cases, a biopsy of the recurrent disease should always be considered, if feasible, to confirm the diagnosis and rule out other etiologies such as different malignances and benign conditions. Hormone-receptor and HER2 testing should also be performed on recurrent disease, since a change in HER2 status can be seen in 15% to 33% of cases.^40–42

Based on data from the phase 3 CLEOPATRA trial, first-line systemic regimens for patients with metastatic breast cancer that is positive for HER2 should consist of a combination of docetaxel, trastuzumab, and pertuzumab.  Compared to placebo, adding pertuzumab yielded superior progression-free survival of 18.4 months (versus 12.4 months for placebo) and an unprecedented OS of 56.5 months (versus 40.8 for placebo).³⁹ Weekly paclitaxel can replace docetaxel with comparable efficacy (Table 3).⁴³

Patients can develop significant neuropathy as well as skin and nail changes after multiple cycles of taxane-based chemotherapy. Therefore, the taxane backbone may be dropped after 6 to 8 cycles, while patients continue the trastuzumab and pertuzumab combination until disease progression or unacceptable toxicity. Some patients may enjoy remarkable long-term survival on “maintenance” anti-HER2 therapy.⁴⁴ Despite lack of high-level evidence, such as from large randomized trials, some experts recommend the addition of a hormone blocker after discontinuation of the taxane in ER-positive tumors.⁴⁵

Premenopausal and perimenopausal women with hormone receptor–positive metastatic disease should be considered for simultaneous ovarian suppression. Ovarian suppression can be accomplished medically using a gonadotropin-releasing hormone agonist (goserelin) or surgically via salpingo-oophorectomy.^46–48

Case 3 Conclusion

The patient receives 6 cycles of docetaxel, trastuzumab, and pertuzumab, after which the docetaxel is discontinued due to neuropathy while she continues the other 2 agents. After 26 months of disease control, the patient is found to have new liver metastatic lesions, indicating progression of disease.

• What therapeutic options are available for this patient?

Patients whose disease progresses after receiving taxane- and trastuzumab-containing regimens are candidates to receive the novel antibody-drug conjugate ado-trastuzumab emtansine (T-DM1). Early progressors (ie, patients with early stage disease who have progression of disease while receiving adjuvant trastuzumab or within 6 months of completion of adjuvant trastuzumab) are also candidates for T-DM1. Treatment usually fits in the second line or beyond based on data from the EMILIA trial, which randomly assigned patients to receive either capecitabine plus lapatinib or T-DM1.^49,50 Progression-free survival in the T-DM1 group was 9.6 months versus 6.4 months for the comparator. Improvement of 4 months in OS persisted with longer follow-up despite a crossover rate of 27%. Furthermore, a significantly higher objective response rate and fewer adverse effects were reported in the T-DM1 patients. Most patients included in the EMILIA trial were pertuzumab-naive. However, the benefit of T-DM1 appears to persist, albeit to a lesser extent, for pertuzumab-pretreated patients.^51,52

Patients in whom treatment fails with 2 or more lines of therapy containing taxane-trastuzumab (with or without pertuzumab) and T-DM1 are candidates to receive a combination of capecitabine and lapatinib, a TKI, in the third line and beyond. Similarly, the combination of capecitabine with trastuzumab in the same settings appears to have equal efficacy.^53,54 Trastuzumab may be continued beyond progression while changing the single-agent chemotherapy drug for subsequent lines of therapy, per ASCO guidelines,⁵⁵ although improvement in OS has not been demonstrated beyond the third line in a large randomized trial (Table 3).

Approved HER2-Targeted Drugs

HER2-directed therapy is implemented in the management of nearly all stages of HER2-positive invasive breast cancer, including early and late stages (Table 4).

Trastuzumab

Trastuzumab was the first anti-HER2 agent to be approved by the FDA in 1998. It is a humanized monoclonal antibody directed against the extracellular domain of the HER2 receptor (domain IV).  Trastuzumab functions by interrupting HER2 signal transduction and by flagging tumor cells for immune destruction.⁵⁶ Cardiotoxicity, usually manifested as left ventricular systolic dysfunction, is the most noteworthy adverse effect of trastuzumab. The most prominent risk factors for cardiomyopathy in patients receiving trastuzumab are low baseline ejection fraction (< 55%), age > 50 years, co-administration and higher cumulative dose of anthracyclines, and increased body mass index and obesity.^57–59 Whether patients receive therapy in the neoadjuvant, adjuvant, or metastatic settings, baseline cardiac function assessment with echocardiogram or multiple-gated acquisition scan is required. While well-designed randomized trials validating the value and frequency of monitoring are lacking, repeated cardiac testing every 3 months is generally recommended for patients undergoing adjuvant therapy. Patients with metastatic disease who are receiving treatment with palliative intent may be monitored less frequently.^60,61

An asymptomatic drop in ejection fraction is the most common manifestation of cardiac toxicity. Other cardiac manifestations have also been reported with much less frequency, including arrhythmias, severe congestive heart failure, ventricular thrombus formation, and even cardiac death. Until monitoring and dose-adjustment guidelines are issued, the guidance provided in the FDA-approved prescribing information should be followed, which recommends holding trastuzumab when there is ≥ 16% absolute reduction in left ventricular ejection fraction (LVEF) from the baseline value; or if the LVEF value is below the institutional lower limit of normal and the drop is ≥ 10%. After holding the drug, cardiac function can be re-evaluated every 4 weeks. In most patients, trastuzumab-induced cardiotoxicity can be reversed by withholding trastuzumab and initiating cardioprotective therapy, although the latter remains controversial. Re-challenging after recovery of ejection fraction is possible and toxicity does not appear to be proportional to cumulative dose. Cardiomyopathy due to trastuzumab therapy is potentially reversible within 6 months in more than 80% of cases.^{28,57,60–63}

Other notable adverse effects of trastuzumab include pulmonary toxicity (such as interstitial lung disease) and infusion reactions (usually during or within 24 hours of first dose).

Pertuzumab

Pertuzumab is another humanized monoclonal antibody directed to a different extracellular domain of the HER2 receptor, the dimerization domain (domain II), which is responsible for heterodimerization of HER2 with other HER receptors, especially HER3. This agent should always be co-administered with trastuzumab as the 2 drugs produce synergistic anti-tumor effect, without competition for the receptor. Activation of HER3, via dimerization with HER2, produces an alternative mechanism of downstream signaling, even in the presence of trastuzumab and in the absence of growth factors (Figure 2). 

Ado-Trastuzumab Emtansine

Ado-trastuzumab emtansine (T-DM1) is an antibody-drug conjugate that combines the monoclonal antibody trastuzumab with the cytotoxic agent DM1 (emtansine), a potent microtubule inhibitor and a derivative of maytansine, in a single structure (Figure 3). 

Lapatinib

Lapatinib is an oral small-molecule tyrosine kinase inhibitor of EGFR (HER1) and HER2 receptors. It is approved in combination with capecitabine for patients with HER2-expressing metastatic breast cancer who previously received trastuzumab, an anthracycline, and a taxane chemotherapy or T-DM1. Lapatinib is also approved in combination with letrozole in postmenopausal women with HER2-positive, hormone receptor–positive metastatic disease, although it is unclear where this regimen would fit in the current schema. It may be considered for patients with hormone receptor–positive disease who are not candidates for therapy with taxane-trastuzumab and T-DM1 or who decline this therapy. Diarrhea is seen in most patients treated with lapatinib and may be severe in 20% of cases when lapatinib is combined with capecitabine. Decreases in LVEF have been reported and cardiac function monitoring at baseline and periodically may be considered.^69,70 Lapatinib is not approved for use in adjuvant settings.

Neratinib

Neratinib is an oral small-molecule irreversible tyrosine kinase inhibitor of HER1, HER2, and HER4. It is currently approved only for extended adjuvant therapy after completion of 1 year of standard trastuzumab therapy. It is given orally every day for 1 year. The main side effect, expected in nearly all patients, is diarrhea, which can be severe in up to 40% of patients and may lead to dehydration and electrolyte imbalance. Diarrhea usually starts early in the course of therapy and can be most intense during the first cycle. Therefore, prophylactic antidiarrheal therapy is recommended to reduce the intensity of diarrhea. Loperamide prophylaxis may be initiated simultaneously for all patients using a tapering schedule. Drug interruption or dose reduction may be required if diarrhea is severe or refractory.^21,71 Neratinib is not FDA-approved in the metastatic settings.

Conclusion

HER2-positive tumors represent a distinct subset(s) of breast tumors with unique pathological and clinical characteristics. Treatment with a combination of cytotoxic chemotherapy and HER2-targeted agents has led to a dramatic improvement in survival for patients with locoregional and advanced disease. Trastuzumab is an integral part of adjuvant therapy for HER2-positive invasive disease. Pertuzumab should be added to trastuzumab in node-positive disease. Neratinib may be considered after completion of trastuzumab therapy in patients with hormone receptor–positive disease. For metastatic HER2-positive breast cancer, a regimen consisting of docetaxel plus trastuzumab and pertuzumab is the standard first-line therapy. Ado-trastuzumab is an ideal next line option for patients whose disease progresses on trastuzumab and taxanes.

More than a third of American adults use complementary and alternative medicine.¹ Unfortunately, the public’s enthusiasm for herbal products is not always consistent with the scientific evidence supporting their use. In part one of this series, we discussed the studies that have been done on capsaicin, butterbur, green tea, and peppermint. In this installment, we outline the research on 5 additional remedies: turmeric/curcumin, which may be of benefit in ulcerative colitis; chamomile, which appears to offer relief to patients with anxiety; rosemary, which may help treat alopecia; as well as coffee and cocoa, which may have some cardiovascular benefits (TABLE).

Turmeric/curcumin

Overview

Turmeric (Curcuma longa), a relative of ginger, has been used for 4000 years to treat a variety of conditions.^2,3 Curcumin is the yellow pigment isolated from the rhizomes of Curcuma longa, commonly known as turmeric.³ Turmeric powder contains 5% curcumin, which is the main biologically active compound. Although it grows in many tropical locations, most turmeric is grown in India, where it is used as a main ingredient in curry. The roots and bulbs of turmeric that are used in medicine are generally boiled and dried, which results in a yellow powder.

Turmeric has been used in both Ayurvedic and Chinese medicine for its anti-inflammatory properties, in the treatment of digestive and liver problems, to fight infections, and to help heal skin diseases and wounds.^3-7

Functional GI disorders. A recent review noted that curcumin has been shown in several preclinical studies and uncontrolled clinical trials to have effects on gut inflammation, gut permeability, and the brain-gut axis, especially in functional GI disorders.⁷ A double-blind, placebo-controlled study from 1989 found that turmeric reduced symptoms of bloating and gas in subjects suffering from undifferentiated dyspepsia.⁸

Ulcerative colitis (UC). A 2012 Cochrane review noted that curcumin appears to be a safe and effective therapy for maintenance of remission in quiescent UC when given as adjunctive therapy along with mesalamine or sulfasalazine.⁹ In a 2015 randomized controlled trial (RCT), the addition of curcumin to mesalamine therapy was superior to the combination of placebo and mesalamine in inducing clinical and endoscopic remission in patients with mild-to-moderate active UC, producing no apparent adverse effects.¹⁰

Osteoarthritis (OA). Because of turmeric’s ability to reduce inflammation, it may help relieve OA pain.³ Clinical evidence is scant for the anti-arthritic efficacy of turmeric dietary supplements, although animal studies indicate that turmeric prevents inflammation through regulation of NF-kappaB-regulated genes that regulate the immune and inflammatory response.⁶ Inflammatory cell influx, joint levels of prostaglandin E2, and periarticular osteoclast formation were also inhibited by turmeric extract treatment.⁶

A 2013 review of turmeric for OA concluded that observational studies and in vitro results are promising for the use of curcumin for OA, but well-designed clinical studies were lacking and are needed to support the efficacy of curcumin in OA patients.¹¹ How­ever, in a 2014 randomized trial of 367 patients, turmeric appeared to be similar in efficacy to ibuprofen for the treatment of pain and disability in adults with knee OA.¹² The curcumin (turmeric) group also had fewer adverse effects.¹²

Cancer. There has been a great deal of research on turmeric’s anti-cancer properties, but clinical evidence is lacking. In vitro evidence, animal studies, and small clinical trials suggest that curcumin may help prevent or treat several types of cancers, but the overall evidence is poor. Nonetheless, curcumin and turmeric have been or are currently being evaluated for the treatment or prevention of prostate, liver, breast, skin, gynecologic, hematologic, pulmonary, thymic, bone, brain, and colon cancer.^13-18

Oral submucous fibrosis. A small randomized trial found improvement in oral function with curcumin lozenges, when compared to placebo, indicating that turmeric may hold promise as a treatment of oral submucous fibrosis.¹⁹

Uveitis. A small pilot study of 32 patients suggested that oral curcumin may be as effective as corticosteroids for uveitis.²⁰

Heart disease. Curcumin may have a cardiovascular protective role, as it has been shown to reduce atherosclerosis, but a reduction in myocardial infarction or stroke has not been documented.²¹

Alzheimer’s dementia. Animal studies have shown a reduction in amyloid plaque formation with curcumin.²²

Adverse effects (and precautions)

Turmeric in food is considered safe. A variety of animal and human studies have also indicated that curcumin is safe and well tolerated, even at very high doses.¹³ However, taking large amounts of turmeric for long periods of time could cause stomach upset and gastric ulcers. In addition, patients with gallstones or bile obstruction should use it with caution due to increased bile production.⁷

Because turmeric may lower blood sugar levels, patients with diabetes should monitor for hypoglycemia when using turmeric in combination with diabetic medications. Similarly, those with bleeding disorders taking blood thinners should use turmeric and curcumin with caution, because it can inhibit platelet aggregation.²³

Although it is safe to eat foods with turmeric during pregnancy, pregnant and breastfeeding women should not take turmeric supplements, as the safety of large doses in pregnancy is unknown.

The bottom line

Turmeric/curcumin has anti-inflammatory properties and may be useful as an adjunct for ulcerative colitis and to improve the symptoms of OA. It may also have anti-carcinogenic properties, although definitive data are lacking. Those with a history of gastrointestinal conditions such as gastric ulcer, patients taking blood thinners, and patients with diabetes who are prone to low blood sugar levels should use turmeric/curcumin with caution.

Overview

Chamomile, a member of the Asteraceae/Compositae family, is one of the oldest herbal medicines. It has been used for hay fever, inflammation, muscle spasms, menstrual disorders, insomnia, ulcers, wounds, gastrointestinal disorders, rheumatic pain, and hemorrhoids. Essential oils of chamomile are used extensively in cosmetics and aromatherapy. Many different preparations have been developed, the most popular being herbal tea.²⁴

A controlled clinical trial of chamomile extract suggested that it may have modest anxiolytic activity in patients with mild to moderate generalized anxiety disorder.

Individuals with a hypersensitivity to plants of the Asteraceae (Compositae) family such as ragweed (Ambrosia spp.), marigold flower (Calendula officinalis), and chrysanthemum (Chrysanthemum spp.) may show a similar reaction to chamomile.²⁵

Anxiety. A controlled clinical trial of chamomile extract for generalized anxiety disorder (GAD) suggested that it may have modest anxiolytic activity in patients with mild to moderate GAD.²⁶ Another randomized, double-blind, placebo-controlled trial found oral chamomile extract was efficacious and well-tolerated in patients experiencing mild to moderate GAD and may provide an alternative therapeutic anxiolytic for patients with mild GAD.²⁵ In addition to its anxiolytic activity, chamomile may also provide clinically meaningful antidepressant activity.²⁶

Insomnia. Chamomile may have some impact on sleep diary measures (total sleep time, sleep efficiency, sleep latency, wake after sleep onset, sleep quality, and number of awakenings) relative to placebo in adults with chronic primary insomnia, according to a small randomized, double-blind, placebo-controlled pilot trial involving 34 patients.²⁷ However, a systematic review found no statistically significant difference between any herbal medicine (including chamomile) and placebo, for clinical efficacy in patients with insomnia. A similar, or smaller, number of adverse events per person were reported with chamomile compared with placebo, suggesting safe use.²⁸

Infantile colic. A small prospective double-blind study on the use of chamomile-containing tea on infantile colic showed statistically significant symptom improvement in tea-treated infants. The study did note, however, that prolonged ingestion of herbal teas may lead to decreased milk intake.^29,30

Adverse effects

As noted earlier, a systematic review found that the number of adverse events per person reported with chamomile was comparable to the number associated with placebo, suggesting that it is safe.²⁸

The bottom line

Chamomile appears to be safe with minimal adverse effects and may be effective for the treatment of anxiety, insomnia, and infantile colic.

Rosemary

Overview

Rosemary, officially known as Rosmarinus officinalis, is a medicinal evergreen plant native to the Mediterranean area that appears to increase microcapillary perfusion.³¹

Topical rosemary oil may be useful in the treatment of alopecia, with minimal adverse effects.

Alopecia. A randomized double-blind controlled trial found that essential oils including rosemary oil (as well as thyme, lavender, and cedarwood) massaged into the scalp improved hair growth in almost half of patients with alopecia areata after 7 months.³² Another randomized trial comparing rosemary oil to minoxidil 2% for androgenetic alopecia showed a significant increase in hair count at the 6-month endpoint compared with the baseline, but no significant difference was found between the study groups regarding hair count either at Month 3 or Month 6 (P >.05). ³¹

Adverse effects

In the randomized trial described above comparing rosemary oil to minoxidil 2%, adverse effects appeared to be rare for topical rosemary oil. Scalp itching was more frequent in the minoxidil group.³¹

The bottom line

Topical rosemary oil may be useful in the treatment of alopecia with minimal adverse effects.

Overview

Coffee is one of the most widely used botanicals with approximately 3.5 billion cups of coffee consumed per day worldwide. It is a popular beverage because of its unique aromatic taste and its use as a central nervous system stimulant. The coffee tree (genus coffea) is found throughout Latin America, Africa, and eastern Asia. Two of the most common commercially grown species are Coffea arabica (Arabicas) and Coffea canephora (Robusta). Processing and roasting methods may differ and produce variations in flavor and aroma. The degree of roasting also affects the caffeine content.

Coffee consumption leads to increased alertness and can boost mental performance. Based on the literature and US Food and Drug Administration recommendations, four 8-oz cups of coffee (about 400 mg of caffeine) daily is an acceptable average amount of caffeine. More than 500 mg/d is considered excessive use of coffee.^33,34

Overall mortality. A 2008 study showed that regular coffee was not associated with increased or decreased mortality in both men and women.³⁵ However, more recent studies show an inverse relationship between mortality and coffee consumption.

Specifically, a 2014 meta-analysis found an inverse relationship between coffee and mortality.³⁶ A large prospective cohort study from 2015 that included 79,234 women and 76,704 men found that drinking coffee was inversely associated with overall mortality.³⁷ In this cohort study, an inverse association were observed for deaths from heart disease, respiratory disease, diabetes, and self-harm.³⁷ While mechanisms were not analyzed, coffee may reduce mortality risk by affecting inflammation, lung function, insulin sensitivity, and depression.

Cardiovascular disease. Coffee consumption may modestly reduce the risk of stroke, according to a prospective cohort study of 83,076 women from the Nurses’ Health Study who were followed for 24 years.³⁸ Reduced cardiovascular mortality was also found in a large prospective cohort study, as noted in the mortality discussion above.³⁷ A 2014 meta-analysis concluded that coffee consumption is inversely associated with cardiovascular mortality. Drinking 3 or 4 cups a day appears to be the amount that may decrease one’s risk of death when compared to those who do not drink coffee at all.³⁶

Liver disease. Friedrich et al performed a study involving 379 patients with end stage liver disease, and found that coffee consumption delayed the progression of disease in patients with both alcoholic liver disease and primary sclerosing cholangitis.³⁹ Coffee consumption also increased long-term survival after liver transplantation.³⁹ However, the study found that coffee did not have any effect on patients with chronic viral hepatitis.

In a 2016 meta-analysis, caffeinated coffee consumption reduced hepatic fibrosis of nonalcoholic fatty liver disease, although caffeine consumption did not reduce the prevalence of nonalcoholic fatty liver disease.⁴⁰ Another meta-analysis, including 16 studies, also found caffeine reduced the risk for hepatic fibrosis and cirrhosis.⁴¹

Depression. Based on 2 different systematic reviews and meta-analyses from 2016, coffee consumption appears to have a significant protective effect, decreasing the risk of developing depression.^40,42

Alzheimer’s disease/dementia. Coffee, tea, and caffeine consumption show promise in reducing the risk of cognitive decline and dementia. Individuals who consume one to 2 cups of coffee per day had a decreased incidence of mild cognitive impairment compared to non-drinkers.⁴³ A 2015 Japanese study also found an inverse association between coffee consumption and dementia among women, nonsmokers, and those who do not drink alcohol.⁴⁴ Most recently, a 2016 study, the Women’s Health Initiative Memory Study, looked at incident dementia rates in women >65 years of age with high vs low caffeine intake. Women with higher caffeine intake were less likely to develop dementia or any cognitive impairment compared with those consuming <64 mg/day.⁴⁵

Type 2 diabetes. A 2009 prospective cohort study, which included 40,011 participants followed for more than 10 years, found that drinking at least 3 cups of coffee or tea was associated with a lowered risk of type 2 diabetes.⁴⁶ A 2009 systematic review of 20 cohort studies showed that high intakes of coffee, decaffeinated coffee, and tea are associated with a reduced risk of diabetes.⁴⁷

A meta-analysis of 12 studies involving 832,956 participants found an inverse relationship between cutaneous melanoma and coffee consumption.

Melanoma. A meta-analysis of 12 studies involving 832,956 participants demon­strated an inverse relationship between cutaneous melanoma and coffee consumption.⁴⁷ The risk of melanoma decreased by 3% and 4% for one cup/day of total coffee and caffeinated coffee consumption, respectively. Furthermore, a 2016 meta-analysis found that caffeinated coffee may have greater chemopreventive effects against melanoma than decaffeinated coffee.⁴⁸

Adverse effects

Despite the many potential benefits of coffee, caffeine is a potent drug that should be used with caution.⁴⁹ People with underlying heart problems should avoid caffeine due to concern that it may cause palpitations from tachycardia. It may worsen anxiety problems or depression. Coffee may increase the production of stomach acids, which can worsen acid reflux or stomach ulcers.

Regular coffee intake is associated with a lower risk of mortality, reduced CV events, and a reduction in liver disease progression.

Caffeine is a potent diuretic and may decrease absorption of calcium and cause OA. Caffeine may cause dependence and withdrawal symptoms. Some of the symptoms of withdrawal include drowsiness, headaches, irritability, nausea, and vomiting. It may disrupt sleeping patterns by causing jitters and sleeplessness.⁴⁹ Additionally, large amounts of caffeine may cause overdose and death.

The bottom line

Regular coffee intake is associated with a lower risk of mortality, reduced cardiovascular events, and a reduction in liver disease progression. Coffee may also have some utility for improving cognitive function and reducing the risk of type 2 diabetes. Caffeinated coffee should be limited to no more than 32 oz per day, due to the risk of insomnia, palpitations, anxiety, and gastritis.

Overview

Few natural products have been claimed to successfully treat as many disorders as chocolate. The modern concept of chocolate as food has overshadowed its traditional medicinal use, although recent trials have looked at evidence for some of its traditional uses. Chocolate is processed from the pod of the cacao plant. The earliest evidence for its medical use is in Mayan civilizations, and for most of its approximately 4000-year history, chocolate was consumed as a bitter drink referred to as the “drink of the Gods.” The traditional drink was mixed with water, vanilla, honey, chili peppers, and other spices. Important components in chocolate include flavonoids (antioxidants), cocoa butter, caffeine, theobromine, and phenylethylamine.  

Chocolate has stimulating, anti-inflammatory, neuroprotective, and cardioprotective effects, and improves the bioavailability of nitric oxide, which can improve blood pressure and platelet function.⁵⁰ Epicatechin (an antioxidant) in cocoa is primarily responsible for its favorable impact on vascular endothelium via its effect on both acute and chronic upregulation of nitric oxide production. Other cardiovascular effects are mediated by the anti-inflammatory effects of cocoa polyphenols, and modulated through the activity of NF-kappaB.⁵¹

Multiple studies have shown that chocolate is associated with a reduction in cardiovascular risk.

Dark chocolate appears to have the greatest benefit, as milk binds to antioxidants in chocolate, making them unavailable. Therefore, milk chocolate is not a good antioxidant source. There is no specific amount of chocolate that is known to be ideal, but an average of one to 2 ounces per day is often used in studies.

Cardiovascular effects. Chocolate does contain saturated fat, but a comparative, double-blind study found that short-term use of cocoa powder lowered plasma low-density lipoprotein (LDL) cholesterol, oxidized LDL, and apo B concentrations, and the plasma high-density lipoprotein (HDL) cholesterol concentration increased, relative to baseline in the low-, middle-, and high-cocoa groups.⁵² A small randomized crossover trial without clinical outcomes indicated that chocolate may increase HDL cholesterol without increasing weight.⁵³

A meta-analysis of short-term (2-12 weeks) treatment with dark chocolate/cocoa products showed reductions in LDL and total cholesterol, but no changes in HDL or triglycerides.⁵⁴ Another meta-analysis of RCTs, however, showed no short-term effect of cocoa/chocolate on lipid concentrations.⁵⁵ A randomized, placebo-controlled double-blind study of 62 patients with diabetes and hypertension showed that high polyphenol chocolate improved triglyceride levels.⁵⁶

Chocolate intake was associated with a lower risk of cognitive decline, with the greatest benefit noted in those who averaged more than one chocolate bar per week.

Multiple studies have shown that chocolate is associated with a reduction in cardiovascular risk.^57-59 A best case scenario analysis using a Markov model to predict the long-term effectiveness and cost effectiveness of daily dark chocolate consumption in a population with metabolic syndrome at high risk of cardiovascular disease concluded that daily consumption of dark chocolate can reduce cardiovascular events by 85 per 10,000 population treated over 10 years. The study concluded that $42 could be cost effectively spent per person per year on prevention strategies using dark chocolate.⁵⁹

In addition, a meta-analysis of 7 observational studies showed that high levels of chocolate consumption (any type) were associated with a 29% reduction in stroke compared with the lowest levels of chocolate intake.⁵⁷ Results of a similar meta-analysis from Neurology in 2012 also suggested that moderate chocolate consumption (any type) may lower the risk of stroke.⁶⁰

That said, 2 systematic reviews specifically relating to the risk of coronary heart disease and chocolate intake were inconclusive.^61-62

Blood pressure (BP). An RCT published in JAMA indicates that inclusion of small amounts of polyphenol-rich dark chocolate as part of a usual diet efficiently reduced BP and improved the formation of vasodilative nitric oxide.⁶³ A meta-analysis of 10 RCTs also showed mean BP change in the active cocoa treatment arms across all trials was -4.5 mm Hg (95% confidence interval (CI), -5.9 to -3.2; P<.001) for systolic BP and -2.5 mm Hg (95% CI, -3.9 to -1.2; P<.001) for diastolic BP.⁶⁴

A Cochrane Review meta-analysis of 20 studies revealed a statistically significant BP-reducing effect of flavanol-rich cocoa products compared with control in short-term trials of 2 to 18 weeks' duration.⁶⁵ Because studies have shown improvement in BP with chocolate intake, investigations into a role of chocolate in the prevention of preeclampsia have been undertaken. In some studies, chocolate intake was associated with reduced odds of preeclampsia and gestational hypertension.^66,67

Diabetes. Chocolate may exert significant vascular protection because of its antioxidant properties and possible increase of nitric oxide bioavailability, which can influence glucose uptake. A small trial comparing the effects of either dark or white chocolate bars (which do not contain the polyphenols) showed improved BP and glucose and insulin responses to an oral glucose tolerance test in healthy subjects on dark chocolate, but not white chocolate.⁶⁸ A comparison of chocolate consumption and risk of diabetes in the Physicians’ Health Study showed an inverse relationship between chocolate intake with incident disease, but this association appeared only to apply in younger and normal-body weight men after controlling for comprehensive lifestyles, including total energy consumption.⁶⁹

Fatigue. The effect of chocolate on a person’s energy level has been noted for centuries.⁷⁰ A small randomized trial showed improved energy levels in those treated with higher chocolate intakes. In a double-blind, randomized, clinical pilot crossover study, high cocoa liquor/polyphenol rich chocolate, reduced fatigue in subjects with chronic fatigue syndrome.⁷¹

Anxiety. A small randomized trial showed chocolate decreased anxiety in high-anxiety trait subjects and improved the anxiety level and the energy levels of low-anxiety trait participants.⁷²

Eye effects. The literature presents conflicting evidence regarding the effect of flavonoids on patients with glaucoma and ocular hypertension. However, a meta-analysis showed that flavonoids have a promising role in improving visual function in patients with glaucoma and ocular hypertension, and appear to play a part in both improving and slowing the progression of visual field loss.⁷³

Cognitive decline. Chocolate intake (any type) was associated with a lower risk of cognitive decline (RR = 0.59; 95% CI, 0.38-0.92) with the greatest benefit noted in those who averaged more than one chocolate bar or one tablespoon of cocoa powder per week. This protective effect was observed only among subjects with an average daily consumption of caffeine <75  mg (69% of the participants; RR = 0.50; 95% CI, 0.31-0.82).⁷⁴

The bottom line

Chocolate with high cocoa content (dark chocolate) appears to be safe and beneficial as part of a healthy diet and lifestyle that includes exercise and stress reduction to decrease cardiovascular risk and may improve energy levels.

CORRESPONDENCE
Michael Malone, MD, Family and Community Medicine, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033; [email protected].

More than a third of American adults use complementary and alternative medicine.¹ Unfortunately, the public’s enthusiasm for herbal products is not always consistent with the scientific evidence supporting their use. In part one of this series, we discussed the studies that have been done on capsaicin, butterbur, green tea, and peppermint. In this installment, we outline the research on 5 additional remedies: turmeric/curcumin, which may be of benefit in ulcerative colitis; chamomile, which appears to offer relief to patients with anxiety; rosemary, which may help treat alopecia; as well as coffee and cocoa, which may have some cardiovascular benefits (TABLE).

Turmeric/curcumin

Overview

Turmeric (Curcuma longa), a relative of ginger, has been used for 4000 years to treat a variety of conditions.^2,3 Curcumin is the yellow pigment isolated from the rhizomes of Curcuma longa, commonly known as turmeric.³ Turmeric powder contains 5% curcumin, which is the main biologically active compound. Although it grows in many tropical locations, most turmeric is grown in India, where it is used as a main ingredient in curry. The roots and bulbs of turmeric that are used in medicine are generally boiled and dried, which results in a yellow powder.

Turmeric has been used in both Ayurvedic and Chinese medicine for its anti-inflammatory properties, in the treatment of digestive and liver problems, to fight infections, and to help heal skin diseases and wounds.^3-7

Functional GI disorders. A recent review noted that curcumin has been shown in several preclinical studies and uncontrolled clinical trials to have effects on gut inflammation, gut permeability, and the brain-gut axis, especially in functional GI disorders.⁷ A double-blind, placebo-controlled study from 1989 found that turmeric reduced symptoms of bloating and gas in subjects suffering from undifferentiated dyspepsia.⁸

Ulcerative colitis (UC). A 2012 Cochrane review noted that curcumin appears to be a safe and effective therapy for maintenance of remission in quiescent UC when given as adjunctive therapy along with mesalamine or sulfasalazine.⁹ In a 2015 randomized controlled trial (RCT), the addition of curcumin to mesalamine therapy was superior to the combination of placebo and mesalamine in inducing clinical and endoscopic remission in patients with mild-to-moderate active UC, producing no apparent adverse effects.¹⁰

Osteoarthritis (OA). Because of turmeric’s ability to reduce inflammation, it may help relieve OA pain.³ Clinical evidence is scant for the anti-arthritic efficacy of turmeric dietary supplements, although animal studies indicate that turmeric prevents inflammation through regulation of NF-kappaB-regulated genes that regulate the immune and inflammatory response.⁶ Inflammatory cell influx, joint levels of prostaglandin E2, and periarticular osteoclast formation were also inhibited by turmeric extract treatment.⁶

A 2013 review of turmeric for OA concluded that observational studies and in vitro results are promising for the use of curcumin for OA, but well-designed clinical studies were lacking and are needed to support the efficacy of curcumin in OA patients.¹¹ How­ever, in a 2014 randomized trial of 367 patients, turmeric appeared to be similar in efficacy to ibuprofen for the treatment of pain and disability in adults with knee OA.¹² The curcumin (turmeric) group also had fewer adverse effects.¹²

Cancer. There has been a great deal of research on turmeric’s anti-cancer properties, but clinical evidence is lacking. In vitro evidence, animal studies, and small clinical trials suggest that curcumin may help prevent or treat several types of cancers, but the overall evidence is poor. Nonetheless, curcumin and turmeric have been or are currently being evaluated for the treatment or prevention of prostate, liver, breast, skin, gynecologic, hematologic, pulmonary, thymic, bone, brain, and colon cancer.^13-18

Oral submucous fibrosis. A small randomized trial found improvement in oral function with curcumin lozenges, when compared to placebo, indicating that turmeric may hold promise as a treatment of oral submucous fibrosis.¹⁹

Uveitis. A small pilot study of 32 patients suggested that oral curcumin may be as effective as corticosteroids for uveitis.²⁰

Heart disease. Curcumin may have a cardiovascular protective role, as it has been shown to reduce atherosclerosis, but a reduction in myocardial infarction or stroke has not been documented.²¹

Alzheimer’s dementia. Animal studies have shown a reduction in amyloid plaque formation with curcumin.²²

Adverse effects (and precautions)

Turmeric in food is considered safe. A variety of animal and human studies have also indicated that curcumin is safe and well tolerated, even at very high doses.¹³ However, taking large amounts of turmeric for long periods of time could cause stomach upset and gastric ulcers. In addition, patients with gallstones or bile obstruction should use it with caution due to increased bile production.⁷

Because turmeric may lower blood sugar levels, patients with diabetes should monitor for hypoglycemia when using turmeric in combination with diabetic medications. Similarly, those with bleeding disorders taking blood thinners should use turmeric and curcumin with caution, because it can inhibit platelet aggregation.²³

Although it is safe to eat foods with turmeric during pregnancy, pregnant and breastfeeding women should not take turmeric supplements, as the safety of large doses in pregnancy is unknown.

The bottom line

Turmeric/curcumin has anti-inflammatory properties and may be useful as an adjunct for ulcerative colitis and to improve the symptoms of OA. It may also have anti-carcinogenic properties, although definitive data are lacking. Those with a history of gastrointestinal conditions such as gastric ulcer, patients taking blood thinners, and patients with diabetes who are prone to low blood sugar levels should use turmeric/curcumin with caution.

Overview

Chamomile, a member of the Asteraceae/Compositae family, is one of the oldest herbal medicines. It has been used for hay fever, inflammation, muscle spasms, menstrual disorders, insomnia, ulcers, wounds, gastrointestinal disorders, rheumatic pain, and hemorrhoids. Essential oils of chamomile are used extensively in cosmetics and aromatherapy. Many different preparations have been developed, the most popular being herbal tea.²⁴

A controlled clinical trial of chamomile extract suggested that it may have modest anxiolytic activity in patients with mild to moderate generalized anxiety disorder.

Individuals with a hypersensitivity to plants of the Asteraceae (Compositae) family such as ragweed (Ambrosia spp.), marigold flower (Calendula officinalis), and chrysanthemum (Chrysanthemum spp.) may show a similar reaction to chamomile.²⁵

Anxiety. A controlled clinical trial of chamomile extract for generalized anxiety disorder (GAD) suggested that it may have modest anxiolytic activity in patients with mild to moderate GAD.²⁶ Another randomized, double-blind, placebo-controlled trial found oral chamomile extract was efficacious and well-tolerated in patients experiencing mild to moderate GAD and may provide an alternative therapeutic anxiolytic for patients with mild GAD.²⁵ In addition to its anxiolytic activity, chamomile may also provide clinically meaningful antidepressant activity.²⁶

Insomnia. Chamomile may have some impact on sleep diary measures (total sleep time, sleep efficiency, sleep latency, wake after sleep onset, sleep quality, and number of awakenings) relative to placebo in adults with chronic primary insomnia, according to a small randomized, double-blind, placebo-controlled pilot trial involving 34 patients.²⁷ However, a systematic review found no statistically significant difference between any herbal medicine (including chamomile) and placebo, for clinical efficacy in patients with insomnia. A similar, or smaller, number of adverse events per person were reported with chamomile compared with placebo, suggesting safe use.²⁸

Infantile colic. A small prospective double-blind study on the use of chamomile-containing tea on infantile colic showed statistically significant symptom improvement in tea-treated infants. The study did note, however, that prolonged ingestion of herbal teas may lead to decreased milk intake.^29,30

Adverse effects

As noted earlier, a systematic review found that the number of adverse events per person reported with chamomile was comparable to the number associated with placebo, suggesting that it is safe.²⁸

The bottom line

Chamomile appears to be safe with minimal adverse effects and may be effective for the treatment of anxiety, insomnia, and infantile colic.

Rosemary

Overview

Rosemary, officially known as Rosmarinus officinalis, is a medicinal evergreen plant native to the Mediterranean area that appears to increase microcapillary perfusion.³¹

Topical rosemary oil may be useful in the treatment of alopecia, with minimal adverse effects.

Alopecia. A randomized double-blind controlled trial found that essential oils including rosemary oil (as well as thyme, lavender, and cedarwood) massaged into the scalp improved hair growth in almost half of patients with alopecia areata after 7 months.³² Another randomized trial comparing rosemary oil to minoxidil 2% for androgenetic alopecia showed a significant increase in hair count at the 6-month endpoint compared with the baseline, but no significant difference was found between the study groups regarding hair count either at Month 3 or Month 6 (P >.05). ³¹

Adverse effects

In the randomized trial described above comparing rosemary oil to minoxidil 2%, adverse effects appeared to be rare for topical rosemary oil. Scalp itching was more frequent in the minoxidil group.³¹

The bottom line

Topical rosemary oil may be useful in the treatment of alopecia with minimal adverse effects.

Overview

Coffee is one of the most widely used botanicals with approximately 3.5 billion cups of coffee consumed per day worldwide. It is a popular beverage because of its unique aromatic taste and its use as a central nervous system stimulant. The coffee tree (genus coffea) is found throughout Latin America, Africa, and eastern Asia. Two of the most common commercially grown species are Coffea arabica (Arabicas) and Coffea canephora (Robusta). Processing and roasting methods may differ and produce variations in flavor and aroma. The degree of roasting also affects the caffeine content.

Coffee consumption leads to increased alertness and can boost mental performance. Based on the literature and US Food and Drug Administration recommendations, four 8-oz cups of coffee (about 400 mg of caffeine) daily is an acceptable average amount of caffeine. More than 500 mg/d is considered excessive use of coffee.^33,34

Overall mortality. A 2008 study showed that regular coffee was not associated with increased or decreased mortality in both men and women.³⁵ However, more recent studies show an inverse relationship between mortality and coffee consumption.

Specifically, a 2014 meta-analysis found an inverse relationship between coffee and mortality.³⁶ A large prospective cohort study from 2015 that included 79,234 women and 76,704 men found that drinking coffee was inversely associated with overall mortality.³⁷ In this cohort study, an inverse association were observed for deaths from heart disease, respiratory disease, diabetes, and self-harm.³⁷ While mechanisms were not analyzed, coffee may reduce mortality risk by affecting inflammation, lung function, insulin sensitivity, and depression.

Cardiovascular disease. Coffee consumption may modestly reduce the risk of stroke, according to a prospective cohort study of 83,076 women from the Nurses’ Health Study who were followed for 24 years.³⁸ Reduced cardiovascular mortality was also found in a large prospective cohort study, as noted in the mortality discussion above.³⁷ A 2014 meta-analysis concluded that coffee consumption is inversely associated with cardiovascular mortality. Drinking 3 or 4 cups a day appears to be the amount that may decrease one’s risk of death when compared to those who do not drink coffee at all.³⁶

Liver disease. Friedrich et al performed a study involving 379 patients with end stage liver disease, and found that coffee consumption delayed the progression of disease in patients with both alcoholic liver disease and primary sclerosing cholangitis.³⁹ Coffee consumption also increased long-term survival after liver transplantation.³⁹ However, the study found that coffee did not have any effect on patients with chronic viral hepatitis.

In a 2016 meta-analysis, caffeinated coffee consumption reduced hepatic fibrosis of nonalcoholic fatty liver disease, although caffeine consumption did not reduce the prevalence of nonalcoholic fatty liver disease.⁴⁰ Another meta-analysis, including 16 studies, also found caffeine reduced the risk for hepatic fibrosis and cirrhosis.⁴¹

Depression. Based on 2 different systematic reviews and meta-analyses from 2016, coffee consumption appears to have a significant protective effect, decreasing the risk of developing depression.^40,42

Alzheimer’s disease/dementia. Coffee, tea, and caffeine consumption show promise in reducing the risk of cognitive decline and dementia. Individuals who consume one to 2 cups of coffee per day had a decreased incidence of mild cognitive impairment compared to non-drinkers.⁴³ A 2015 Japanese study also found an inverse association between coffee consumption and dementia among women, nonsmokers, and those who do not drink alcohol.⁴⁴ Most recently, a 2016 study, the Women’s Health Initiative Memory Study, looked at incident dementia rates in women >65 years of age with high vs low caffeine intake. Women with higher caffeine intake were less likely to develop dementia or any cognitive impairment compared with those consuming <64 mg/day.⁴⁵

Type 2 diabetes. A 2009 prospective cohort study, which included 40,011 participants followed for more than 10 years, found that drinking at least 3 cups of coffee or tea was associated with a lowered risk of type 2 diabetes.⁴⁶ A 2009 systematic review of 20 cohort studies showed that high intakes of coffee, decaffeinated coffee, and tea are associated with a reduced risk of diabetes.⁴⁷

A meta-analysis of 12 studies involving 832,956 participants found an inverse relationship between cutaneous melanoma and coffee consumption.

Melanoma. A meta-analysis of 12 studies involving 832,956 participants demon­strated an inverse relationship between cutaneous melanoma and coffee consumption.⁴⁷ The risk of melanoma decreased by 3% and 4% for one cup/day of total coffee and caffeinated coffee consumption, respectively. Furthermore, a 2016 meta-analysis found that caffeinated coffee may have greater chemopreventive effects against melanoma than decaffeinated coffee.⁴⁸

Adverse effects

Despite the many potential benefits of coffee, caffeine is a potent drug that should be used with caution.⁴⁹ People with underlying heart problems should avoid caffeine due to concern that it may cause palpitations from tachycardia. It may worsen anxiety problems or depression. Coffee may increase the production of stomach acids, which can worsen acid reflux or stomach ulcers.

Regular coffee intake is associated with a lower risk of mortality, reduced CV events, and a reduction in liver disease progression.

Caffeine is a potent diuretic and may decrease absorption of calcium and cause OA. Caffeine may cause dependence and withdrawal symptoms. Some of the symptoms of withdrawal include drowsiness, headaches, irritability, nausea, and vomiting. It may disrupt sleeping patterns by causing jitters and sleeplessness.⁴⁹ Additionally, large amounts of caffeine may cause overdose and death.

The bottom line

Regular coffee intake is associated with a lower risk of mortality, reduced cardiovascular events, and a reduction in liver disease progression. Coffee may also have some utility for improving cognitive function and reducing the risk of type 2 diabetes. Caffeinated coffee should be limited to no more than 32 oz per day, due to the risk of insomnia, palpitations, anxiety, and gastritis.

Overview

Few natural products have been claimed to successfully treat as many disorders as chocolate. The modern concept of chocolate as food has overshadowed its traditional medicinal use, although recent trials have looked at evidence for some of its traditional uses. Chocolate is processed from the pod of the cacao plant. The earliest evidence for its medical use is in Mayan civilizations, and for most of its approximately 4000-year history, chocolate was consumed as a bitter drink referred to as the “drink of the Gods.” The traditional drink was mixed with water, vanilla, honey, chili peppers, and other spices. Important components in chocolate include flavonoids (antioxidants), cocoa butter, caffeine, theobromine, and phenylethylamine.  

Chocolate has stimulating, anti-inflammatory, neuroprotective, and cardioprotective effects, and improves the bioavailability of nitric oxide, which can improve blood pressure and platelet function.⁵⁰ Epicatechin (an antioxidant) in cocoa is primarily responsible for its favorable impact on vascular endothelium via its effect on both acute and chronic upregulation of nitric oxide production. Other cardiovascular effects are mediated by the anti-inflammatory effects of cocoa polyphenols, and modulated through the activity of NF-kappaB.⁵¹

Multiple studies have shown that chocolate is associated with a reduction in cardiovascular risk.

Dark chocolate appears to have the greatest benefit, as milk binds to antioxidants in chocolate, making them unavailable. Therefore, milk chocolate is not a good antioxidant source. There is no specific amount of chocolate that is known to be ideal, but an average of one to 2 ounces per day is often used in studies.

Cardiovascular effects. Chocolate does contain saturated fat, but a comparative, double-blind study found that short-term use of cocoa powder lowered plasma low-density lipoprotein (LDL) cholesterol, oxidized LDL, and apo B concentrations, and the plasma high-density lipoprotein (HDL) cholesterol concentration increased, relative to baseline in the low-, middle-, and high-cocoa groups.⁵² A small randomized crossover trial without clinical outcomes indicated that chocolate may increase HDL cholesterol without increasing weight.⁵³

A meta-analysis of short-term (2-12 weeks) treatment with dark chocolate/cocoa products showed reductions in LDL and total cholesterol, but no changes in HDL or triglycerides.⁵⁴ Another meta-analysis of RCTs, however, showed no short-term effect of cocoa/chocolate on lipid concentrations.⁵⁵ A randomized, placebo-controlled double-blind study of 62 patients with diabetes and hypertension showed that high polyphenol chocolate improved triglyceride levels.⁵⁶

Chocolate intake was associated with a lower risk of cognitive decline, with the greatest benefit noted in those who averaged more than one chocolate bar per week.

Multiple studies have shown that chocolate is associated with a reduction in cardiovascular risk.^57-59 A best case scenario analysis using a Markov model to predict the long-term effectiveness and cost effectiveness of daily dark chocolate consumption in a population with metabolic syndrome at high risk of cardiovascular disease concluded that daily consumption of dark chocolate can reduce cardiovascular events by 85 per 10,000 population treated over 10 years. The study concluded that $42 could be cost effectively spent per person per year on prevention strategies using dark chocolate.⁵⁹

In addition, a meta-analysis of 7 observational studies showed that high levels of chocolate consumption (any type) were associated with a 29% reduction in stroke compared with the lowest levels of chocolate intake.⁵⁷ Results of a similar meta-analysis from Neurology in 2012 also suggested that moderate chocolate consumption (any type) may lower the risk of stroke.⁶⁰

That said, 2 systematic reviews specifically relating to the risk of coronary heart disease and chocolate intake were inconclusive.^61-62

Blood pressure (BP). An RCT published in JAMA indicates that inclusion of small amounts of polyphenol-rich dark chocolate as part of a usual diet efficiently reduced BP and improved the formation of vasodilative nitric oxide.⁶³ A meta-analysis of 10 RCTs also showed mean BP change in the active cocoa treatment arms across all trials was -4.5 mm Hg (95% confidence interval (CI), -5.9 to -3.2; P<.001) for systolic BP and -2.5 mm Hg (95% CI, -3.9 to -1.2; P<.001) for diastolic BP.⁶⁴

A Cochrane Review meta-analysis of 20 studies revealed a statistically significant BP-reducing effect of flavanol-rich cocoa products compared with control in short-term trials of 2 to 18 weeks' duration.⁶⁵ Because studies have shown improvement in BP with chocolate intake, investigations into a role of chocolate in the prevention of preeclampsia have been undertaken. In some studies, chocolate intake was associated with reduced odds of preeclampsia and gestational hypertension.^66,67

Diabetes. Chocolate may exert significant vascular protection because of its antioxidant properties and possible increase of nitric oxide bioavailability, which can influence glucose uptake. A small trial comparing the effects of either dark or white chocolate bars (which do not contain the polyphenols) showed improved BP and glucose and insulin responses to an oral glucose tolerance test in healthy subjects on dark chocolate, but not white chocolate.⁶⁸ A comparison of chocolate consumption and risk of diabetes in the Physicians’ Health Study showed an inverse relationship between chocolate intake with incident disease, but this association appeared only to apply in younger and normal-body weight men after controlling for comprehensive lifestyles, including total energy consumption.⁶⁹

Fatigue. The effect of chocolate on a person’s energy level has been noted for centuries.⁷⁰ A small randomized trial showed improved energy levels in those treated with higher chocolate intakes. In a double-blind, randomized, clinical pilot crossover study, high cocoa liquor/polyphenol rich chocolate, reduced fatigue in subjects with chronic fatigue syndrome.⁷¹

Anxiety. A small randomized trial showed chocolate decreased anxiety in high-anxiety trait subjects and improved the anxiety level and the energy levels of low-anxiety trait participants.⁷²

Eye effects. The literature presents conflicting evidence regarding the effect of flavonoids on patients with glaucoma and ocular hypertension. However, a meta-analysis showed that flavonoids have a promising role in improving visual function in patients with glaucoma and ocular hypertension, and appear to play a part in both improving and slowing the progression of visual field loss.⁷³

Cognitive decline. Chocolate intake (any type) was associated with a lower risk of cognitive decline (RR = 0.59; 95% CI, 0.38-0.92) with the greatest benefit noted in those who averaged more than one chocolate bar or one tablespoon of cocoa powder per week. This protective effect was observed only among subjects with an average daily consumption of caffeine <75  mg (69% of the participants; RR = 0.50; 95% CI, 0.31-0.82).⁷⁴

The bottom line

Chocolate with high cocoa content (dark chocolate) appears to be safe and beneficial as part of a healthy diet and lifestyle that includes exercise and stress reduction to decrease cardiovascular risk and may improve energy levels.

CORRESPONDENCE
Michael Malone, MD, Family and Community Medicine, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033; [email protected].

More than a third of American adults use complementary and alternative medicine.¹ Unfortunately, the public’s enthusiasm for herbal products is not always consistent with the scientific evidence supporting their use. In part one of this series, we discussed the studies that have been done on capsaicin, butterbur, green tea, and peppermint. In this installment, we outline the research on 5 additional remedies: turmeric/curcumin, which may be of benefit in ulcerative colitis; chamomile, which appears to offer relief to patients with anxiety; rosemary, which may help treat alopecia; as well as coffee and cocoa, which may have some cardiovascular benefits (TABLE).

Turmeric/curcumin

Overview

Turmeric (Curcuma longa), a relative of ginger, has been used for 4000 years to treat a variety of conditions.^2,3 Curcumin is the yellow pigment isolated from the rhizomes of Curcuma longa, commonly known as turmeric.³ Turmeric powder contains 5% curcumin, which is the main biologically active compound. Although it grows in many tropical locations, most turmeric is grown in India, where it is used as a main ingredient in curry. The roots and bulbs of turmeric that are used in medicine are generally boiled and dried, which results in a yellow powder.

Turmeric has been used in both Ayurvedic and Chinese medicine for its anti-inflammatory properties, in the treatment of digestive and liver problems, to fight infections, and to help heal skin diseases and wounds.^3-7

Functional GI disorders. A recent review noted that curcumin has been shown in several preclinical studies and uncontrolled clinical trials to have effects on gut inflammation, gut permeability, and the brain-gut axis, especially in functional GI disorders.⁷ A double-blind, placebo-controlled study from 1989 found that turmeric reduced symptoms of bloating and gas in subjects suffering from undifferentiated dyspepsia.⁸

Ulcerative colitis (UC). A 2012 Cochrane review noted that curcumin appears to be a safe and effective therapy for maintenance of remission in quiescent UC when given as adjunctive therapy along with mesalamine or sulfasalazine.⁹ In a 2015 randomized controlled trial (RCT), the addition of curcumin to mesalamine therapy was superior to the combination of placebo and mesalamine in inducing clinical and endoscopic remission in patients with mild-to-moderate active UC, producing no apparent adverse effects.¹⁰

Osteoarthritis (OA). Because of turmeric’s ability to reduce inflammation, it may help relieve OA pain.³ Clinical evidence is scant for the anti-arthritic efficacy of turmeric dietary supplements, although animal studies indicate that turmeric prevents inflammation through regulation of NF-kappaB-regulated genes that regulate the immune and inflammatory response.⁶ Inflammatory cell influx, joint levels of prostaglandin E2, and periarticular osteoclast formation were also inhibited by turmeric extract treatment.⁶

A 2013 review of turmeric for OA concluded that observational studies and in vitro results are promising for the use of curcumin for OA, but well-designed clinical studies were lacking and are needed to support the efficacy of curcumin in OA patients.¹¹ How­ever, in a 2014 randomized trial of 367 patients, turmeric appeared to be similar in efficacy to ibuprofen for the treatment of pain and disability in adults with knee OA.¹² The curcumin (turmeric) group also had fewer adverse effects.¹²

Cancer. There has been a great deal of research on turmeric’s anti-cancer properties, but clinical evidence is lacking. In vitro evidence, animal studies, and small clinical trials suggest that curcumin may help prevent or treat several types of cancers, but the overall evidence is poor. Nonetheless, curcumin and turmeric have been or are currently being evaluated for the treatment or prevention of prostate, liver, breast, skin, gynecologic, hematologic, pulmonary, thymic, bone, brain, and colon cancer.^13-18

Oral submucous fibrosis. A small randomized trial found improvement in oral function with curcumin lozenges, when compared to placebo, indicating that turmeric may hold promise as a treatment of oral submucous fibrosis.¹⁹

Uveitis. A small pilot study of 32 patients suggested that oral curcumin may be as effective as corticosteroids for uveitis.²⁰

Heart disease. Curcumin may have a cardiovascular protective role, as it has been shown to reduce atherosclerosis, but a reduction in myocardial infarction or stroke has not been documented.²¹

Alzheimer’s dementia. Animal studies have shown a reduction in amyloid plaque formation with curcumin.²²

Adverse effects (and precautions)

Turmeric in food is considered safe. A variety of animal and human studies have also indicated that curcumin is safe and well tolerated, even at very high doses.¹³ However, taking large amounts of turmeric for long periods of time could cause stomach upset and gastric ulcers. In addition, patients with gallstones or bile obstruction should use it with caution due to increased bile production.⁷

Because turmeric may lower blood sugar levels, patients with diabetes should monitor for hypoglycemia when using turmeric in combination with diabetic medications. Similarly, those with bleeding disorders taking blood thinners should use turmeric and curcumin with caution, because it can inhibit platelet aggregation.²³

Although it is safe to eat foods with turmeric during pregnancy, pregnant and breastfeeding women should not take turmeric supplements, as the safety of large doses in pregnancy is unknown.

The bottom line

Turmeric/curcumin has anti-inflammatory properties and may be useful as an adjunct for ulcerative colitis and to improve the symptoms of OA. It may also have anti-carcinogenic properties, although definitive data are lacking. Those with a history of gastrointestinal conditions such as gastric ulcer, patients taking blood thinners, and patients with diabetes who are prone to low blood sugar levels should use turmeric/curcumin with caution.

Overview

Chamomile, a member of the Asteraceae/Compositae family, is one of the oldest herbal medicines. It has been used for hay fever, inflammation, muscle spasms, menstrual disorders, insomnia, ulcers, wounds, gastrointestinal disorders, rheumatic pain, and hemorrhoids. Essential oils of chamomile are used extensively in cosmetics and aromatherapy. Many different preparations have been developed, the most popular being herbal tea.²⁴

A controlled clinical trial of chamomile extract suggested that it may have modest anxiolytic activity in patients with mild to moderate generalized anxiety disorder.

Individuals with a hypersensitivity to plants of the Asteraceae (Compositae) family such as ragweed (Ambrosia spp.), marigold flower (Calendula officinalis), and chrysanthemum (Chrysanthemum spp.) may show a similar reaction to chamomile.²⁵

Anxiety. A controlled clinical trial of chamomile extract for generalized anxiety disorder (GAD) suggested that it may have modest anxiolytic activity in patients with mild to moderate GAD.²⁶ Another randomized, double-blind, placebo-controlled trial found oral chamomile extract was efficacious and well-tolerated in patients experiencing mild to moderate GAD and may provide an alternative therapeutic anxiolytic for patients with mild GAD.²⁵ In addition to its anxiolytic activity, chamomile may also provide clinically meaningful antidepressant activity.²⁶

Insomnia. Chamomile may have some impact on sleep diary measures (total sleep time, sleep efficiency, sleep latency, wake after sleep onset, sleep quality, and number of awakenings) relative to placebo in adults with chronic primary insomnia, according to a small randomized, double-blind, placebo-controlled pilot trial involving 34 patients.²⁷ However, a systematic review found no statistically significant difference between any herbal medicine (including chamomile) and placebo, for clinical efficacy in patients with insomnia. A similar, or smaller, number of adverse events per person were reported with chamomile compared with placebo, suggesting safe use.²⁸

Infantile colic. A small prospective double-blind study on the use of chamomile-containing tea on infantile colic showed statistically significant symptom improvement in tea-treated infants. The study did note, however, that prolonged ingestion of herbal teas may lead to decreased milk intake.^29,30

Adverse effects

As noted earlier, a systematic review found that the number of adverse events per person reported with chamomile was comparable to the number associated with placebo, suggesting that it is safe.²⁸

The bottom line

Chamomile appears to be safe with minimal adverse effects and may be effective for the treatment of anxiety, insomnia, and infantile colic.

Rosemary

Overview

Rosemary, officially known as Rosmarinus officinalis, is a medicinal evergreen plant native to the Mediterranean area that appears to increase microcapillary perfusion.³¹

Topical rosemary oil may be useful in the treatment of alopecia, with minimal adverse effects.

Alopecia. A randomized double-blind controlled trial found that essential oils including rosemary oil (as well as thyme, lavender, and cedarwood) massaged into the scalp improved hair growth in almost half of patients with alopecia areata after 7 months.³² Another randomized trial comparing rosemary oil to minoxidil 2% for androgenetic alopecia showed a significant increase in hair count at the 6-month endpoint compared with the baseline, but no significant difference was found between the study groups regarding hair count either at Month 3 or Month 6 (P >.05). ³¹

Adverse effects

In the randomized trial described above comparing rosemary oil to minoxidil 2%, adverse effects appeared to be rare for topical rosemary oil. Scalp itching was more frequent in the minoxidil group.³¹

The bottom line

Topical rosemary oil may be useful in the treatment of alopecia with minimal adverse effects.

Overview

Coffee is one of the most widely used botanicals with approximately 3.5 billion cups of coffee consumed per day worldwide. It is a popular beverage because of its unique aromatic taste and its use as a central nervous system stimulant. The coffee tree (genus coffea) is found throughout Latin America, Africa, and eastern Asia. Two of the most common commercially grown species are Coffea arabica (Arabicas) and Coffea canephora (Robusta). Processing and roasting methods may differ and produce variations in flavor and aroma. The degree of roasting also affects the caffeine content.

Coffee consumption leads to increased alertness and can boost mental performance. Based on the literature and US Food and Drug Administration recommendations, four 8-oz cups of coffee (about 400 mg of caffeine) daily is an acceptable average amount of caffeine. More than 500 mg/d is considered excessive use of coffee.^33,34

Overall mortality. A 2008 study showed that regular coffee was not associated with increased or decreased mortality in both men and women.³⁵ However, more recent studies show an inverse relationship between mortality and coffee consumption.

Specifically, a 2014 meta-analysis found an inverse relationship between coffee and mortality.³⁶ A large prospective cohort study from 2015 that included 79,234 women and 76,704 men found that drinking coffee was inversely associated with overall mortality.³⁷ In this cohort study, an inverse association were observed for deaths from heart disease, respiratory disease, diabetes, and self-harm.³⁷ While mechanisms were not analyzed, coffee may reduce mortality risk by affecting inflammation, lung function, insulin sensitivity, and depression.

Cardiovascular disease. Coffee consumption may modestly reduce the risk of stroke, according to a prospective cohort study of 83,076 women from the Nurses’ Health Study who were followed for 24 years.³⁸ Reduced cardiovascular mortality was also found in a large prospective cohort study, as noted in the mortality discussion above.³⁷ A 2014 meta-analysis concluded that coffee consumption is inversely associated with cardiovascular mortality. Drinking 3 or 4 cups a day appears to be the amount that may decrease one’s risk of death when compared to those who do not drink coffee at all.³⁶

Liver disease. Friedrich et al performed a study involving 379 patients with end stage liver disease, and found that coffee consumption delayed the progression of disease in patients with both alcoholic liver disease and primary sclerosing cholangitis.³⁹ Coffee consumption also increased long-term survival after liver transplantation.³⁹ However, the study found that coffee did not have any effect on patients with chronic viral hepatitis.

In a 2016 meta-analysis, caffeinated coffee consumption reduced hepatic fibrosis of nonalcoholic fatty liver disease, although caffeine consumption did not reduce the prevalence of nonalcoholic fatty liver disease.⁴⁰ Another meta-analysis, including 16 studies, also found caffeine reduced the risk for hepatic fibrosis and cirrhosis.⁴¹

Depression. Based on 2 different systematic reviews and meta-analyses from 2016, coffee consumption appears to have a significant protective effect, decreasing the risk of developing depression.^40,42

Alzheimer’s disease/dementia. Coffee, tea, and caffeine consumption show promise in reducing the risk of cognitive decline and dementia. Individuals who consume one to 2 cups of coffee per day had a decreased incidence of mild cognitive impairment compared to non-drinkers.⁴³ A 2015 Japanese study also found an inverse association between coffee consumption and dementia among women, nonsmokers, and those who do not drink alcohol.⁴⁴ Most recently, a 2016 study, the Women’s Health Initiative Memory Study, looked at incident dementia rates in women >65 years of age with high vs low caffeine intake. Women with higher caffeine intake were less likely to develop dementia or any cognitive impairment compared with those consuming <64 mg/day.⁴⁵

Type 2 diabetes. A 2009 prospective cohort study, which included 40,011 participants followed for more than 10 years, found that drinking at least 3 cups of coffee or tea was associated with a lowered risk of type 2 diabetes.⁴⁶ A 2009 systematic review of 20 cohort studies showed that high intakes of coffee, decaffeinated coffee, and tea are associated with a reduced risk of diabetes.⁴⁷

A meta-analysis of 12 studies involving 832,956 participants found an inverse relationship between cutaneous melanoma and coffee consumption.

Melanoma. A meta-analysis of 12 studies involving 832,956 participants demon­strated an inverse relationship between cutaneous melanoma and coffee consumption.⁴⁷ The risk of melanoma decreased by 3% and 4% for one cup/day of total coffee and caffeinated coffee consumption, respectively. Furthermore, a 2016 meta-analysis found that caffeinated coffee may have greater chemopreventive effects against melanoma than decaffeinated coffee.⁴⁸

Adverse effects

Despite the many potential benefits of coffee, caffeine is a potent drug that should be used with caution.⁴⁹ People with underlying heart problems should avoid caffeine due to concern that it may cause palpitations from tachycardia. It may worsen anxiety problems or depression. Coffee may increase the production of stomach acids, which can worsen acid reflux or stomach ulcers.

Regular coffee intake is associated with a lower risk of mortality, reduced CV events, and a reduction in liver disease progression.

Caffeine is a potent diuretic and may decrease absorption of calcium and cause OA. Caffeine may cause dependence and withdrawal symptoms. Some of the symptoms of withdrawal include drowsiness, headaches, irritability, nausea, and vomiting. It may disrupt sleeping patterns by causing jitters and sleeplessness.⁴⁹ Additionally, large amounts of caffeine may cause overdose and death.

The bottom line

Regular coffee intake is associated with a lower risk of mortality, reduced cardiovascular events, and a reduction in liver disease progression. Coffee may also have some utility for improving cognitive function and reducing the risk of type 2 diabetes. Caffeinated coffee should be limited to no more than 32 oz per day, due to the risk of insomnia, palpitations, anxiety, and gastritis.

Overview

Few natural products have been claimed to successfully treat as many disorders as chocolate. The modern concept of chocolate as food has overshadowed its traditional medicinal use, although recent trials have looked at evidence for some of its traditional uses. Chocolate is processed from the pod of the cacao plant. The earliest evidence for its medical use is in Mayan civilizations, and for most of its approximately 4000-year history, chocolate was consumed as a bitter drink referred to as the “drink of the Gods.” The traditional drink was mixed with water, vanilla, honey, chili peppers, and other spices. Important components in chocolate include flavonoids (antioxidants), cocoa butter, caffeine, theobromine, and phenylethylamine.  

Chocolate has stimulating, anti-inflammatory, neuroprotective, and cardioprotective effects, and improves the bioavailability of nitric oxide, which can improve blood pressure and platelet function.⁵⁰ Epicatechin (an antioxidant) in cocoa is primarily responsible for its favorable impact on vascular endothelium via its effect on both acute and chronic upregulation of nitric oxide production. Other cardiovascular effects are mediated by the anti-inflammatory effects of cocoa polyphenols, and modulated through the activity of NF-kappaB.⁵¹

Multiple studies have shown that chocolate is associated with a reduction in cardiovascular risk.

Dark chocolate appears to have the greatest benefit, as milk binds to antioxidants in chocolate, making them unavailable. Therefore, milk chocolate is not a good antioxidant source. There is no specific amount of chocolate that is known to be ideal, but an average of one to 2 ounces per day is often used in studies.

Cardiovascular effects. Chocolate does contain saturated fat, but a comparative, double-blind study found that short-term use of cocoa powder lowered plasma low-density lipoprotein (LDL) cholesterol, oxidized LDL, and apo B concentrations, and the plasma high-density lipoprotein (HDL) cholesterol concentration increased, relative to baseline in the low-, middle-, and high-cocoa groups.⁵² A small randomized crossover trial without clinical outcomes indicated that chocolate may increase HDL cholesterol without increasing weight.⁵³

A meta-analysis of short-term (2-12 weeks) treatment with dark chocolate/cocoa products showed reductions in LDL and total cholesterol, but no changes in HDL or triglycerides.⁵⁴ Another meta-analysis of RCTs, however, showed no short-term effect of cocoa/chocolate on lipid concentrations.⁵⁵ A randomized, placebo-controlled double-blind study of 62 patients with diabetes and hypertension showed that high polyphenol chocolate improved triglyceride levels.⁵⁶

Chocolate intake was associated with a lower risk of cognitive decline, with the greatest benefit noted in those who averaged more than one chocolate bar per week.

Multiple studies have shown that chocolate is associated with a reduction in cardiovascular risk.^57-59 A best case scenario analysis using a Markov model to predict the long-term effectiveness and cost effectiveness of daily dark chocolate consumption in a population with metabolic syndrome at high risk of cardiovascular disease concluded that daily consumption of dark chocolate can reduce cardiovascular events by 85 per 10,000 population treated over 10 years. The study concluded that $42 could be cost effectively spent per person per year on prevention strategies using dark chocolate.⁵⁹

In addition, a meta-analysis of 7 observational studies showed that high levels of chocolate consumption (any type) were associated with a 29% reduction in stroke compared with the lowest levels of chocolate intake.⁵⁷ Results of a similar meta-analysis from Neurology in 2012 also suggested that moderate chocolate consumption (any type) may lower the risk of stroke.⁶⁰

That said, 2 systematic reviews specifically relating to the risk of coronary heart disease and chocolate intake were inconclusive.^61-62

Blood pressure (BP). An RCT published in JAMA indicates that inclusion of small amounts of polyphenol-rich dark chocolate as part of a usual diet efficiently reduced BP and improved the formation of vasodilative nitric oxide.⁶³ A meta-analysis of 10 RCTs also showed mean BP change in the active cocoa treatment arms across all trials was -4.5 mm Hg (95% confidence interval (CI), -5.9 to -3.2; P<.001) for systolic BP and -2.5 mm Hg (95% CI, -3.9 to -1.2; P<.001) for diastolic BP.⁶⁴

A Cochrane Review meta-analysis of 20 studies revealed a statistically significant BP-reducing effect of flavanol-rich cocoa products compared with control in short-term trials of 2 to 18 weeks' duration.⁶⁵ Because studies have shown improvement in BP with chocolate intake, investigations into a role of chocolate in the prevention of preeclampsia have been undertaken. In some studies, chocolate intake was associated with reduced odds of preeclampsia and gestational hypertension.^66,67

Diabetes. Chocolate may exert significant vascular protection because of its antioxidant properties and possible increase of nitric oxide bioavailability, which can influence glucose uptake. A small trial comparing the effects of either dark or white chocolate bars (which do not contain the polyphenols) showed improved BP and glucose and insulin responses to an oral glucose tolerance test in healthy subjects on dark chocolate, but not white chocolate.⁶⁸ A comparison of chocolate consumption and risk of diabetes in the Physicians’ Health Study showed an inverse relationship between chocolate intake with incident disease, but this association appeared only to apply in younger and normal-body weight men after controlling for comprehensive lifestyles, including total energy consumption.⁶⁹

Fatigue. The effect of chocolate on a person’s energy level has been noted for centuries.⁷⁰ A small randomized trial showed improved energy levels in those treated with higher chocolate intakes. In a double-blind, randomized, clinical pilot crossover study, high cocoa liquor/polyphenol rich chocolate, reduced fatigue in subjects with chronic fatigue syndrome.⁷¹

Anxiety. A small randomized trial showed chocolate decreased anxiety in high-anxiety trait subjects and improved the anxiety level and the energy levels of low-anxiety trait participants.⁷²

Eye effects. The literature presents conflicting evidence regarding the effect of flavonoids on patients with glaucoma and ocular hypertension. However, a meta-analysis showed that flavonoids have a promising role in improving visual function in patients with glaucoma and ocular hypertension, and appear to play a part in both improving and slowing the progression of visual field loss.⁷³

Cognitive decline. Chocolate intake (any type) was associated with a lower risk of cognitive decline (RR = 0.59; 95% CI, 0.38-0.92) with the greatest benefit noted in those who averaged more than one chocolate bar or one tablespoon of cocoa powder per week. This protective effect was observed only among subjects with an average daily consumption of caffeine <75  mg (69% of the participants; RR = 0.50; 95% CI, 0.31-0.82).⁷⁴

The bottom line

Chocolate with high cocoa content (dark chocolate) appears to be safe and beneficial as part of a healthy diet and lifestyle that includes exercise and stress reduction to decrease cardiovascular risk and may improve energy levels.

CORRESPONDENCE
Michael Malone, MD, Family and Community Medicine, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033; [email protected].

Over the past decade, bipolar disorder (BD) has gained widespread recognition in mainstream culture and in the media,¹ and awareness of this condition has increased substantially. As a result, patients commonly present with preconceived ideas about bipolarity that may or may not actually correspond with this diagnosis. In anticipation of seeing such patients, I offer 4 recommendations to help clinicians more accurately diagnose BD.

1. Screen for periods of manic or hypomanic mood. Effective screening questions include:

• “Have you ever had periods when you felt too happy, too angry, or on top of the world for several days in a row?”
• “Have you had periods when you would go several days without much sleep and still feel fine during the day?”

If the patient reports irritability rather than euphoria, try to better understand the phenomenology of his or her irritable mood. Among patients who experience mania, irritability often results from impatience, which in turn seems to be secondary to grandiosity, increased energy, and accelerated thought processes.²

2. Avoid using terms with low specificity, such as “mood swings” and “racing thoughts,” when you screen for manic symptoms. If the patient mentions these phrases, do not take them at face value; ask him or her to characterize them in detail. Differentiate chronic, quick fluctuations in affect—which are usually triggered by environmental factors and typically are reported by patients with personality disorders—from more persistent periods of mood polarization. Similarly, anxious patients commonly report having “racing thoughts.”

3. Distinguish patients who have a chronic, ongoing preoccupation with shopping from those who exhibit intermittent periods of excessive shopping and prodigality, which usually are associated with other manic symptoms.³ Spending money in excess is often cited as a classic symptom of mania or hypomania, but it may be an indicator of other conditions, such as compulsive buying.

4. Ask about any increases in goal-directed activity. This is a good way to identify true manic or hypomanic periods. Patients with anxiety or agitated depression may report an increase in psychomotor activity, but this is usually characterized more by restlessness and wandering, and not by a true increase in activity.

Consider a temporary diagnosis

When in doubt, it may be advisable to establish a temporary diagnosis of unspecified mood disorder, until you can learn more about the patient, obtain collateral information from family or friends, and request past medical records.

Over the past decade, bipolar disorder (BD) has gained widespread recognition in mainstream culture and in the media,¹ and awareness of this condition has increased substantially. As a result, patients commonly present with preconceived ideas about bipolarity that may or may not actually correspond with this diagnosis. In anticipation of seeing such patients, I offer 4 recommendations to help clinicians more accurately diagnose BD.

1. Screen for periods of manic or hypomanic mood. Effective screening questions include:

• “Have you ever had periods when you felt too happy, too angry, or on top of the world for several days in a row?”
• “Have you had periods when you would go several days without much sleep and still feel fine during the day?”

If the patient reports irritability rather than euphoria, try to better understand the phenomenology of his or her irritable mood. Among patients who experience mania, irritability often results from impatience, which in turn seems to be secondary to grandiosity, increased energy, and accelerated thought processes.²

2. Avoid using terms with low specificity, such as “mood swings” and “racing thoughts,” when you screen for manic symptoms. If the patient mentions these phrases, do not take them at face value; ask him or her to characterize them in detail. Differentiate chronic, quick fluctuations in affect—which are usually triggered by environmental factors and typically are reported by patients with personality disorders—from more persistent periods of mood polarization. Similarly, anxious patients commonly report having “racing thoughts.”

3. Distinguish patients who have a chronic, ongoing preoccupation with shopping from those who exhibit intermittent periods of excessive shopping and prodigality, which usually are associated with other manic symptoms.³ Spending money in excess is often cited as a classic symptom of mania or hypomania, but it may be an indicator of other conditions, such as compulsive buying.

4. Ask about any increases in goal-directed activity. This is a good way to identify true manic or hypomanic periods. Patients with anxiety or agitated depression may report an increase in psychomotor activity, but this is usually characterized more by restlessness and wandering, and not by a true increase in activity.

Consider a temporary diagnosis

When in doubt, it may be advisable to establish a temporary diagnosis of unspecified mood disorder, until you can learn more about the patient, obtain collateral information from family or friends, and request past medical records.

Over the past decade, bipolar disorder (BD) has gained widespread recognition in mainstream culture and in the media,¹ and awareness of this condition has increased substantially. As a result, patients commonly present with preconceived ideas about bipolarity that may or may not actually correspond with this diagnosis. In anticipation of seeing such patients, I offer 4 recommendations to help clinicians more accurately diagnose BD.

1. Screen for periods of manic or hypomanic mood. Effective screening questions include:

• “Have you ever had periods when you felt too happy, too angry, or on top of the world for several days in a row?”
• “Have you had periods when you would go several days without much sleep and still feel fine during the day?”

If the patient reports irritability rather than euphoria, try to better understand the phenomenology of his or her irritable mood. Among patients who experience mania, irritability often results from impatience, which in turn seems to be secondary to grandiosity, increased energy, and accelerated thought processes.²

2. Avoid using terms with low specificity, such as “mood swings” and “racing thoughts,” when you screen for manic symptoms. If the patient mentions these phrases, do not take them at face value; ask him or her to characterize them in detail. Differentiate chronic, quick fluctuations in affect—which are usually triggered by environmental factors and typically are reported by patients with personality disorders—from more persistent periods of mood polarization. Similarly, anxious patients commonly report having “racing thoughts.”

3. Distinguish patients who have a chronic, ongoing preoccupation with shopping from those who exhibit intermittent periods of excessive shopping and prodigality, which usually are associated with other manic symptoms.³ Spending money in excess is often cited as a classic symptom of mania or hypomania, but it may be an indicator of other conditions, such as compulsive buying.

4. Ask about any increases in goal-directed activity. This is a good way to identify true manic or hypomanic periods. Patients with anxiety or agitated depression may report an increase in psychomotor activity, but this is usually characterized more by restlessness and wandering, and not by a true increase in activity.

Consider a temporary diagnosis

When in doubt, it may be advisable to establish a temporary diagnosis of unspecified mood disorder, until you can learn more about the patient, obtain collateral information from family or friends, and request past medical records.

Illustration: Kimberly Martens for OBG Management

Advances in cancer genetics are rapidly changing how clinicians assess an individual’s risk for breast cancer. ObGyns counsel many women with a personal or family history of the disease, many of whom can benefit from genetics counseling and testing. As patients with a hereditary predisposition to breast cancer are at higher risk and are younger at diagnosis, it is imperative to identify them early so they can benefit from enhanced surveillance, chemoprevention, and discussions regarding risk-reducing surgeries. ObGyns are uniquely poised to identify young women at risk for hereditary cancer syndromes, and they play a crucial role in screening and prevention over the life span.

CASE Patient with breast cancer history asks about screening for her daughters

A 52-year-old woman presents for her annual examination. She underwent breast cancer treatment 10 years earlier and has done well since then. When asked about family history of breast cancer and ethnicity, she reports her mother had breast cancer later in life, and her mother’s father was of Ashkenazi Jewish ancestry.In addition, a maternal uncle had metastatic prostate cancer. You recall that breast cancer diagnosed before age 50 years and Ashkenazi ancestry are “red flags” for a hereditary cancer syndrome. The patient wonders how her daughters should be screened. What do you do next?

Having a risk assessment plan is crucial

Given increasing demands, limited time, and the abundance of information to be discussed with patients, primary care physicians may find it challenging to assess breast cancer risk, consider genetics testing for appropriate individuals, and counsel patients about risk management options. The process has become even more complex since the expansion in genetics knowledge and the advent of multigene panel testing. Not only is risk assessment crucial for this woman and her daughters, and for other patients, but a delay in diagnosing and treating breast cancer in patients with hereditary and familial cancer risks may represent a worrisome new trend in medical litigation.^1,2 Clinicians must have a process in place for assessing risk in all patients and treating them appropriately.

The American Cancer Society (ACS) estimated that 252,710 cases of breast cancer would be diagnosed in 2017, leading to 40,610 deaths.³ Twelve percent to 14% of breast cancers are thought to be related to hereditary cancer predisposition syndromes.^4–8 This means that, every year, almost 35,000 cases of breast cancer are attributable to hereditary risk. These cases can be detected early with enhanced surveillance, which carries the highest chance for cure, or prevented with risk-reducing surgery in identified genetic mutation carriers. Each child of a person with a genetic mutation predisposing to breast cancer has a 50% chance of inheriting the mutation and having a very high risk of cancer.

In this patient’s case, basic information is collected about her cancer-related personal and family history.

Asking a few key questions can help in stratifying risk:

• Have you or anyone in your family had cancer? What type, and at what age?
• If breast cancer, did it involve both breasts, or was it triple-negative?
• Is there a family history of ovarian cancer?
• Is there a family history of male breast cancer?
• Is there a family history of metastatic prostate cancer?
• Are you of Ashkenazi Jewish ethnicity?
• Have you or anyone in your family ever had genetics testing for cancer?

The hallmarks of hereditary cancer are multiple cancers in an individual or family; young age at diagnosis; and ovarian, pancreatic, or another rare cancer. Metastatic prostate cancer was added as a red flag for hereditary risk after a recent large series found that 11.8% of men with metastatic prostate cancer harbor germline mutations.⁹

CASE Continued

On further questioning, the patient reports she had triple-negative (estrogen receptor–, progesterone receptor–, and human epidermal growth factor receptor 2 [HER2]–negative) breast cancer, a feature of patients with germline BRCA1 (breast cancer susceptibility gene 1) mutations.¹⁰ In addition, her Ashkenazi ancestry is concerning, as there is a 1-in-40 chance of carrying 1 of the 3 Ashkenazi founder BRCA mutations.¹¹ Is a genetics consultation needed?

Read about guidelines for referral and testing.

Guidelines for genetics referral and testing

According to the TABLE, which summarizes national guidelines for genetics referral, maternal and paternal family histories are equally important. Our patient was under age 50 at diagnosis, has a history of triple-negative breast cancer, is of Ashkenazi ancestry, and has a family history of metastatic prostate cancer. She meets the criteria for genetics testing, and screening for her daughters most certainly will depend on the findings of that testing. If she carries a BRCA1 mutation, as might be anticipated, each daughter would have a 50% chance of having inherited the mutation. If they carry the mutation as well, they would begin breast magnetic resonance imaging (MRI) screening at age 25.¹² If they decide against genetics testing, they could still undergo MRI screening as untested first-degree relatives of a BRCA carrier, per ACS recommendations.¹³

Integrating evidence and experience

Over the past 10 to 20 years, other breast cancer susceptibility genes (eg, BRCA2, PALB2, CHEK2) have been identified. More recently, next-generation sequencing has become commercially available. Laboratories can use this newer method to sequence multiple genes rapidly and in parallel, and its cost is similar to that of single-syndrome testing.¹⁴ When more than 1 gene can explain an inherited cancer syndrome, multigene panel testing may be more efficient and cost-effective. Use of multigene panel testing is supported in guidelines issued by the National Comprehensive Cancer Network,¹² the American College of Obstetricians and Gynecologists,¹⁵ and other medical societies.

For our patient, the most logical strategy would be to test for the 3 mutations most common in the Ashkenazi population and then, if no mutation is found, perform multigene panel testing.

Formal genetics counseling can be very helpful for a patient, particularly in the era of multigene panel testing.^16,17 A detailed pedigree (family tree) is elicited, and a genetics specialist determines whether testing is indicated and which test is best for the patient. Possible test findings are explained. The patient may be found to have a pathogenic variant with associated increased cancer risk, a negative test result (informative or uninformative), or a variant of uncertain significance (VUS). VUS is a gene mutation identified with an unknown effect on protein function and an unclear association with cancer risk. A finding of VUS may make the patient anxious,¹⁸ create uncertainty in the treating physician,¹⁹ and lead to harmful overtreatment, excessive surveillance, or unnecessary use of a preventive measure.^19–21 Genetics counseling allows the patient, even the patient with VUS, to make appropriate decisions.²² Counseling may also help a patient or family process emotional responses, such as fear and guilt. In addition, counselors are familiar with relevant laws and regulations, such as the Genetic Information Nondiscrimination Act of 2008 (GINA), which protects patients from insurance and employment discrimination. Many professional guidelines recommend providing genetics counseling in conjunction with genetics testing,^12,23 and some insurance companies and some states require counseling for coverage of testing.

Cost of genetics counseling. If patients are concerned about the cost of genetics testing, they can be reassured with the following information^24–26:

• The Patient Protection and Affordable Care Act (ACA) identifies BRCA testing as a preventive service
• Medicare provides coverage for affected patients with a qualifying personal history
• 97% of commercial insurers and most state Medicaid programs provide coverage for hereditary cancer testing
• Most commercial laboratories have affordability programs that may provide additional support.

If a BRCA mutation is found: Many patients question the value of knowing whether they have a BRCA mutation. What our patient, her daughters, and others may not realize is that, if a BRCA mutation is found, breast MRI screening can begin at age 25. Although contrast-enhanced MRI screening is highly sensitive in detecting breast cancer,^27–29 it lacks specificity and commonly yields false positives.

Some patients also worry about overdiagnosis with this highly sensitive test. Many do not realize that preventively prescribed oral contraceptives can reduce the risk of ovarian cancer by 50%, and cosmetically acceptable risk-reducing breast surgeries can reduce the risk by 90%.

Many are unaware of the associated risks with ovarian, prostate, pancreatic, and other cancers; of risk management options; and of assisted reproduction options, such as preimplantation genetics diagnosis, which can prevent the passing of a genetic mutation to future generations. The guidelines on risk management options are increasingly clear and helpful,^12,30–32 and women often turn to their ObGyns for advice about health and prevention.

ObGyns are often the first-line providers for women with a personal or family history of breast cancer. Identification of at-risk patients begins with taking a careful family history and becoming familiar with the rapidly evolving guidelines in this important field. Identification of appropriate candidates for breast cancer genetics testing is a key step toward prevention, value-based care, and avoidance of legal liability.

CASE Resolved

In this case, testing for the 3 common Ashkenazi BRCA founder mutations was negative, and multigene panel testing was also negative. Her husband is not of Ashkenazi Jewish descent and there is no significant family history of cancer on his side. The daughters are advised to begin high-risk screening at the age of 32, 10 years earlier than their mother was diagnosed, but no genetic testing is indicated for them.

Share your thoughts! Send your Letter to the Editor to [email protected]. Please include your name and the city and state in which you practice.

Illustration: Kimberly Martens for OBG Management

Advances in cancer genetics are rapidly changing how clinicians assess an individual’s risk for breast cancer. ObGyns counsel many women with a personal or family history of the disease, many of whom can benefit from genetics counseling and testing. As patients with a hereditary predisposition to breast cancer are at higher risk and are younger at diagnosis, it is imperative to identify them early so they can benefit from enhanced surveillance, chemoprevention, and discussions regarding risk-reducing surgeries. ObGyns are uniquely poised to identify young women at risk for hereditary cancer syndromes, and they play a crucial role in screening and prevention over the life span.

CASE Patient with breast cancer history asks about screening for her daughters

A 52-year-old woman presents for her annual examination. She underwent breast cancer treatment 10 years earlier and has done well since then. When asked about family history of breast cancer and ethnicity, she reports her mother had breast cancer later in life, and her mother’s father was of Ashkenazi Jewish ancestry.In addition, a maternal uncle had metastatic prostate cancer. You recall that breast cancer diagnosed before age 50 years and Ashkenazi ancestry are “red flags” for a hereditary cancer syndrome. The patient wonders how her daughters should be screened. What do you do next?

Having a risk assessment plan is crucial

Given increasing demands, limited time, and the abundance of information to be discussed with patients, primary care physicians may find it challenging to assess breast cancer risk, consider genetics testing for appropriate individuals, and counsel patients about risk management options. The process has become even more complex since the expansion in genetics knowledge and the advent of multigene panel testing. Not only is risk assessment crucial for this woman and her daughters, and for other patients, but a delay in diagnosing and treating breast cancer in patients with hereditary and familial cancer risks may represent a worrisome new trend in medical litigation.^1,2 Clinicians must have a process in place for assessing risk in all patients and treating them appropriately.

The American Cancer Society (ACS) estimated that 252,710 cases of breast cancer would be diagnosed in 2017, leading to 40,610 deaths.³ Twelve percent to 14% of breast cancers are thought to be related to hereditary cancer predisposition syndromes.^4–8 This means that, every year, almost 35,000 cases of breast cancer are attributable to hereditary risk. These cases can be detected early with enhanced surveillance, which carries the highest chance for cure, or prevented with risk-reducing surgery in identified genetic mutation carriers. Each child of a person with a genetic mutation predisposing to breast cancer has a 50% chance of inheriting the mutation and having a very high risk of cancer.

In this patient’s case, basic information is collected about her cancer-related personal and family history.

Asking a few key questions can help in stratifying risk:

• Have you or anyone in your family had cancer? What type, and at what age?
• If breast cancer, did it involve both breasts, or was it triple-negative?
• Is there a family history of ovarian cancer?
• Is there a family history of male breast cancer?
• Is there a family history of metastatic prostate cancer?
• Are you of Ashkenazi Jewish ethnicity?
• Have you or anyone in your family ever had genetics testing for cancer?

The hallmarks of hereditary cancer are multiple cancers in an individual or family; young age at diagnosis; and ovarian, pancreatic, or another rare cancer. Metastatic prostate cancer was added as a red flag for hereditary risk after a recent large series found that 11.8% of men with metastatic prostate cancer harbor germline mutations.⁹

CASE Continued

On further questioning, the patient reports she had triple-negative (estrogen receptor–, progesterone receptor–, and human epidermal growth factor receptor 2 [HER2]–negative) breast cancer, a feature of patients with germline BRCA1 (breast cancer susceptibility gene 1) mutations.¹⁰ In addition, her Ashkenazi ancestry is concerning, as there is a 1-in-40 chance of carrying 1 of the 3 Ashkenazi founder BRCA mutations.¹¹ Is a genetics consultation needed?

Read about guidelines for referral and testing.

Guidelines for genetics referral and testing

According to the TABLE, which summarizes national guidelines for genetics referral, maternal and paternal family histories are equally important. Our patient was under age 50 at diagnosis, has a history of triple-negative breast cancer, is of Ashkenazi ancestry, and has a family history of metastatic prostate cancer. She meets the criteria for genetics testing, and screening for her daughters most certainly will depend on the findings of that testing. If she carries a BRCA1 mutation, as might be anticipated, each daughter would have a 50% chance of having inherited the mutation. If they carry the mutation as well, they would begin breast magnetic resonance imaging (MRI) screening at age 25.¹² If they decide against genetics testing, they could still undergo MRI screening as untested first-degree relatives of a BRCA carrier, per ACS recommendations.¹³

Integrating evidence and experience

Over the past 10 to 20 years, other breast cancer susceptibility genes (eg, BRCA2, PALB2, CHEK2) have been identified. More recently, next-generation sequencing has become commercially available. Laboratories can use this newer method to sequence multiple genes rapidly and in parallel, and its cost is similar to that of single-syndrome testing.¹⁴ When more than 1 gene can explain an inherited cancer syndrome, multigene panel testing may be more efficient and cost-effective. Use of multigene panel testing is supported in guidelines issued by the National Comprehensive Cancer Network,¹² the American College of Obstetricians and Gynecologists,¹⁵ and other medical societies.

For our patient, the most logical strategy would be to test for the 3 mutations most common in the Ashkenazi population and then, if no mutation is found, perform multigene panel testing.

Formal genetics counseling can be very helpful for a patient, particularly in the era of multigene panel testing.^16,17 A detailed pedigree (family tree) is elicited, and a genetics specialist determines whether testing is indicated and which test is best for the patient. Possible test findings are explained. The patient may be found to have a pathogenic variant with associated increased cancer risk, a negative test result (informative or uninformative), or a variant of uncertain significance (VUS). VUS is a gene mutation identified with an unknown effect on protein function and an unclear association with cancer risk. A finding of VUS may make the patient anxious,¹⁸ create uncertainty in the treating physician,¹⁹ and lead to harmful overtreatment, excessive surveillance, or unnecessary use of a preventive measure.^19–21 Genetics counseling allows the patient, even the patient with VUS, to make appropriate decisions.²² Counseling may also help a patient or family process emotional responses, such as fear and guilt. In addition, counselors are familiar with relevant laws and regulations, such as the Genetic Information Nondiscrimination Act of 2008 (GINA), which protects patients from insurance and employment discrimination. Many professional guidelines recommend providing genetics counseling in conjunction with genetics testing,^12,23 and some insurance companies and some states require counseling for coverage of testing.

Cost of genetics counseling. If patients are concerned about the cost of genetics testing, they can be reassured with the following information^24–26:

• The Patient Protection and Affordable Care Act (ACA) identifies BRCA testing as a preventive service
• Medicare provides coverage for affected patients with a qualifying personal history
• 97% of commercial insurers and most state Medicaid programs provide coverage for hereditary cancer testing
• Most commercial laboratories have affordability programs that may provide additional support.

If a BRCA mutation is found: Many patients question the value of knowing whether they have a BRCA mutation. What our patient, her daughters, and others may not realize is that, if a BRCA mutation is found, breast MRI screening can begin at age 25. Although contrast-enhanced MRI screening is highly sensitive in detecting breast cancer,^27–29 it lacks specificity and commonly yields false positives.

Some patients also worry about overdiagnosis with this highly sensitive test. Many do not realize that preventively prescribed oral contraceptives can reduce the risk of ovarian cancer by 50%, and cosmetically acceptable risk-reducing breast surgeries can reduce the risk by 90%.

Many are unaware of the associated risks with ovarian, prostate, pancreatic, and other cancers; of risk management options; and of assisted reproduction options, such as preimplantation genetics diagnosis, which can prevent the passing of a genetic mutation to future generations. The guidelines on risk management options are increasingly clear and helpful,^12,30–32 and women often turn to their ObGyns for advice about health and prevention.

ObGyns are often the first-line providers for women with a personal or family history of breast cancer. Identification of at-risk patients begins with taking a careful family history and becoming familiar with the rapidly evolving guidelines in this important field. Identification of appropriate candidates for breast cancer genetics testing is a key step toward prevention, value-based care, and avoidance of legal liability.

CASE Resolved

In this case, testing for the 3 common Ashkenazi BRCA founder mutations was negative, and multigene panel testing was also negative. Her husband is not of Ashkenazi Jewish descent and there is no significant family history of cancer on his side. The daughters are advised to begin high-risk screening at the age of 32, 10 years earlier than their mother was diagnosed, but no genetic testing is indicated for them.

Share your thoughts! Send your Letter to the Editor to [email protected]. Please include your name and the city and state in which you practice.

Illustration: Kimberly Martens for OBG Management

Advances in cancer genetics are rapidly changing how clinicians assess an individual’s risk for breast cancer. ObGyns counsel many women with a personal or family history of the disease, many of whom can benefit from genetics counseling and testing. As patients with a hereditary predisposition to breast cancer are at higher risk and are younger at diagnosis, it is imperative to identify them early so they can benefit from enhanced surveillance, chemoprevention, and discussions regarding risk-reducing surgeries. ObGyns are uniquely poised to identify young women at risk for hereditary cancer syndromes, and they play a crucial role in screening and prevention over the life span.

CASE Patient with breast cancer history asks about screening for her daughters

A 52-year-old woman presents for her annual examination. She underwent breast cancer treatment 10 years earlier and has done well since then. When asked about family history of breast cancer and ethnicity, she reports her mother had breast cancer later in life, and her mother’s father was of Ashkenazi Jewish ancestry.In addition, a maternal uncle had metastatic prostate cancer. You recall that breast cancer diagnosed before age 50 years and Ashkenazi ancestry are “red flags” for a hereditary cancer syndrome. The patient wonders how her daughters should be screened. What do you do next?

Having a risk assessment plan is crucial

Given increasing demands, limited time, and the abundance of information to be discussed with patients, primary care physicians may find it challenging to assess breast cancer risk, consider genetics testing for appropriate individuals, and counsel patients about risk management options. The process has become even more complex since the expansion in genetics knowledge and the advent of multigene panel testing. Not only is risk assessment crucial for this woman and her daughters, and for other patients, but a delay in diagnosing and treating breast cancer in patients with hereditary and familial cancer risks may represent a worrisome new trend in medical litigation.^1,2 Clinicians must have a process in place for assessing risk in all patients and treating them appropriately.

The American Cancer Society (ACS) estimated that 252,710 cases of breast cancer would be diagnosed in 2017, leading to 40,610 deaths.³ Twelve percent to 14% of breast cancers are thought to be related to hereditary cancer predisposition syndromes.^4–8 This means that, every year, almost 35,000 cases of breast cancer are attributable to hereditary risk. These cases can be detected early with enhanced surveillance, which carries the highest chance for cure, or prevented with risk-reducing surgery in identified genetic mutation carriers. Each child of a person with a genetic mutation predisposing to breast cancer has a 50% chance of inheriting the mutation and having a very high risk of cancer.

In this patient’s case, basic information is collected about her cancer-related personal and family history.

Asking a few key questions can help in stratifying risk:

• Have you or anyone in your family had cancer? What type, and at what age?
• If breast cancer, did it involve both breasts, or was it triple-negative?
• Is there a family history of ovarian cancer?
• Is there a family history of male breast cancer?
• Is there a family history of metastatic prostate cancer?
• Are you of Ashkenazi Jewish ethnicity?
• Have you or anyone in your family ever had genetics testing for cancer?

The hallmarks of hereditary cancer are multiple cancers in an individual or family; young age at diagnosis; and ovarian, pancreatic, or another rare cancer. Metastatic prostate cancer was added as a red flag for hereditary risk after a recent large series found that 11.8% of men with metastatic prostate cancer harbor germline mutations.⁹

CASE Continued

On further questioning, the patient reports she had triple-negative (estrogen receptor–, progesterone receptor–, and human epidermal growth factor receptor 2 [HER2]–negative) breast cancer, a feature of patients with germline BRCA1 (breast cancer susceptibility gene 1) mutations.¹⁰ In addition, her Ashkenazi ancestry is concerning, as there is a 1-in-40 chance of carrying 1 of the 3 Ashkenazi founder BRCA mutations.¹¹ Is a genetics consultation needed?

Read about guidelines for referral and testing.

Guidelines for genetics referral and testing

According to the TABLE, which summarizes national guidelines for genetics referral, maternal and paternal family histories are equally important. Our patient was under age 50 at diagnosis, has a history of triple-negative breast cancer, is of Ashkenazi ancestry, and has a family history of metastatic prostate cancer. She meets the criteria for genetics testing, and screening for her daughters most certainly will depend on the findings of that testing. If she carries a BRCA1 mutation, as might be anticipated, each daughter would have a 50% chance of having inherited the mutation. If they carry the mutation as well, they would begin breast magnetic resonance imaging (MRI) screening at age 25.¹² If they decide against genetics testing, they could still undergo MRI screening as untested first-degree relatives of a BRCA carrier, per ACS recommendations.¹³

Integrating evidence and experience

Over the past 10 to 20 years, other breast cancer susceptibility genes (eg, BRCA2, PALB2, CHEK2) have been identified. More recently, next-generation sequencing has become commercially available. Laboratories can use this newer method to sequence multiple genes rapidly and in parallel, and its cost is similar to that of single-syndrome testing.¹⁴ When more than 1 gene can explain an inherited cancer syndrome, multigene panel testing may be more efficient and cost-effective. Use of multigene panel testing is supported in guidelines issued by the National Comprehensive Cancer Network,¹² the American College of Obstetricians and Gynecologists,¹⁵ and other medical societies.

For our patient, the most logical strategy would be to test for the 3 mutations most common in the Ashkenazi population and then, if no mutation is found, perform multigene panel testing.

Formal genetics counseling can be very helpful for a patient, particularly in the era of multigene panel testing.^16,17 A detailed pedigree (family tree) is elicited, and a genetics specialist determines whether testing is indicated and which test is best for the patient. Possible test findings are explained. The patient may be found to have a pathogenic variant with associated increased cancer risk, a negative test result (informative or uninformative), or a variant of uncertain significance (VUS). VUS is a gene mutation identified with an unknown effect on protein function and an unclear association with cancer risk. A finding of VUS may make the patient anxious,¹⁸ create uncertainty in the treating physician,¹⁹ and lead to harmful overtreatment, excessive surveillance, or unnecessary use of a preventive measure.^19–21 Genetics counseling allows the patient, even the patient with VUS, to make appropriate decisions.²² Counseling may also help a patient or family process emotional responses, such as fear and guilt. In addition, counselors are familiar with relevant laws and regulations, such as the Genetic Information Nondiscrimination Act of 2008 (GINA), which protects patients from insurance and employment discrimination. Many professional guidelines recommend providing genetics counseling in conjunction with genetics testing,^12,23 and some insurance companies and some states require counseling for coverage of testing.

Cost of genetics counseling. If patients are concerned about the cost of genetics testing, they can be reassured with the following information^24–26:

• The Patient Protection and Affordable Care Act (ACA) identifies BRCA testing as a preventive service
• Medicare provides coverage for affected patients with a qualifying personal history
• 97% of commercial insurers and most state Medicaid programs provide coverage for hereditary cancer testing
• Most commercial laboratories have affordability programs that may provide additional support.

If a BRCA mutation is found: Many patients question the value of knowing whether they have a BRCA mutation. What our patient, her daughters, and others may not realize is that, if a BRCA mutation is found, breast MRI screening can begin at age 25. Although contrast-enhanced MRI screening is highly sensitive in detecting breast cancer,^27–29 it lacks specificity and commonly yields false positives.

Some patients also worry about overdiagnosis with this highly sensitive test. Many do not realize that preventively prescribed oral contraceptives can reduce the risk of ovarian cancer by 50%, and cosmetically acceptable risk-reducing breast surgeries can reduce the risk by 90%.

Many are unaware of the associated risks with ovarian, prostate, pancreatic, and other cancers; of risk management options; and of assisted reproduction options, such as preimplantation genetics diagnosis, which can prevent the passing of a genetic mutation to future generations. The guidelines on risk management options are increasingly clear and helpful,^12,30–32 and women often turn to their ObGyns for advice about health and prevention.

ObGyns are often the first-line providers for women with a personal or family history of breast cancer. Identification of at-risk patients begins with taking a careful family history and becoming familiar with the rapidly evolving guidelines in this important field. Identification of appropriate candidates for breast cancer genetics testing is a key step toward prevention, value-based care, and avoidance of legal liability.

CASE Resolved

In this case, testing for the 3 common Ashkenazi BRCA founder mutations was negative, and multigene panel testing was also negative. Her husband is not of Ashkenazi Jewish descent and there is no significant family history of cancer on his side. The daughters are advised to begin high-risk screening at the age of 32, 10 years earlier than their mother was diagnosed, but no genetic testing is indicated for them.

Share your thoughts! Send your Letter to the Editor to [email protected]. Please include your name and the city and state in which you practice.

A meaningful evolution has occurred over the past 30 years in the evaluation of ovarian tumors. In the 1980s, any palpable ovarian tumor was recommended for surgical removal.¹ In the early 2000s, studies showed that unilocular cysts were at very low risk for malignancy, and surveillance was recommended.² In the following decade, septate cysts were added to the list of ovarian tumors unlikely to be malignant, and nonsurgical therapy was suggested.³ It is estimated that 10% of women will undergo surgery for an adnexal mass in their lifetime, despite the fact that only 1 in 6 (13%–21%) of these masses is found to be malignant.^4,5

A comprehensive, morphology-based pelvic ultrasonography is the first and most important step in evaluating an ovarian tumor’s risk of malignancy to determine whether surgery or surveillance is required.

Ovarian cancer continues to be the leading cause of gynecologic cancer death. Despite achieving superior surgical and cancer outcomes, a gynecologic oncologist performs only 40% of the initial ovarian cancer surgeries.⁶ Premenopausal and menopausal ovarian tumors are different in cause and consequence. Only 15% of premenopausal tumors are malignant, most commonly germ cell tumors, borderline ovarian tumors, and epithelial ovarian cancers. Tumors in menopausal women are less common but are more likely to be malignant. In actuality, up to 50% of tumors in this population are malignant. The most common of these malignancies are epithelial ovarian cancers, cancers metastatic to the ovary, and malignant stromal tumors.

Effective and evidence-based preoperative evaluations are available to help the clinician estimate a tumor’s risk of malignancy and determine which tumors are appropriate for referral to a specialist for surgery.

The actual incidence and prevalence of ovarian tumors are not known. From a review of almost 40,000 ultrasonography scans performed in the University of Kentucky Ovarian Cancer Screening Program, the estimated incidence and prevalence of ovarian abnormalities are 8.2 per 100 women annuallyand 17%, respectively.⁷ Seventy percent of these abnormalities have a unilocular or simple septate morphology and are at low risk for malignancy.⁷ The remaining 30% of abnormalities are high risk, although this represents only 9% of the total population evaluated. Since the vast majority of these abnormalities are expected to be asymptomatic, most will go unrecognized in the general population. For women who have an ovarian abnormality on ultrasonography, the majority will be at low risk for malignancy and will not require surgery.

Ovarian ultrasonography plus morphologic scoring comprise a comprehensive approach

The recently published recommendations of the First International Consensus Conference report on adnexal masses are summarized in TABLE 1.⁸ The expert panel reviewed the evidence and concluded that effective ultrasonography strategies exist and are well validated, and that low-risk asymptomatic ovarian cysts do not require surgical removal.

While no single ultrasonographic findingcan differentiate a benign from a malignant mass, morphologic scoring systems improve our ability to estimate a tumor’s malignant potential. In the United States, most practitioners in women’s health have ready access to gynecologic ultrasonography, but individual training and proficiency vary. Since not everyone is an expert sonographer, it is useful to employ an objective strategy when evaluating an ovarian tumor. The focus of a comprehensive ovarian ultrasonography is to recognize morphologic patterns that reflect a tumor’s malignant potential. While tumor volume is useful, tumor morphology is the most prognostic feature.

International Ovarian Tumor Analysis group

The International Ovarian Tumor Analysis (IOTA) group has published extensively on sonographic definitions and patterns that categorize tumors based on appearance.⁹ Simple rules and the ADNEX risk model are 2 of the group’s approaches (FIGURE 1).^10,11 Both methods have been validated as effective for differentiating benign from malignant ovarian tumors, but neither has been used to study serial changes in ovarian morphology.

Regardless of the strategy employed, 25% of ovarian ultrasonography evaluations will be interpreted as “indeterminate” or “risk unknown.”¹⁰ The IOTA strategies have been successfully used in Europe for years, but they have not yet been studied or adopted in the United States.

Kentucky morphology index

The morphology index (MI) from the University of Kentucky is an ultrasonography-based scoring system that combines tumor volume and tumor structure into a simple and effective index with a score ranging from 0 to 10 (FIGURE 2).¹² A rising Kentucky MI score has a linear and predictable increase in the risk of ovarian malignancy. In a review of almost 40,000 sonograms, 85% of the malignancies had an MI score of 5 or greater (TABLE 2).¹² Using this as a cutoff, the sensitivity and specificity for predicting malignancy was 86% and 98%, respectively.¹²