Commentary

Few of my readers were around when Medicare was signed into law in 1965 by President Lyndon Johnson. Mr. Johnson was into his first elected term as president, having first taken the oath of office with the assassination of John F. Kennedy in November 1963.

Hardly a darling of the liberal left, he was maligned as the perpetrator, if not for the expansion, of the Vietnam War. He was elected with the largest presidential plurality in history, receiving 61% of the votes, and he carried with him a solid Democratic Congress bolstered by a large block of solid Southern Democrats, a firmament from which he had emerged. He can be credited for the most far-reaching social legislation of the 20th century, second only to Franklin Delano Roosevelt of the 1930s. Johnson was able to move the Civil Rights Act of 1964 and the Voting Rights Act and Medicare Act through Congress in 1965, the latter of which we celebrate this year.

At the time of passage of Medicare, 35% of Americans over 65 had no health insurance, either because they found insurance unaffordable or because of preexisting illness. Health insurance premiums for the elderly cost roughly three times more than did those for younger individuals. With many of the elderly living on Social Security alone, health insurance was an impossibility. If they needed care, they might find it at the emergency department of their local hospitals.

The battle for the passage of Medicare was formidable. In contrast to the passive role of the American Medical Association in the passage of the Affordable Care Act, Medicare was, to put it mildly, vigorously opposed by most doctors and by the AMA, which viewed it as the harbinger of long-anticipated socialized medicine. It ended up being far from it.

Medicare provided a pathway to an economic bonanza for the practicing physician and to hospitals that they could never have imagined. It immediately expanded the patient population and allowed enterprising and not-so-enterprising doctors and hospitals to run up the costs of health care by strengthening the fee-for-service style of medical care. Doctors, hospitals, and patients had no concern for cost: Medicare paid for everything.

Hospitals found Medicare a ready source of income. Doctor and hospital bills were based on the usual cost to each in their respective communities. Medical educators as well as house staff also saw their income lifted as a result of the federal government’s paying for a large part if not all of the cost of house staff education. Even the small number of physicians who opted out of Medicare, because of the red tape or to preserve their independence from the federal government, benefited. Their fees increased as the payment schedules of Medicare increased in their communities.

One of the by-products of Medicare was the end of hospital segregation. For those of you who were not around then, you can imagine what an impact that had on hospitals and doctors in both the North and the South.

Over time, Medicare expanded its footprint to include treatment of chronic kidney disease at any age, as well as drug coverage. I would guess that most Americans over 65 (this writer included) love Medicare. And doctors? Well, they still grumble about it.

With the recent readjustment of physicians’ Medicare reimbursement rates, the door has been opened to new initiatives based on quality of care. No matter what your political persuasion, it is clear that Americans cannot afford Medicare as we know it. Physicians undoubtedly will find their fee-for-service style of reimbursement curtailed as we learn the definition of “quality care standards.” Quality standards will not only define clinical performance, but will also include cost of rendering that care. So long to the world of fee-for-service reimbursement.

Dr. Goldstein, medical editor of Cardiology News, is professor of medicine at Wayne State University and division head emeritus of cardiovascular medicine at Henry Ford Hospital, both in Detroit. He is on data safety monitoring committees for the National Institutes of Health and several pharmaceutical companies.

Few of my readers were around when Medicare was signed into law in 1965 by President Lyndon Johnson. Mr. Johnson was into his first elected term as president, having first taken the oath of office with the assassination of John F. Kennedy in November 1963.

Hardly a darling of the liberal left, he was maligned as the perpetrator, if not for the expansion, of the Vietnam War. He was elected with the largest presidential plurality in history, receiving 61% of the votes, and he carried with him a solid Democratic Congress bolstered by a large block of solid Southern Democrats, a firmament from which he had emerged. He can be credited for the most far-reaching social legislation of the 20th century, second only to Franklin Delano Roosevelt of the 1930s. Johnson was able to move the Civil Rights Act of 1964 and the Voting Rights Act and Medicare Act through Congress in 1965, the latter of which we celebrate this year.

At the time of passage of Medicare, 35% of Americans over 65 had no health insurance, either because they found insurance unaffordable or because of preexisting illness. Health insurance premiums for the elderly cost roughly three times more than did those for younger individuals. With many of the elderly living on Social Security alone, health insurance was an impossibility. If they needed care, they might find it at the emergency department of their local hospitals.

The battle for the passage of Medicare was formidable. In contrast to the passive role of the American Medical Association in the passage of the Affordable Care Act, Medicare was, to put it mildly, vigorously opposed by most doctors and by the AMA, which viewed it as the harbinger of long-anticipated socialized medicine. It ended up being far from it.

Medicare provided a pathway to an economic bonanza for the practicing physician and to hospitals that they could never have imagined. It immediately expanded the patient population and allowed enterprising and not-so-enterprising doctors and hospitals to run up the costs of health care by strengthening the fee-for-service style of medical care. Doctors, hospitals, and patients had no concern for cost: Medicare paid for everything.

Hospitals found Medicare a ready source of income. Doctor and hospital bills were based on the usual cost to each in their respective communities. Medical educators as well as house staff also saw their income lifted as a result of the federal government’s paying for a large part if not all of the cost of house staff education. Even the small number of physicians who opted out of Medicare, because of the red tape or to preserve their independence from the federal government, benefited. Their fees increased as the payment schedules of Medicare increased in their communities.

One of the by-products of Medicare was the end of hospital segregation. For those of you who were not around then, you can imagine what an impact that had on hospitals and doctors in both the North and the South.

Over time, Medicare expanded its footprint to include treatment of chronic kidney disease at any age, as well as drug coverage. I would guess that most Americans over 65 (this writer included) love Medicare. And doctors? Well, they still grumble about it.

With the recent readjustment of physicians’ Medicare reimbursement rates, the door has been opened to new initiatives based on quality of care. No matter what your political persuasion, it is clear that Americans cannot afford Medicare as we know it. Physicians undoubtedly will find their fee-for-service style of reimbursement curtailed as we learn the definition of “quality care standards.” Quality standards will not only define clinical performance, but will also include cost of rendering that care. So long to the world of fee-for-service reimbursement.

Dr. Goldstein, medical editor of Cardiology News, is professor of medicine at Wayne State University and division head emeritus of cardiovascular medicine at Henry Ford Hospital, both in Detroit. He is on data safety monitoring committees for the National Institutes of Health and several pharmaceutical companies.

Few of my readers were around when Medicare was signed into law in 1965 by President Lyndon Johnson. Mr. Johnson was into his first elected term as president, having first taken the oath of office with the assassination of John F. Kennedy in November 1963.

Hardly a darling of the liberal left, he was maligned as the perpetrator, if not for the expansion, of the Vietnam War. He was elected with the largest presidential plurality in history, receiving 61% of the votes, and he carried with him a solid Democratic Congress bolstered by a large block of solid Southern Democrats, a firmament from which he had emerged. He can be credited for the most far-reaching social legislation of the 20th century, second only to Franklin Delano Roosevelt of the 1930s. Johnson was able to move the Civil Rights Act of 1964 and the Voting Rights Act and Medicare Act through Congress in 1965, the latter of which we celebrate this year.

At the time of passage of Medicare, 35% of Americans over 65 had no health insurance, either because they found insurance unaffordable or because of preexisting illness. Health insurance premiums for the elderly cost roughly three times more than did those for younger individuals. With many of the elderly living on Social Security alone, health insurance was an impossibility. If they needed care, they might find it at the emergency department of their local hospitals.

The battle for the passage of Medicare was formidable. In contrast to the passive role of the American Medical Association in the passage of the Affordable Care Act, Medicare was, to put it mildly, vigorously opposed by most doctors and by the AMA, which viewed it as the harbinger of long-anticipated socialized medicine. It ended up being far from it.

Medicare provided a pathway to an economic bonanza for the practicing physician and to hospitals that they could never have imagined. It immediately expanded the patient population and allowed enterprising and not-so-enterprising doctors and hospitals to run up the costs of health care by strengthening the fee-for-service style of medical care. Doctors, hospitals, and patients had no concern for cost: Medicare paid for everything.

Hospitals found Medicare a ready source of income. Doctor and hospital bills were based on the usual cost to each in their respective communities. Medical educators as well as house staff also saw their income lifted as a result of the federal government’s paying for a large part if not all of the cost of house staff education. Even the small number of physicians who opted out of Medicare, because of the red tape or to preserve their independence from the federal government, benefited. Their fees increased as the payment schedules of Medicare increased in their communities.

One of the by-products of Medicare was the end of hospital segregation. For those of you who were not around then, you can imagine what an impact that had on hospitals and doctors in both the North and the South.

Over time, Medicare expanded its footprint to include treatment of chronic kidney disease at any age, as well as drug coverage. I would guess that most Americans over 65 (this writer included) love Medicare. And doctors? Well, they still grumble about it.

With the recent readjustment of physicians’ Medicare reimbursement rates, the door has been opened to new initiatives based on quality of care. No matter what your political persuasion, it is clear that Americans cannot afford Medicare as we know it. Physicians undoubtedly will find their fee-for-service style of reimbursement curtailed as we learn the definition of “quality care standards.” Quality standards will not only define clinical performance, but will also include cost of rendering that care. So long to the world of fee-for-service reimbursement.

Dr. Goldstein, medical editor of Cardiology News, is professor of medicine at Wayne State University and division head emeritus of cardiovascular medicine at Henry Ford Hospital, both in Detroit. He is on data safety monitoring committees for the National Institutes of Health and several pharmaceutical companies.

The results of the 2015 National Residency Match Program were announced on March 20. For family medicine, the glass was either half empty or half full, depending on your point of view.

On the plus side, 84 more family medicine positions were offered compared to 2014 (3216 vs 3132) and 60 more positions were filled, for a total of 3060 new family medicine residents in 2015.¹ This was far more than matched in gloomy 2009, when only 2555 residents chose family medicine. On the negative side of the balance sheet, there will be 233 fewer family medicine residents this year than matched at the peak of medical student interest in family medicine in 1998.

I’m a glass half full kind of guy, so I am delighted that the trend of increased medical student interest in family medicine continues. According to Merritt Hawkins, a national recruitment firm, family medicine has been the top recruited specialty for several years. The firm reports that starting salaries for family physicians increased by nearly 12% from 2010/11 to 2013/14, which was a higher rate than that of most other specialties.² So there is reason to be optimistic about the future of our specialty.

Our monthly 5-question online quiz can help residents study for their certification exam.

However, to be card-carrying family physicians, our new residents must take the American Board of Family Medicine certification exam, and not all pass on their first attempt. A 2013 study of family medicine residency graduates found that only 86% of graduates passed the board exam on their first try.³

We can help. In addition to the evidence-based reviews published in The Journal of Family Practice (JFP), we have launched a new feature called Residents’ Rapid Review (RRR) to provide an additional resource for residents.

RRR is a monthly 5-question evidence-based quiz prepared by primary care faculty, including current and former residency program directors. After residents click on their answer, the system lets them know whether they’re right and provides the correct answer with an explanation and references. Monthly notifications are sent out to all jfponline.com registered users alerting them that a new quiz is available. (Not a registered user on the site? Sign up at jfponline.com/residents_reg.)

Getting ready for the recertification exam? The RRR quizzes can help you, too. Check out the latest quiz, today!

The results of the 2015 National Residency Match Program were announced on March 20. For family medicine, the glass was either half empty or half full, depending on your point of view.

On the plus side, 84 more family medicine positions were offered compared to 2014 (3216 vs 3132) and 60 more positions were filled, for a total of 3060 new family medicine residents in 2015.¹ This was far more than matched in gloomy 2009, when only 2555 residents chose family medicine. On the negative side of the balance sheet, there will be 233 fewer family medicine residents this year than matched at the peak of medical student interest in family medicine in 1998.

I’m a glass half full kind of guy, so I am delighted that the trend of increased medical student interest in family medicine continues. According to Merritt Hawkins, a national recruitment firm, family medicine has been the top recruited specialty for several years. The firm reports that starting salaries for family physicians increased by nearly 12% from 2010/11 to 2013/14, which was a higher rate than that of most other specialties.² So there is reason to be optimistic about the future of our specialty.

Our monthly 5-question online quiz can help residents study for their certification exam.

However, to be card-carrying family physicians, our new residents must take the American Board of Family Medicine certification exam, and not all pass on their first attempt. A 2013 study of family medicine residency graduates found that only 86% of graduates passed the board exam on their first try.³

We can help. In addition to the evidence-based reviews published in The Journal of Family Practice (JFP), we have launched a new feature called Residents’ Rapid Review (RRR) to provide an additional resource for residents.

RRR is a monthly 5-question evidence-based quiz prepared by primary care faculty, including current and former residency program directors. After residents click on their answer, the system lets them know whether they’re right and provides the correct answer with an explanation and references. Monthly notifications are sent out to all jfponline.com registered users alerting them that a new quiz is available. (Not a registered user on the site? Sign up at jfponline.com/residents_reg.)

Getting ready for the recertification exam? The RRR quizzes can help you, too. Check out the latest quiz, today!

The results of the 2015 National Residency Match Program were announced on March 20. For family medicine, the glass was either half empty or half full, depending on your point of view.

On the plus side, 84 more family medicine positions were offered compared to 2014 (3216 vs 3132) and 60 more positions were filled, for a total of 3060 new family medicine residents in 2015.¹ This was far more than matched in gloomy 2009, when only 2555 residents chose family medicine. On the negative side of the balance sheet, there will be 233 fewer family medicine residents this year than matched at the peak of medical student interest in family medicine in 1998.

I’m a glass half full kind of guy, so I am delighted that the trend of increased medical student interest in family medicine continues. According to Merritt Hawkins, a national recruitment firm, family medicine has been the top recruited specialty for several years. The firm reports that starting salaries for family physicians increased by nearly 12% from 2010/11 to 2013/14, which was a higher rate than that of most other specialties.² So there is reason to be optimistic about the future of our specialty.

Our monthly 5-question online quiz can help residents study for their certification exam.

However, to be card-carrying family physicians, our new residents must take the American Board of Family Medicine certification exam, and not all pass on their first attempt. A 2013 study of family medicine residency graduates found that only 86% of graduates passed the board exam on their first try.³

We can help. In addition to the evidence-based reviews published in The Journal of Family Practice (JFP), we have launched a new feature called Residents’ Rapid Review (RRR) to provide an additional resource for residents.

RRR is a monthly 5-question evidence-based quiz prepared by primary care faculty, including current and former residency program directors. After residents click on their answer, the system lets them know whether they’re right and provides the correct answer with an explanation and references. Monthly notifications are sent out to all jfponline.com registered users alerting them that a new quiz is available. (Not a registered user on the site? Sign up at jfponline.com/residents_reg.)

Getting ready for the recertification exam? The RRR quizzes can help you, too. Check out the latest quiz, today!

National societies agree on the value of mammographic screening at age 50 through 69 (though the frequency is still debated), but there is no consensus about whether to screen at age 40 through 49, or age 70 and older. The US Preventive Services Task Force (USPSTF) recommends against routinely screening women age 40 through 49, while the American Academy of Family Physicians and the American College of Physicians recommend screening every 1 to 2 years for women in this age group. The American Cancer Society, the American Medical Association, the National Cancer Institute, the American College of Radiology, and the American Congress of Obstetricians and Gynecologists recommend yearly mammography starting at age 40.¹

See opposing commentary

Besides female sex, the major risk factor for breast cancer is increasing age. Thus, women in their 40s are at significantly lower risk of breast cancer than those in their 50s. As emerging evidence focuses on the potential harms and benefits from screening, we must question the practice of annual screening starting at age 40.

DOES MAMMOGRAPHIC SCREENING SAVE LIVES?

The main goal of screening for any type of cancer is to reduce the death rate. A 2014 meta-analysis of randomized controlled trials found a 15% to 20% relative decrease in the breast cancer mortality rate with screening mammography, approximately 15% for women in their 40s and 32% for women in their 60s.² Since the prevalence of breast cancer is lower in younger women, many more women in their 40s must be screened to prevent one breast cancer death. For women age 60 to 69, 377 must be screened to prevent one breast cancer death, whereas for women age 39 to 49 the number is 1,904.³

In view of potential harm, we question starting annual screening at age 40

Whether screening for breast cancer reduces the death rate has been questioned following the 2014 publication of 25-year follow-up data from the Canadian National Breast Screening Study.⁴ This randomized controlled trial of screening mammography and clinical breast examination, launched in 1980, involved 89,835 women and 5 years of screening. Women age 40 to 49 were randomly assigned to undergo either five annual mammographic screenings and annual clinical breast examinations or no mammography and a single clinical breast examination, followed by usual care in the community. Those age 50 to 59 received annual clinical breast examinations and were randomized to either mammography or no mammography.

During 25 years of follow-up, 3,250 women in the mammography group and 3,133 in the control group were diagnosed with breast cancer, and 500 and 505, respectively, died of breast cancer. No difference in mortality rate was found between the mammography and control groups (hazard ratio 0.99, 95% confidence interval 0.88–1.12), and the findings in both age cohorts were similar.⁴

Criticisms of this study include that it was performed using outdated imaging technology, and that a significant proportion of the control group also received mammography, although it is also possible that the mortality benefit from mammographic screening alone may not be as high as once predicted.

Reduction in breast cancer mortality is likely from a combination of screening mammography and better treatment. The number of women presenting with late-stage cancers has decreased in the past 3 decades, but only slightly; and most of the decrease has been in regional, node-positive disease, a stage that can now often be treated successfully (the expected 5-year survival rate is 85% in women age 40 or older).⁵ For women with estrogen receptor-positive tumors, the combination of hormonal therapy and adjuvant chemotherapy has reduced the death rate by half.⁶

It has been 50 years since a large randomized controlled trial of mammographic screening has been done in the United States. Thus, further study is needed to understand whether screening is less valuable now that better treatments are available.

DOES MAMMOGRAPHIC SCREENING REDUCE LATE-STAGE CANCERS?

To be effective, screening must detect disease at an earlier, more curable stage. Although screening mammography has substantially increased the number of early-stage breast cancers detected, it has only marginally decreased the rate of diagnosis of late-stage cancers.⁵

It has been 50 years since the last large randomized US trial of mammography

The National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) data⁵ show that between 1976 and 2008 screening mammography was associated with a doubling in early-stage breast cancer cases detected (from 112 to 234 cases per 100,000 women per year, an absolute increase of 122 cases per 100,000 per year). In contrast, late-stage cancer diagnoses decreased by 8% (from 102 to 94 cases per 100,000 women per year, or an absolute decrease of 8 per 100,000 women per year). Assuming a constant underlying disease burden, only 8 of the 122 early-stage cancers diagnosed would be expected to progress to advanced disease, suggesting that the rest would have never harmed these women—ie, they were overdiagnosed. The authors estimated that in 2008, breast cancer was overdiagnosed in more than 70,000 women, accounting for 31% of all diagnosed breast cancers.⁵

HARMS OF OVERDIAGNOSIS

Based on SEER data, Bleyer and Welch⁵ estimated that more than 1 million US women may have been overdiagnosed with breast cancer in the past 3 decades. Many women in this situation subsequently undergo surgery, radiation therapy, hormonal therapy, chemotherapy, or a combination of these for a cancer that may never become clinically significant. Until we can differentiate deadly from indolent cancers, highly sensitive screening tests will increase the risk of overtreatment.

Breast cancer has increased since the 1990s, mostly from detection of more cases of early-stage cancer and ductal carcinoma in situ

Breast cancer has increased in incidence since the 1990s, mostly from the detection of more early-stage cancer or ductal carcinoma in situ (DCIS). Rare before widespread screening, DCIS now accounts for 20% to 30% of all breast cancer diagnoses.^6,7 However, DCIS is not always a precursor to invasive cancer: untreated, it progresses to invasive disease in half of cases or fewer. Because DCIS is usually diagnosed only with mammography, its incidence has been steadily on the rise since screening became widespread.¹

Welch and Passow⁶ reviewed the available evidence and attempted to provide a range of estimates for three outcomes important to the mammography decision: breast cancer deaths avoided, false alarms, and overdiagnosis. For every 1,000 US women screened yearly for a decade starting at age 50, an estimated 0.3 to 3.2 avoided breast cancer death, 490 to 670 had at least one false alarm, and 3 to 14 were overdiagnosed and treated needlessly.

Esserman et al⁷ calculated that in women age 50 to 70, prevention of one breast cancer death would require that 838 women be screened for 6 years, leading to 5,866 screening visits, 535 recalls, 90 biopsies, and 24 cancers treated (18 invasive, 6 DCIS).

SCREENING EVERY YEAR VS EVERY 2 YEARS

Also controversial is whether screening mammography should be done annually or every 2 years. For women in their 50s, the American Cancer Society recommends mammography every year, the American College of Physicians and American Academy of Family Physicians recommend it every 1 to 2 years, and the USPSTF recommends it every 2 years.

A prospective analysis of 11,474 women with breast cancer and 922,624 controls⁸ found that performing mammography every 2 years instead of annually for women age 50 to 74 did not increase the risk of advanced-stage or large-size tumors regardless of breast density or hormone therapy use. But women undergoing annual mammography had a higher risk of false-positive results and biopsy recommendations.⁸ Women age 40 to 49 with extremely dense breasts were the only subgroup who derived additional benefit from annual screening, as they had a higher risk of advanced-stage cancer if they were screened every 2 years instead of yearly (odds ratio [OR] 1.89; 95% CI 1.06–3.39) and a higher risk of larger tumors (OR 2.39; 95% CI 1.37–4.18). However, the probability of a false-positive result in these younger women undergoing annual mammography was also very high at 65.5%.⁸

For most women in their 40s (other than those with extremely dense breasts) and 50s, biennial and annual mammography were associated with a similar risk of advanced-stage disease. Women with fatty breasts are at low risk of breast cancer regardless of other risk factors and did not appear to benefit from annual screening.⁸ The 12% to 15% of women in their 40s with extremely dense breasts (whose risk of breast cancer is similar to that in average-risk women in their 50s) should decide if the added benefit of annual screening is outweighed by the additional harms, including doubling the number of mammograms, as well as more false-positive results and breast biopsy recommendations.⁸

Mandelblatt et al⁹ statistically evaluated 20 screening strategies, ie, screening every year or every 2 years, and starting and stopping at various ages. On average, screening every 2 years was 81% as beneficial as annual screening but caused only about half as many false-positive results. Women age 50 through 69 who were screened every 2 years achieved a median 16.5% (range 15%–23%) reduction in breast cancer deaths compared with no screening. Initiating screening every 2 years at age 40 reduced the death rate by an additional 3% (range 1%–6%) compared with starting at age 50. Not surprisingly, starting screening at age 40 consumed more resources and yielded more false-positive results. After age 69, screening every 2 years yielded some additional mortality reduction in all models, but overdiagnosis increased most substantially at older ages, as the ratio of slow- to fast-growing tumors increases with age. The authors concluded that screening every 2 years achieves most of the benefit of annual screening with less harm.

FALSE-POSITIVE RESULTS AND ANXIETY

False-positive results on mammography can increase distress and anxiety about breast cancer and perceived breast cancer risk in some women.³ After 10 years of annual screening, more than half of women receive at least one false-positive recall, and 7% to 9% receive a false-positive biopsy recommendation. It is helpful for women to understand this risk when deciding whether to start mammographic screening.¹⁰

OUR VIEWS

There are two major issues to address in clinical practice regarding mammographic screening: at what age to start, and how often to screen. For years, women have been instructed to start annual mammographic screening at age 40, and such established patterns can be difficult to change.

Women need to be aware of the benefits and risks to make an informed decision

When deciding whether to have a mammogram at age 40, women should be aware of the full range of risks and benefits. Assessing a woman’s individual risk of breast cancer (based on family history and number and age of pregnancies) can be an important starting point for assessing the potential benefits and risks of screening.

Although a shared decision-making approach is intuitively appealing, it takes much more time than simply ordering a mammogram. Time constraints during a medical appointment may make it challenging to have a prolonged discussion about the pros and cons of screening. Patient education materials about the risks vs benefits of screening initiation may be useful, and because the decision does not usually need to be made urgently, women can be given the opportunity to consider the decision outside of the primary care appointment.

The issue of annual vs biennial screening presents an additional challenge, because women have come to expect annual screening. Studies show that the only subgroup of women who appear to benefit from annual screening are those in their 40s with dense breasts. Although breast cancer is rarer in younger women, when it does develop, it is often more aggressive, so offering annual screening to this subpopulation may make sense. For all other women, since there is no evidence that annual mammography offers clinical benefit over biennial screening, clinicians can be comfortable with offering screening every 2 years.

Future research must focus on developing better tools for differentiating women who are at higher vs lower risk for breast cancer and on developing methods to determine which DCIS cancers are more likely to be indolent and therefore amenable to watchful waiting.

In the interim, we must continue to identify women at high risk who will benefit from magnetic resonance imaging, genetic testing, and prophylactic medications, in accordance with USPSTF recommendations. Women with new breast symptoms or concerns should continue to undergo evaluation with diagnostic imaging, including mammography. However, for most women who are at average risk and have no symptoms, we must ensure that they are fully aware of the possible benefits and risks of screening mammography so that they can make an informed decision about when to start screening and how often to be screened.

National societies agree on the value of mammographic screening at age 50 through 69 (though the frequency is still debated), but there is no consensus about whether to screen at age 40 through 49, or age 70 and older. The US Preventive Services Task Force (USPSTF) recommends against routinely screening women age 40 through 49, while the American Academy of Family Physicians and the American College of Physicians recommend screening every 1 to 2 years for women in this age group. The American Cancer Society, the American Medical Association, the National Cancer Institute, the American College of Radiology, and the American Congress of Obstetricians and Gynecologists recommend yearly mammography starting at age 40.¹

See opposing commentary

Besides female sex, the major risk factor for breast cancer is increasing age. Thus, women in their 40s are at significantly lower risk of breast cancer than those in their 50s. As emerging evidence focuses on the potential harms and benefits from screening, we must question the practice of annual screening starting at age 40.

DOES MAMMOGRAPHIC SCREENING SAVE LIVES?

The main goal of screening for any type of cancer is to reduce the death rate. A 2014 meta-analysis of randomized controlled trials found a 15% to 20% relative decrease in the breast cancer mortality rate with screening mammography, approximately 15% for women in their 40s and 32% for women in their 60s.² Since the prevalence of breast cancer is lower in younger women, many more women in their 40s must be screened to prevent one breast cancer death. For women age 60 to 69, 377 must be screened to prevent one breast cancer death, whereas for women age 39 to 49 the number is 1,904.³

In view of potential harm, we question starting annual screening at age 40

Whether screening for breast cancer reduces the death rate has been questioned following the 2014 publication of 25-year follow-up data from the Canadian National Breast Screening Study.⁴ This randomized controlled trial of screening mammography and clinical breast examination, launched in 1980, involved 89,835 women and 5 years of screening. Women age 40 to 49 were randomly assigned to undergo either five annual mammographic screenings and annual clinical breast examinations or no mammography and a single clinical breast examination, followed by usual care in the community. Those age 50 to 59 received annual clinical breast examinations and were randomized to either mammography or no mammography.

During 25 years of follow-up, 3,250 women in the mammography group and 3,133 in the control group were diagnosed with breast cancer, and 500 and 505, respectively, died of breast cancer. No difference in mortality rate was found between the mammography and control groups (hazard ratio 0.99, 95% confidence interval 0.88–1.12), and the findings in both age cohorts were similar.⁴

Criticisms of this study include that it was performed using outdated imaging technology, and that a significant proportion of the control group also received mammography, although it is also possible that the mortality benefit from mammographic screening alone may not be as high as once predicted.

Reduction in breast cancer mortality is likely from a combination of screening mammography and better treatment. The number of women presenting with late-stage cancers has decreased in the past 3 decades, but only slightly; and most of the decrease has been in regional, node-positive disease, a stage that can now often be treated successfully (the expected 5-year survival rate is 85% in women age 40 or older).⁵ For women with estrogen receptor-positive tumors, the combination of hormonal therapy and adjuvant chemotherapy has reduced the death rate by half.⁶

It has been 50 years since a large randomized controlled trial of mammographic screening has been done in the United States. Thus, further study is needed to understand whether screening is less valuable now that better treatments are available.

DOES MAMMOGRAPHIC SCREENING REDUCE LATE-STAGE CANCERS?

To be effective, screening must detect disease at an earlier, more curable stage. Although screening mammography has substantially increased the number of early-stage breast cancers detected, it has only marginally decreased the rate of diagnosis of late-stage cancers.⁵

It has been 50 years since the last large randomized US trial of mammography

The National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) data⁵ show that between 1976 and 2008 screening mammography was associated with a doubling in early-stage breast cancer cases detected (from 112 to 234 cases per 100,000 women per year, an absolute increase of 122 cases per 100,000 per year). In contrast, late-stage cancer diagnoses decreased by 8% (from 102 to 94 cases per 100,000 women per year, or an absolute decrease of 8 per 100,000 women per year). Assuming a constant underlying disease burden, only 8 of the 122 early-stage cancers diagnosed would be expected to progress to advanced disease, suggesting that the rest would have never harmed these women—ie, they were overdiagnosed. The authors estimated that in 2008, breast cancer was overdiagnosed in more than 70,000 women, accounting for 31% of all diagnosed breast cancers.⁵

HARMS OF OVERDIAGNOSIS

Based on SEER data, Bleyer and Welch⁵ estimated that more than 1 million US women may have been overdiagnosed with breast cancer in the past 3 decades. Many women in this situation subsequently undergo surgery, radiation therapy, hormonal therapy, chemotherapy, or a combination of these for a cancer that may never become clinically significant. Until we can differentiate deadly from indolent cancers, highly sensitive screening tests will increase the risk of overtreatment.

Breast cancer has increased since the 1990s, mostly from detection of more cases of early-stage cancer and ductal carcinoma in situ

Breast cancer has increased in incidence since the 1990s, mostly from the detection of more early-stage cancer or ductal carcinoma in situ (DCIS). Rare before widespread screening, DCIS now accounts for 20% to 30% of all breast cancer diagnoses.^6,7 However, DCIS is not always a precursor to invasive cancer: untreated, it progresses to invasive disease in half of cases or fewer. Because DCIS is usually diagnosed only with mammography, its incidence has been steadily on the rise since screening became widespread.¹

Welch and Passow⁶ reviewed the available evidence and attempted to provide a range of estimates for three outcomes important to the mammography decision: breast cancer deaths avoided, false alarms, and overdiagnosis. For every 1,000 US women screened yearly for a decade starting at age 50, an estimated 0.3 to 3.2 avoided breast cancer death, 490 to 670 had at least one false alarm, and 3 to 14 were overdiagnosed and treated needlessly.

Esserman et al⁷ calculated that in women age 50 to 70, prevention of one breast cancer death would require that 838 women be screened for 6 years, leading to 5,866 screening visits, 535 recalls, 90 biopsies, and 24 cancers treated (18 invasive, 6 DCIS).

SCREENING EVERY YEAR VS EVERY 2 YEARS

Also controversial is whether screening mammography should be done annually or every 2 years. For women in their 50s, the American Cancer Society recommends mammography every year, the American College of Physicians and American Academy of Family Physicians recommend it every 1 to 2 years, and the USPSTF recommends it every 2 years.

A prospective analysis of 11,474 women with breast cancer and 922,624 controls⁸ found that performing mammography every 2 years instead of annually for women age 50 to 74 did not increase the risk of advanced-stage or large-size tumors regardless of breast density or hormone therapy use. But women undergoing annual mammography had a higher risk of false-positive results and biopsy recommendations.⁸ Women age 40 to 49 with extremely dense breasts were the only subgroup who derived additional benefit from annual screening, as they had a higher risk of advanced-stage cancer if they were screened every 2 years instead of yearly (odds ratio [OR] 1.89; 95% CI 1.06–3.39) and a higher risk of larger tumors (OR 2.39; 95% CI 1.37–4.18). However, the probability of a false-positive result in these younger women undergoing annual mammography was also very high at 65.5%.⁸

For most women in their 40s (other than those with extremely dense breasts) and 50s, biennial and annual mammography were associated with a similar risk of advanced-stage disease. Women with fatty breasts are at low risk of breast cancer regardless of other risk factors and did not appear to benefit from annual screening.⁸ The 12% to 15% of women in their 40s with extremely dense breasts (whose risk of breast cancer is similar to that in average-risk women in their 50s) should decide if the added benefit of annual screening is outweighed by the additional harms, including doubling the number of mammograms, as well as more false-positive results and breast biopsy recommendations.⁸

Mandelblatt et al⁹ statistically evaluated 20 screening strategies, ie, screening every year or every 2 years, and starting and stopping at various ages. On average, screening every 2 years was 81% as beneficial as annual screening but caused only about half as many false-positive results. Women age 50 through 69 who were screened every 2 years achieved a median 16.5% (range 15%–23%) reduction in breast cancer deaths compared with no screening. Initiating screening every 2 years at age 40 reduced the death rate by an additional 3% (range 1%–6%) compared with starting at age 50. Not surprisingly, starting screening at age 40 consumed more resources and yielded more false-positive results. After age 69, screening every 2 years yielded some additional mortality reduction in all models, but overdiagnosis increased most substantially at older ages, as the ratio of slow- to fast-growing tumors increases with age. The authors concluded that screening every 2 years achieves most of the benefit of annual screening with less harm.

FALSE-POSITIVE RESULTS AND ANXIETY

False-positive results on mammography can increase distress and anxiety about breast cancer and perceived breast cancer risk in some women.³ After 10 years of annual screening, more than half of women receive at least one false-positive recall, and 7% to 9% receive a false-positive biopsy recommendation. It is helpful for women to understand this risk when deciding whether to start mammographic screening.¹⁰

OUR VIEWS

There are two major issues to address in clinical practice regarding mammographic screening: at what age to start, and how often to screen. For years, women have been instructed to start annual mammographic screening at age 40, and such established patterns can be difficult to change.

Women need to be aware of the benefits and risks to make an informed decision

When deciding whether to have a mammogram at age 40, women should be aware of the full range of risks and benefits. Assessing a woman’s individual risk of breast cancer (based on family history and number and age of pregnancies) can be an important starting point for assessing the potential benefits and risks of screening.

Although a shared decision-making approach is intuitively appealing, it takes much more time than simply ordering a mammogram. Time constraints during a medical appointment may make it challenging to have a prolonged discussion about the pros and cons of screening. Patient education materials about the risks vs benefits of screening initiation may be useful, and because the decision does not usually need to be made urgently, women can be given the opportunity to consider the decision outside of the primary care appointment.

The issue of annual vs biennial screening presents an additional challenge, because women have come to expect annual screening. Studies show that the only subgroup of women who appear to benefit from annual screening are those in their 40s with dense breasts. Although breast cancer is rarer in younger women, when it does develop, it is often more aggressive, so offering annual screening to this subpopulation may make sense. For all other women, since there is no evidence that annual mammography offers clinical benefit over biennial screening, clinicians can be comfortable with offering screening every 2 years.

Future research must focus on developing better tools for differentiating women who are at higher vs lower risk for breast cancer and on developing methods to determine which DCIS cancers are more likely to be indolent and therefore amenable to watchful waiting.

In the interim, we must continue to identify women at high risk who will benefit from magnetic resonance imaging, genetic testing, and prophylactic medications, in accordance with USPSTF recommendations. Women with new breast symptoms or concerns should continue to undergo evaluation with diagnostic imaging, including mammography. However, for most women who are at average risk and have no symptoms, we must ensure that they are fully aware of the possible benefits and risks of screening mammography so that they can make an informed decision about when to start screening and how often to be screened.

National societies agree on the value of mammographic screening at age 50 through 69 (though the frequency is still debated), but there is no consensus about whether to screen at age 40 through 49, or age 70 and older. The US Preventive Services Task Force (USPSTF) recommends against routinely screening women age 40 through 49, while the American Academy of Family Physicians and the American College of Physicians recommend screening every 1 to 2 years for women in this age group. The American Cancer Society, the American Medical Association, the National Cancer Institute, the American College of Radiology, and the American Congress of Obstetricians and Gynecologists recommend yearly mammography starting at age 40.¹

See opposing commentary

Besides female sex, the major risk factor for breast cancer is increasing age. Thus, women in their 40s are at significantly lower risk of breast cancer than those in their 50s. As emerging evidence focuses on the potential harms and benefits from screening, we must question the practice of annual screening starting at age 40.

DOES MAMMOGRAPHIC SCREENING SAVE LIVES?

The main goal of screening for any type of cancer is to reduce the death rate. A 2014 meta-analysis of randomized controlled trials found a 15% to 20% relative decrease in the breast cancer mortality rate with screening mammography, approximately 15% for women in their 40s and 32% for women in their 60s.² Since the prevalence of breast cancer is lower in younger women, many more women in their 40s must be screened to prevent one breast cancer death. For women age 60 to 69, 377 must be screened to prevent one breast cancer death, whereas for women age 39 to 49 the number is 1,904.³

In view of potential harm, we question starting annual screening at age 40

Whether screening for breast cancer reduces the death rate has been questioned following the 2014 publication of 25-year follow-up data from the Canadian National Breast Screening Study.⁴ This randomized controlled trial of screening mammography and clinical breast examination, launched in 1980, involved 89,835 women and 5 years of screening. Women age 40 to 49 were randomly assigned to undergo either five annual mammographic screenings and annual clinical breast examinations or no mammography and a single clinical breast examination, followed by usual care in the community. Those age 50 to 59 received annual clinical breast examinations and were randomized to either mammography or no mammography.

During 25 years of follow-up, 3,250 women in the mammography group and 3,133 in the control group were diagnosed with breast cancer, and 500 and 505, respectively, died of breast cancer. No difference in mortality rate was found between the mammography and control groups (hazard ratio 0.99, 95% confidence interval 0.88–1.12), and the findings in both age cohorts were similar.⁴

Criticisms of this study include that it was performed using outdated imaging technology, and that a significant proportion of the control group also received mammography, although it is also possible that the mortality benefit from mammographic screening alone may not be as high as once predicted.

Reduction in breast cancer mortality is likely from a combination of screening mammography and better treatment. The number of women presenting with late-stage cancers has decreased in the past 3 decades, but only slightly; and most of the decrease has been in regional, node-positive disease, a stage that can now often be treated successfully (the expected 5-year survival rate is 85% in women age 40 or older).⁵ For women with estrogen receptor-positive tumors, the combination of hormonal therapy and adjuvant chemotherapy has reduced the death rate by half.⁶

It has been 50 years since a large randomized controlled trial of mammographic screening has been done in the United States. Thus, further study is needed to understand whether screening is less valuable now that better treatments are available.

DOES MAMMOGRAPHIC SCREENING REDUCE LATE-STAGE CANCERS?

To be effective, screening must detect disease at an earlier, more curable stage. Although screening mammography has substantially increased the number of early-stage breast cancers detected, it has only marginally decreased the rate of diagnosis of late-stage cancers.⁵

It has been 50 years since the last large randomized US trial of mammography

The National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) data⁵ show that between 1976 and 2008 screening mammography was associated with a doubling in early-stage breast cancer cases detected (from 112 to 234 cases per 100,000 women per year, an absolute increase of 122 cases per 100,000 per year). In contrast, late-stage cancer diagnoses decreased by 8% (from 102 to 94 cases per 100,000 women per year, or an absolute decrease of 8 per 100,000 women per year). Assuming a constant underlying disease burden, only 8 of the 122 early-stage cancers diagnosed would be expected to progress to advanced disease, suggesting that the rest would have never harmed these women—ie, they were overdiagnosed. The authors estimated that in 2008, breast cancer was overdiagnosed in more than 70,000 women, accounting for 31% of all diagnosed breast cancers.⁵

HARMS OF OVERDIAGNOSIS

Based on SEER data, Bleyer and Welch⁵ estimated that more than 1 million US women may have been overdiagnosed with breast cancer in the past 3 decades. Many women in this situation subsequently undergo surgery, radiation therapy, hormonal therapy, chemotherapy, or a combination of these for a cancer that may never become clinically significant. Until we can differentiate deadly from indolent cancers, highly sensitive screening tests will increase the risk of overtreatment.

Breast cancer has increased since the 1990s, mostly from detection of more cases of early-stage cancer and ductal carcinoma in situ

Breast cancer has increased in incidence since the 1990s, mostly from the detection of more early-stage cancer or ductal carcinoma in situ (DCIS). Rare before widespread screening, DCIS now accounts for 20% to 30% of all breast cancer diagnoses.^6,7 However, DCIS is not always a precursor to invasive cancer: untreated, it progresses to invasive disease in half of cases or fewer. Because DCIS is usually diagnosed only with mammography, its incidence has been steadily on the rise since screening became widespread.¹

Welch and Passow⁶ reviewed the available evidence and attempted to provide a range of estimates for three outcomes important to the mammography decision: breast cancer deaths avoided, false alarms, and overdiagnosis. For every 1,000 US women screened yearly for a decade starting at age 50, an estimated 0.3 to 3.2 avoided breast cancer death, 490 to 670 had at least one false alarm, and 3 to 14 were overdiagnosed and treated needlessly.

Esserman et al⁷ calculated that in women age 50 to 70, prevention of one breast cancer death would require that 838 women be screened for 6 years, leading to 5,866 screening visits, 535 recalls, 90 biopsies, and 24 cancers treated (18 invasive, 6 DCIS).

SCREENING EVERY YEAR VS EVERY 2 YEARS

Also controversial is whether screening mammography should be done annually or every 2 years. For women in their 50s, the American Cancer Society recommends mammography every year, the American College of Physicians and American Academy of Family Physicians recommend it every 1 to 2 years, and the USPSTF recommends it every 2 years.

A prospective analysis of 11,474 women with breast cancer and 922,624 controls⁸ found that performing mammography every 2 years instead of annually for women age 50 to 74 did not increase the risk of advanced-stage or large-size tumors regardless of breast density or hormone therapy use. But women undergoing annual mammography had a higher risk of false-positive results and biopsy recommendations.⁸ Women age 40 to 49 with extremely dense breasts were the only subgroup who derived additional benefit from annual screening, as they had a higher risk of advanced-stage cancer if they were screened every 2 years instead of yearly (odds ratio [OR] 1.89; 95% CI 1.06–3.39) and a higher risk of larger tumors (OR 2.39; 95% CI 1.37–4.18). However, the probability of a false-positive result in these younger women undergoing annual mammography was also very high at 65.5%.⁸

For most women in their 40s (other than those with extremely dense breasts) and 50s, biennial and annual mammography were associated with a similar risk of advanced-stage disease. Women with fatty breasts are at low risk of breast cancer regardless of other risk factors and did not appear to benefit from annual screening.⁸ The 12% to 15% of women in their 40s with extremely dense breasts (whose risk of breast cancer is similar to that in average-risk women in their 50s) should decide if the added benefit of annual screening is outweighed by the additional harms, including doubling the number of mammograms, as well as more false-positive results and breast biopsy recommendations.⁸

Mandelblatt et al⁹ statistically evaluated 20 screening strategies, ie, screening every year or every 2 years, and starting and stopping at various ages. On average, screening every 2 years was 81% as beneficial as annual screening but caused only about half as many false-positive results. Women age 50 through 69 who were screened every 2 years achieved a median 16.5% (range 15%–23%) reduction in breast cancer deaths compared with no screening. Initiating screening every 2 years at age 40 reduced the death rate by an additional 3% (range 1%–6%) compared with starting at age 50. Not surprisingly, starting screening at age 40 consumed more resources and yielded more false-positive results. After age 69, screening every 2 years yielded some additional mortality reduction in all models, but overdiagnosis increased most substantially at older ages, as the ratio of slow- to fast-growing tumors increases with age. The authors concluded that screening every 2 years achieves most of the benefit of annual screening with less harm.

FALSE-POSITIVE RESULTS AND ANXIETY

False-positive results on mammography can increase distress and anxiety about breast cancer and perceived breast cancer risk in some women.³ After 10 years of annual screening, more than half of women receive at least one false-positive recall, and 7% to 9% receive a false-positive biopsy recommendation. It is helpful for women to understand this risk when deciding whether to start mammographic screening.¹⁰

OUR VIEWS

There are two major issues to address in clinical practice regarding mammographic screening: at what age to start, and how often to screen. For years, women have been instructed to start annual mammographic screening at age 40, and such established patterns can be difficult to change.

Women need to be aware of the benefits and risks to make an informed decision

When deciding whether to have a mammogram at age 40, women should be aware of the full range of risks and benefits. Assessing a woman’s individual risk of breast cancer (based on family history and number and age of pregnancies) can be an important starting point for assessing the potential benefits and risks of screening.

Although a shared decision-making approach is intuitively appealing, it takes much more time than simply ordering a mammogram. Time constraints during a medical appointment may make it challenging to have a prolonged discussion about the pros and cons of screening. Patient education materials about the risks vs benefits of screening initiation may be useful, and because the decision does not usually need to be made urgently, women can be given the opportunity to consider the decision outside of the primary care appointment.

The issue of annual vs biennial screening presents an additional challenge, because women have come to expect annual screening. Studies show that the only subgroup of women who appear to benefit from annual screening are those in their 40s with dense breasts. Although breast cancer is rarer in younger women, when it does develop, it is often more aggressive, so offering annual screening to this subpopulation may make sense. For all other women, since there is no evidence that annual mammography offers clinical benefit over biennial screening, clinicians can be comfortable with offering screening every 2 years.

Future research must focus on developing better tools for differentiating women who are at higher vs lower risk for breast cancer and on developing methods to determine which DCIS cancers are more likely to be indolent and therefore amenable to watchful waiting.

In the interim, we must continue to identify women at high risk who will benefit from magnetic resonance imaging, genetic testing, and prophylactic medications, in accordance with USPSTF recommendations. Women with new breast symptoms or concerns should continue to undergo evaluation with diagnostic imaging, including mammography. However, for most women who are at average risk and have no symptoms, we must ensure that they are fully aware of the possible benefits and risks of screening mammography so that they can make an informed decision about when to start screening and how often to be screened.

Screening mammography is not a perfect test, but it still plays an important role for women even in their 40s, when the incidence of breast cancer is low but the risk of a tumor being aggressive is especially high.

See related counterpoint

SCREENING DETECTS CANCER EARLY

The goal of screening mammography is to reduce breast cancer deaths by detecting cancers early, when treatment is more effective and less harmful.

Mammography detects tumors when they are smaller: the median size of breast cancers found with high-quality, two-view screening mammography is 1.0 to 1.5 cm, whereas cancers found by palpation are 2.0 to 2.5 cm.¹ In general, tumors found when they are smaller require less treatment, and patients are more likely to survive.

Moreover, about 10% of invasive cancers smaller than 1 cm have spread to lymph nodes at the time of detection, compared with 35% of those 2 cm in size and 60% of those 4 cm or larger. Women who have a positive lymph node at the time of diagnosis usually undergo more intensive treatment with chemotherapy and more radical surgery than those who do not. The 5-year disease-free survival rate is more than 98% for breast cancer with a tumor smaller than 2 cm that has not spread to lymph nodes (stage I), compared with 86% for stage II disease (tumors 2.1–5 cm or one to three positive axillary lymph nodes).²

The median size of breast cancers found by mammography is 1.0–1.5 cm; by palpation, 2.0–2.5 cm

Treating breast cancer early is also less expensive. In a study of women enrolled in a health maintenance organization in Pennsylvania, 14% of those not screened presented with advanced breast cancer (stage III or IV) compared with 2% who had been screened. The cumulative cost of treating advanced breast cancer was two to three times that of treating early breast cancer (stage 0 or I), not accounting for time lost away from work and family, in addition to pain and suffering.³

SCREENING SAVES LIVES

Multiple prospective, randomized controlled trials have been conducted to assess whether inviting women between ages 40 and 74 to undergo screening mammography reduces the rate of death from breast cancer.^4,5 Such trials tend to underestimate the effect of screening because not all women invited to be screened actually are screened, and some in the control group may undergo screening on their own.⁶

The Canadian National Breast Screening Study (NBSS) had additional problems that underestimated the benefits of screening. The quality of mammography came under question, and an issue with randomization became evident after the first round of screening, as  the group invited to be screened had an excess of women presenting with palpable lumps and advanced breast cancer.^6–8 Despite these issues, a meta-analysis of randomized controlled trials of screening mammography, including the NBSS data, found a 15% reduction in deaths.⁹ When the NBSS data were excluded, the reduction was 24%.¹⁰

In 2009, the United States Preventive Services Task Force (USPSTF)¹¹ recommended against mammographic screening for women ages 40 to 49. Using results from trials including the NBSS, they estimated that the number of women needed to be invited to screening to prevent one breast cancer death was:

• 1,904 for ages 39 to 49
• 1,339 for ages 50 to 59
• 377 for ages 60 to 69.

But if the NBSS study were excluded, these results would be 950, 670, and 377, respectively.⁶

In a review on screening mammography, Feig¹² points out that the USPSTF selected the number of women invited to be screened rather than the number that were actually screened to measure the absolute benefit of screening.

Hendrick and Helvie¹³ reported that the number of women who needed to be screened to prevent one cancer death was:

• 746 for ages 40 to 49
• 351 for ages 50 to 59
• 253 for ages 60 to 69.

The benefit of screening, if analyzed by number of life years gained rather than number of deaths prevented, is even more favorable to younger women with longer life expectancy. The number needed to be screened per life year gained is:

• 28 at ages 40 to 49
• 17 at ages 50 to 59
• 16 at ages 60 to 69.¹²

These data provide additional support for screening women starting at age 40.

Observational studies, which provide a better measure of effectiveness because only women who actually undergo routine mammography are compared with those who do not, also support this conclusion. An observational study in Sweden with 20 years of follow-up found that women of all ages who participated in screening had a 44% lower risk of death from breast cancer than with those who were not screened; for women in their 40s, the risk reduction was 48%.¹⁴ Similarly, an observational study conducted in British Columbia¹⁵ found a 40% decrease in deaths in women screened annually between ages 40 and 79, and a 39% decrease in deaths in women first screened between ages 40 and 49.

LOW RATE OF FALSE-POSITIVE RESULTS

Like many screening programs, screening mammography does not benefit all women equally.

Only about 1% of the women screened underwent an unnecessary biopsy

False-positive results occur, for which women need additional imaging or a biopsy for findings that turn out not to be cancer. But the false-positive rate is not high: for every 1,000 women screened in the United States, 80 to 100 (10% or less) are recalled for additional evaluation, 15 (1.5%) undergo biopsy, and 2 to 5 have a cancer, so only about 1% of the women screened underwent an unnecessary biopsy.¹⁶

False-positive test results can provoke unnecessary anxiety, but evidence indicates that this tends to be a temporary effect, and even women who had a false-positive result tend to support mammography. In a report by Lerman et al,¹⁷ when mood was assessed 3 months after mammography, worry was reported by 26% of women who had had a false-positive report, compared with 9% of women who had had a normal mammogram. Another report addressing the consequences of false-positive mammograms found that although short-term anxiety increased, long-term anxiety did not.¹⁸­ In a random telephone survey, 98% of adults who reported having had a false-positive cancer screening result stated that they were nevertheless glad that they had undergone screening.¹⁹

OVERDIAGNOSIS OCCURS BUT IS LIKELY UNCOMMON

Overdiagnosis of breast cancer is a possible drawback of screening mammography. Cancers may be detected that would not have become clinically apparent in a person’s lifetime²⁰ or have affected ultimate prognosis,¹⁸ and so would not have needed to be treated.

Overdiagnosis from screening mammography usually refers to finding ductal carcinoma in situ (DCIS) on breast biopsy. Because no randomized controlled study has been done in which breast cancer was diagnosed and not treated, evidence of the danger from DCIS comes from retrospective reviews of 130 cases in which excised tissue initially interpreted as benign was actually cancerous. Over 10 to 30 years, 11% to 60% of these patients developed invasive breast cancer in the same quadrant from which tissue had been excised.²¹ This rate of cancer development could lead to underestimation of the invasive potential of DCIS because the patients studied all had low-grade DCIS; further, some of the baseline biopsies involved complete removal of the tumor, thereby preventing the development or progression of cancer.

All DCIS is not the same. An ongoing trial²² found a 5-year recurrence rate of 6.1% after surgery for low-grade or intermediate-grade DCIS, and 15% after surgery for high-grade DCIS. Swedish trials²³ have shown that most women who die of “early” breast cancer have high-grade DCIS. These findings suggest that although screening mammography may result in overdiagnosis and overtreatment of low-grade DCIS, high-grade DCIS can be lethal and should be treated. Thus, overdiagnosis likely represents a small fraction of all breast cancers.

Most important, it is not yet possible to accurately predict the biologic behavior of an individual tumor. Current clinical practice is to treat patients with DCIS similar to the way we treat patients with early-stage breast cancer, as we cannot determine which types of DCIS may remain indolent and which ones may become invasive.

HOW FREQUENTLY SHOULD YOUNGER WOMEN BE SCREENED?

The frequency of screening mammography has been another area of controversy, but we believe that annual screening offers the greatest benefit, especially for younger women.

Tumors in younger women tend to grow and spread more quickly

The optimum screening frequency depends on how fast breast cancer grows and spreads. Data suggest that tumors in younger women tend to be biologically aggressive and grow and spread more quickly, making the benefit of yearly mammography more dramatic for younger women. A model­ based on data from Swedish studies^24–26 predicted that the mortality reduction from breast cancer in women ages 40 to 49 would be 36% with annual screening, 18% with screening every 2 years, and 4% with screening every 3 years. For women in their 50s, the model estimated a reduction of 46% for yearly mammography, and 39% and 34% for screening every 2 or 3 years, respectively.⁶

In a prospective cohort study of the Breast Cancer Surveillance Consortium,²⁷ in women ages 40 to 49 with extremely dense breasts, screening every 2 years was associated with a higher risk of advanced-stage disease (IIb or higher) and large tumors (> 2 cm) than with annual screening. For women ages 50 to 74, screening every 2 years vs every year did not increase the odds of advanced-stage or larger tumors.

AN INFORMED DECISION

In agreement with the current recommendations from the American Cancer Society, the American College of Radiology, and the American Congress of Obstetricians and Gynecologists, we support starting breast cancer screening with mammography at age 40.

Not all cancers are visible on mammography (false negatives), as they may be masked by mammographically dense breast tissue. Women should be informed of the importance of seeking medical attention for breast symptoms, even if mammography is normal. We need to inform women of the benefits and risks of screening mammography, including the risk of false-positive results that could lead to additional imaging and anxiety, and the uncertainties related to the potential for overdiagnosis and overtreatment. This information, offered in an easily understandable format, can help the patient make an informed decision regarding screening mammography, based on her values and preferences.

Screening mammography is not a perfect test, but it still plays an important role for women even in their 40s, when the incidence of breast cancer is low but the risk of a tumor being aggressive is especially high.

See related counterpoint

SCREENING DETECTS CANCER EARLY

The goal of screening mammography is to reduce breast cancer deaths by detecting cancers early, when treatment is more effective and less harmful.

Mammography detects tumors when they are smaller: the median size of breast cancers found with high-quality, two-view screening mammography is 1.0 to 1.5 cm, whereas cancers found by palpation are 2.0 to 2.5 cm.¹ In general, tumors found when they are smaller require less treatment, and patients are more likely to survive.

Moreover, about 10% of invasive cancers smaller than 1 cm have spread to lymph nodes at the time of detection, compared with 35% of those 2 cm in size and 60% of those 4 cm or larger. Women who have a positive lymph node at the time of diagnosis usually undergo more intensive treatment with chemotherapy and more radical surgery than those who do not. The 5-year disease-free survival rate is more than 98% for breast cancer with a tumor smaller than 2 cm that has not spread to lymph nodes (stage I), compared with 86% for stage II disease (tumors 2.1–5 cm or one to three positive axillary lymph nodes).²

The median size of breast cancers found by mammography is 1.0–1.5 cm; by palpation, 2.0–2.5 cm

Treating breast cancer early is also less expensive. In a study of women enrolled in a health maintenance organization in Pennsylvania, 14% of those not screened presented with advanced breast cancer (stage III or IV) compared with 2% who had been screened. The cumulative cost of treating advanced breast cancer was two to three times that of treating early breast cancer (stage 0 or I), not accounting for time lost away from work and family, in addition to pain and suffering.³

SCREENING SAVES LIVES

Multiple prospective, randomized controlled trials have been conducted to assess whether inviting women between ages 40 and 74 to undergo screening mammography reduces the rate of death from breast cancer.^4,5 Such trials tend to underestimate the effect of screening because not all women invited to be screened actually are screened, and some in the control group may undergo screening on their own.⁶

The Canadian National Breast Screening Study (NBSS) had additional problems that underestimated the benefits of screening. The quality of mammography came under question, and an issue with randomization became evident after the first round of screening, as  the group invited to be screened had an excess of women presenting with palpable lumps and advanced breast cancer.^6–8 Despite these issues, a meta-analysis of randomized controlled trials of screening mammography, including the NBSS data, found a 15% reduction in deaths.⁹ When the NBSS data were excluded, the reduction was 24%.¹⁰

In 2009, the United States Preventive Services Task Force (USPSTF)¹¹ recommended against mammographic screening for women ages 40 to 49. Using results from trials including the NBSS, they estimated that the number of women needed to be invited to screening to prevent one breast cancer death was:

• 1,904 for ages 39 to 49
• 1,339 for ages 50 to 59
• 377 for ages 60 to 69.

But if the NBSS study were excluded, these results would be 950, 670, and 377, respectively.⁶

In a review on screening mammography, Feig¹² points out that the USPSTF selected the number of women invited to be screened rather than the number that were actually screened to measure the absolute benefit of screening.

Hendrick and Helvie¹³ reported that the number of women who needed to be screened to prevent one cancer death was:

• 746 for ages 40 to 49
• 351 for ages 50 to 59
• 253 for ages 60 to 69.

The benefit of screening, if analyzed by number of life years gained rather than number of deaths prevented, is even more favorable to younger women with longer life expectancy. The number needed to be screened per life year gained is:

• 28 at ages 40 to 49
• 17 at ages 50 to 59
• 16 at ages 60 to 69.¹²

These data provide additional support for screening women starting at age 40.

Observational studies, which provide a better measure of effectiveness because only women who actually undergo routine mammography are compared with those who do not, also support this conclusion. An observational study in Sweden with 20 years of follow-up found that women of all ages who participated in screening had a 44% lower risk of death from breast cancer than with those who were not screened; for women in their 40s, the risk reduction was 48%.¹⁴ Similarly, an observational study conducted in British Columbia¹⁵ found a 40% decrease in deaths in women screened annually between ages 40 and 79, and a 39% decrease in deaths in women first screened between ages 40 and 49.

LOW RATE OF FALSE-POSITIVE RESULTS

Like many screening programs, screening mammography does not benefit all women equally.

Only about 1% of the women screened underwent an unnecessary biopsy

False-positive results occur, for which women need additional imaging or a biopsy for findings that turn out not to be cancer. But the false-positive rate is not high: for every 1,000 women screened in the United States, 80 to 100 (10% or less) are recalled for additional evaluation, 15 (1.5%) undergo biopsy, and 2 to 5 have a cancer, so only about 1% of the women screened underwent an unnecessary biopsy.¹⁶

False-positive test results can provoke unnecessary anxiety, but evidence indicates that this tends to be a temporary effect, and even women who had a false-positive result tend to support mammography. In a report by Lerman et al,¹⁷ when mood was assessed 3 months after mammography, worry was reported by 26% of women who had had a false-positive report, compared with 9% of women who had had a normal mammogram. Another report addressing the consequences of false-positive mammograms found that although short-term anxiety increased, long-term anxiety did not.¹⁸­ In a random telephone survey, 98% of adults who reported having had a false-positive cancer screening result stated that they were nevertheless glad that they had undergone screening.¹⁹

OVERDIAGNOSIS OCCURS BUT IS LIKELY UNCOMMON

Overdiagnosis of breast cancer is a possible drawback of screening mammography. Cancers may be detected that would not have become clinically apparent in a person’s lifetime²⁰ or have affected ultimate prognosis,¹⁸ and so would not have needed to be treated.

Overdiagnosis from screening mammography usually refers to finding ductal carcinoma in situ (DCIS) on breast biopsy. Because no randomized controlled study has been done in which breast cancer was diagnosed and not treated, evidence of the danger from DCIS comes from retrospective reviews of 130 cases in which excised tissue initially interpreted as benign was actually cancerous. Over 10 to 30 years, 11% to 60% of these patients developed invasive breast cancer in the same quadrant from which tissue had been excised.²¹ This rate of cancer development could lead to underestimation of the invasive potential of DCIS because the patients studied all had low-grade DCIS; further, some of the baseline biopsies involved complete removal of the tumor, thereby preventing the development or progression of cancer.

All DCIS is not the same. An ongoing trial²² found a 5-year recurrence rate of 6.1% after surgery for low-grade or intermediate-grade DCIS, and 15% after surgery for high-grade DCIS. Swedish trials²³ have shown that most women who die of “early” breast cancer have high-grade DCIS. These findings suggest that although screening mammography may result in overdiagnosis and overtreatment of low-grade DCIS, high-grade DCIS can be lethal and should be treated. Thus, overdiagnosis likely represents a small fraction of all breast cancers.

Most important, it is not yet possible to accurately predict the biologic behavior of an individual tumor. Current clinical practice is to treat patients with DCIS similar to the way we treat patients with early-stage breast cancer, as we cannot determine which types of DCIS may remain indolent and which ones may become invasive.

HOW FREQUENTLY SHOULD YOUNGER WOMEN BE SCREENED?

The frequency of screening mammography has been another area of controversy, but we believe that annual screening offers the greatest benefit, especially for younger women.

Tumors in younger women tend to grow and spread more quickly

The optimum screening frequency depends on how fast breast cancer grows and spreads. Data suggest that tumors in younger women tend to be biologically aggressive and grow and spread more quickly, making the benefit of yearly mammography more dramatic for younger women. A model­ based on data from Swedish studies^24–26 predicted that the mortality reduction from breast cancer in women ages 40 to 49 would be 36% with annual screening, 18% with screening every 2 years, and 4% with screening every 3 years. For women in their 50s, the model estimated a reduction of 46% for yearly mammography, and 39% and 34% for screening every 2 or 3 years, respectively.⁶

In a prospective cohort study of the Breast Cancer Surveillance Consortium,²⁷ in women ages 40 to 49 with extremely dense breasts, screening every 2 years was associated with a higher risk of advanced-stage disease (IIb or higher) and large tumors (> 2 cm) than with annual screening. For women ages 50 to 74, screening every 2 years vs every year did not increase the odds of advanced-stage or larger tumors.

AN INFORMED DECISION

In agreement with the current recommendations from the American Cancer Society, the American College of Radiology, and the American Congress of Obstetricians and Gynecologists, we support starting breast cancer screening with mammography at age 40.

Not all cancers are visible on mammography (false negatives), as they may be masked by mammographically dense breast tissue. Women should be informed of the importance of seeking medical attention for breast symptoms, even if mammography is normal. We need to inform women of the benefits and risks of screening mammography, including the risk of false-positive results that could lead to additional imaging and anxiety, and the uncertainties related to the potential for overdiagnosis and overtreatment. This information, offered in an easily understandable format, can help the patient make an informed decision regarding screening mammography, based on her values and preferences.

Screening mammography is not a perfect test, but it still plays an important role for women even in their 40s, when the incidence of breast cancer is low but the risk of a tumor being aggressive is especially high.

See related counterpoint

SCREENING DETECTS CANCER EARLY

The goal of screening mammography is to reduce breast cancer deaths by detecting cancers early, when treatment is more effective and less harmful.

Mammography detects tumors when they are smaller: the median size of breast cancers found with high-quality, two-view screening mammography is 1.0 to 1.5 cm, whereas cancers found by palpation are 2.0 to 2.5 cm.¹ In general, tumors found when they are smaller require less treatment, and patients are more likely to survive.

Moreover, about 10% of invasive cancers smaller than 1 cm have spread to lymph nodes at the time of detection, compared with 35% of those 2 cm in size and 60% of those 4 cm or larger. Women who have a positive lymph node at the time of diagnosis usually undergo more intensive treatment with chemotherapy and more radical surgery than those who do not. The 5-year disease-free survival rate is more than 98% for breast cancer with a tumor smaller than 2 cm that has not spread to lymph nodes (stage I), compared with 86% for stage II disease (tumors 2.1–5 cm or one to three positive axillary lymph nodes).²

The median size of breast cancers found by mammography is 1.0–1.5 cm; by palpation, 2.0–2.5 cm

Treating breast cancer early is also less expensive. In a study of women enrolled in a health maintenance organization in Pennsylvania, 14% of those not screened presented with advanced breast cancer (stage III or IV) compared with 2% who had been screened. The cumulative cost of treating advanced breast cancer was two to three times that of treating early breast cancer (stage 0 or I), not accounting for time lost away from work and family, in addition to pain and suffering.³

SCREENING SAVES LIVES

Multiple prospective, randomized controlled trials have been conducted to assess whether inviting women between ages 40 and 74 to undergo screening mammography reduces the rate of death from breast cancer.^4,5 Such trials tend to underestimate the effect of screening because not all women invited to be screened actually are screened, and some in the control group may undergo screening on their own.⁶

The Canadian National Breast Screening Study (NBSS) had additional problems that underestimated the benefits of screening. The quality of mammography came under question, and an issue with randomization became evident after the first round of screening, as  the group invited to be screened had an excess of women presenting with palpable lumps and advanced breast cancer.^6–8 Despite these issues, a meta-analysis of randomized controlled trials of screening mammography, including the NBSS data, found a 15% reduction in deaths.⁹ When the NBSS data were excluded, the reduction was 24%.¹⁰

In 2009, the United States Preventive Services Task Force (USPSTF)¹¹ recommended against mammographic screening for women ages 40 to 49. Using results from trials including the NBSS, they estimated that the number of women needed to be invited to screening to prevent one breast cancer death was:

• 1,904 for ages 39 to 49
• 1,339 for ages 50 to 59
• 377 for ages 60 to 69.

But if the NBSS study were excluded, these results would be 950, 670, and 377, respectively.⁶

In a review on screening mammography, Feig¹² points out that the USPSTF selected the number of women invited to be screened rather than the number that were actually screened to measure the absolute benefit of screening.

Hendrick and Helvie¹³ reported that the number of women who needed to be screened to prevent one cancer death was:

• 746 for ages 40 to 49
• 351 for ages 50 to 59
• 253 for ages 60 to 69.

The benefit of screening, if analyzed by number of life years gained rather than number of deaths prevented, is even more favorable to younger women with longer life expectancy. The number needed to be screened per life year gained is:

• 28 at ages 40 to 49
• 17 at ages 50 to 59
• 16 at ages 60 to 69.¹²

These data provide additional support for screening women starting at age 40.

Observational studies, which provide a better measure of effectiveness because only women who actually undergo routine mammography are compared with those who do not, also support this conclusion. An observational study in Sweden with 20 years of follow-up found that women of all ages who participated in screening had a 44% lower risk of death from breast cancer than with those who were not screened; for women in their 40s, the risk reduction was 48%.¹⁴ Similarly, an observational study conducted in British Columbia¹⁵ found a 40% decrease in deaths in women screened annually between ages 40 and 79, and a 39% decrease in deaths in women first screened between ages 40 and 49.

LOW RATE OF FALSE-POSITIVE RESULTS

Like many screening programs, screening mammography does not benefit all women equally.

Only about 1% of the women screened underwent an unnecessary biopsy

False-positive results occur, for which women need additional imaging or a biopsy for findings that turn out not to be cancer. But the false-positive rate is not high: for every 1,000 women screened in the United States, 80 to 100 (10% or less) are recalled for additional evaluation, 15 (1.5%) undergo biopsy, and 2 to 5 have a cancer, so only about 1% of the women screened underwent an unnecessary biopsy.¹⁶

False-positive test results can provoke unnecessary anxiety, but evidence indicates that this tends to be a temporary effect, and even women who had a false-positive result tend to support mammography. In a report by Lerman et al,¹⁷ when mood was assessed 3 months after mammography, worry was reported by 26% of women who had had a false-positive report, compared with 9% of women who had had a normal mammogram. Another report addressing the consequences of false-positive mammograms found that although short-term anxiety increased, long-term anxiety did not.¹⁸­ In a random telephone survey, 98% of adults who reported having had a false-positive cancer screening result stated that they were nevertheless glad that they had undergone screening.¹⁹

OVERDIAGNOSIS OCCURS BUT IS LIKELY UNCOMMON

Overdiagnosis of breast cancer is a possible drawback of screening mammography. Cancers may be detected that would not have become clinically apparent in a person’s lifetime²⁰ or have affected ultimate prognosis,¹⁸ and so would not have needed to be treated.

Overdiagnosis from screening mammography usually refers to finding ductal carcinoma in situ (DCIS) on breast biopsy. Because no randomized controlled study has been done in which breast cancer was diagnosed and not treated, evidence of the danger from DCIS comes from retrospective reviews of 130 cases in which excised tissue initially interpreted as benign was actually cancerous. Over 10 to 30 years, 11% to 60% of these patients developed invasive breast cancer in the same quadrant from which tissue had been excised.²¹ This rate of cancer development could lead to underestimation of the invasive potential of DCIS because the patients studied all had low-grade DCIS; further, some of the baseline biopsies involved complete removal of the tumor, thereby preventing the development or progression of cancer.

All DCIS is not the same. An ongoing trial²² found a 5-year recurrence rate of 6.1% after surgery for low-grade or intermediate-grade DCIS, and 15% after surgery for high-grade DCIS. Swedish trials²³ have shown that most women who die of “early” breast cancer have high-grade DCIS. These findings suggest that although screening mammography may result in overdiagnosis and overtreatment of low-grade DCIS, high-grade DCIS can be lethal and should be treated. Thus, overdiagnosis likely represents a small fraction of all breast cancers.

Most important, it is not yet possible to accurately predict the biologic behavior of an individual tumor. Current clinical practice is to treat patients with DCIS similar to the way we treat patients with early-stage breast cancer, as we cannot determine which types of DCIS may remain indolent and which ones may become invasive.

HOW FREQUENTLY SHOULD YOUNGER WOMEN BE SCREENED?

The frequency of screening mammography has been another area of controversy, but we believe that annual screening offers the greatest benefit, especially for younger women.

Tumors in younger women tend to grow and spread more quickly

The optimum screening frequency depends on how fast breast cancer grows and spreads. Data suggest that tumors in younger women tend to be biologically aggressive and grow and spread more quickly, making the benefit of yearly mammography more dramatic for younger women. A model­ based on data from Swedish studies^24–26 predicted that the mortality reduction from breast cancer in women ages 40 to 49 would be 36% with annual screening, 18% with screening every 2 years, and 4% with screening every 3 years. For women in their 50s, the model estimated a reduction of 46% for yearly mammography, and 39% and 34% for screening every 2 or 3 years, respectively.⁶

In a prospective cohort study of the Breast Cancer Surveillance Consortium,²⁷ in women ages 40 to 49 with extremely dense breasts, screening every 2 years was associated with a higher risk of advanced-stage disease (IIb or higher) and large tumors (> 2 cm) than with annual screening. For women ages 50 to 74, screening every 2 years vs every year did not increase the odds of advanced-stage or larger tumors.

AN INFORMED DECISION

In agreement with the current recommendations from the American Cancer Society, the American College of Radiology, and the American Congress of Obstetricians and Gynecologists, we support starting breast cancer screening with mammography at age 40.

Not all cancers are visible on mammography (false negatives), as they may be masked by mammographically dense breast tissue. Women should be informed of the importance of seeking medical attention for breast symptoms, even if mammography is normal. We need to inform women of the benefits and risks of screening mammography, including the risk of false-positive results that could lead to additional imaging and anxiety, and the uncertainties related to the potential for overdiagnosis and overtreatment. This information, offered in an easily understandable format, can help the patient make an informed decision regarding screening mammography, based on her values and preferences.