Colon Cancer

TOPLINE:

More than 1 in 8 colorectal cancer (CRC) cases among veterans occur outside the standard screening age of 50-75 years or those with high-risk personal or family history. High-risk patients face > 6 times the risk for CRC compared with average-risk patients aged 50-75 years who are up to date with screening, while Black patients have > 50% higher risk compared with White patients.

METHODOLOGY:

• Researchers conducted a case-control analysis using Veterans Health Administration (VHA) Corporate Data Warehouse data from 2012-2018 at 2 sites: Veterans Affairs (VA) New York Harbor Health Care System and VA Puget Sound Health Care System.

• Participants included 3714 cases among veterans with CRC matched to 14,856 controls (4:1), with matching on age (± 3 years), sex, and facility site; each control was used once.

• Screening categories included 5 groups by age (50-75 years vs < 50 years or > 75 years), screening up-to-date status, and high-risk status (inflammatory bowel disease, hereditary cancer syndromes, or family history).

• CRC screening was considered up to date if US Preventive Services Task Force-recommended tests were completed on time (colonoscopy ≤ 10 years; guaiac-based fecal occult blood test or fecal immunochemical test ≤ 1 year).

TAKEAWAY:

• Compared with category 1 (age 50-75 years and up-to-date with screening), CRC was associated with category 4 (age < 50 years or > 75 years and not up to date) (odds ratio [OR], 1.40; 95% CI, 1.11-1.78), and category 5 (high risk) (OR, 6.23; 95% CI, 5.06-7.66).

• Race and comorbidity associations included higher CRC risk for Black vs White patients (OR, 1.54; 95% CI, 1.37-1.73), and higher CRC risk with diabetes (OR, 1.65; 95% CI, 1.51-1.81) and alcohol use disorder (OR, 1.53; 95% CI, 1.35-1.73).

• Among 3714 CRC cases, 71.1% occurred in individuals aged 50-75 years not up to date with screening.

• A total of 12.5% of CRC cases occurred in people outside age 50-75 or with high-risk personal or family history, suggesting that conventional screening-adherence metrics may miss a clinically relevant minority.

IN PRACTICE:

“The conventional measure of CRC screening, focused on average-risk individuals aged 50 to 75, does not reflect screening status in an important minority of CRC patients," the authors wrote.

SOURCE:

The study was led by researchers at NYU Grossman School of Medicine and Veterans Affairs New York Harbor Health Care System, and published online July 9, 2026 in Medicine.

LIMITATIONS:

The study population consisted predominantly of male veterans (97.1%), who tend to be older and have more comorbidities compared with the US population, which may limit the generalizability of findings to other populations. Researchers defined screening status cross-sectionally relative to a single point in time rather than assessing longitudinal screening adherence, which may not fully capture the consistency of screening over time that is likely important for defining CRC risk. Veterans may receive screening at non-VA medical facilities, potentially leading to incomplete documentation of screening status and important covariates such as race, ethnicity, and comorbidities. The possibility of residual confounding cannot be excluded despite adjustment for multiple risk factors in the analysis.

DISCLOSURES:

This study received support from NIH grant K08 CA230162 and the AGA Caroline Craig Augustyn & Damian Augustyn Award in Digestive Cancer, both awarded to Peter S. Liang. Liang disclosed receiving research support from Freenome and serving on the advisory boards for Guardant Health and Natera. The remaining authors reported no funding or conflicts of interest to disclose.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

TOPLINE:

More than 1 in 8 colorectal cancer (CRC) cases among veterans occur outside the standard screening age of 50-75 years or those with high-risk personal or family history. High-risk patients face > 6 times the risk for CRC compared with average-risk patients aged 50-75 years who are up to date with screening, while Black patients have > 50% higher risk compared with White patients.

METHODOLOGY:

• Researchers conducted a case-control analysis using Veterans Health Administration (VHA) Corporate Data Warehouse data from 2012-2018 at 2 sites: Veterans Affairs (VA) New York Harbor Health Care System and VA Puget Sound Health Care System.

• Participants included 3714 cases among veterans with CRC matched to 14,856 controls (4:1), with matching on age (± 3 years), sex, and facility site; each control was used once.

• Screening categories included 5 groups by age (50-75 years vs < 50 years or > 75 years), screening up-to-date status, and high-risk status (inflammatory bowel disease, hereditary cancer syndromes, or family history).

• CRC screening was considered up to date if US Preventive Services Task Force-recommended tests were completed on time (colonoscopy ≤ 10 years; guaiac-based fecal occult blood test or fecal immunochemical test ≤ 1 year).

TAKEAWAY:

• Compared with category 1 (age 50-75 years and up-to-date with screening), CRC was associated with category 4 (age < 50 years or > 75 years and not up to date) (odds ratio [OR], 1.40; 95% CI, 1.11-1.78), and category 5 (high risk) (OR, 6.23; 95% CI, 5.06-7.66).

• Race and comorbidity associations included higher CRC risk for Black vs White patients (OR, 1.54; 95% CI, 1.37-1.73), and higher CRC risk with diabetes (OR, 1.65; 95% CI, 1.51-1.81) and alcohol use disorder (OR, 1.53; 95% CI, 1.35-1.73).

• Among 3714 CRC cases, 71.1% occurred in individuals aged 50-75 years not up to date with screening.

• A total of 12.5% of CRC cases occurred in people outside age 50-75 or with high-risk personal or family history, suggesting that conventional screening-adherence metrics may miss a clinically relevant minority.

IN PRACTICE:

“The conventional measure of CRC screening, focused on average-risk individuals aged 50 to 75, does not reflect screening status in an important minority of CRC patients," the authors wrote.

SOURCE:

The study was led by researchers at NYU Grossman School of Medicine and Veterans Affairs New York Harbor Health Care System, and published online July 9, 2026 in Medicine.

LIMITATIONS:

The study population consisted predominantly of male veterans (97.1%), who tend to be older and have more comorbidities compared with the US population, which may limit the generalizability of findings to other populations. Researchers defined screening status cross-sectionally relative to a single point in time rather than assessing longitudinal screening adherence, which may not fully capture the consistency of screening over time that is likely important for defining CRC risk. Veterans may receive screening at non-VA medical facilities, potentially leading to incomplete documentation of screening status and important covariates such as race, ethnicity, and comorbidities. The possibility of residual confounding cannot be excluded despite adjustment for multiple risk factors in the analysis.

DISCLOSURES:

This study received support from NIH grant K08 CA230162 and the AGA Caroline Craig Augustyn & Damian Augustyn Award in Digestive Cancer, both awarded to Peter S. Liang. Liang disclosed receiving research support from Freenome and serving on the advisory boards for Guardant Health and Natera. The remaining authors reported no funding or conflicts of interest to disclose.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

TOPLINE:

More than 1 in 8 colorectal cancer (CRC) cases among veterans occur outside the standard screening age of 50-75 years or those with high-risk personal or family history. High-risk patients face > 6 times the risk for CRC compared with average-risk patients aged 50-75 years who are up to date with screening, while Black patients have > 50% higher risk compared with White patients.

METHODOLOGY:

• Researchers conducted a case-control analysis using Veterans Health Administration (VHA) Corporate Data Warehouse data from 2012-2018 at 2 sites: Veterans Affairs (VA) New York Harbor Health Care System and VA Puget Sound Health Care System.

• Participants included 3714 cases among veterans with CRC matched to 14,856 controls (4:1), with matching on age (± 3 years), sex, and facility site; each control was used once.

• Screening categories included 5 groups by age (50-75 years vs < 50 years or > 75 years), screening up-to-date status, and high-risk status (inflammatory bowel disease, hereditary cancer syndromes, or family history).

• CRC screening was considered up to date if US Preventive Services Task Force-recommended tests were completed on time (colonoscopy ≤ 10 years; guaiac-based fecal occult blood test or fecal immunochemical test ≤ 1 year).

TAKEAWAY:

• Compared with category 1 (age 50-75 years and up-to-date with screening), CRC was associated with category 4 (age < 50 years or > 75 years and not up to date) (odds ratio [OR], 1.40; 95% CI, 1.11-1.78), and category 5 (high risk) (OR, 6.23; 95% CI, 5.06-7.66).

• Race and comorbidity associations included higher CRC risk for Black vs White patients (OR, 1.54; 95% CI, 1.37-1.73), and higher CRC risk with diabetes (OR, 1.65; 95% CI, 1.51-1.81) and alcohol use disorder (OR, 1.53; 95% CI, 1.35-1.73).

• Among 3714 CRC cases, 71.1% occurred in individuals aged 50-75 years not up to date with screening.

• A total of 12.5% of CRC cases occurred in people outside age 50-75 or with high-risk personal or family history, suggesting that conventional screening-adherence metrics may miss a clinically relevant minority.

IN PRACTICE:

“The conventional measure of CRC screening, focused on average-risk individuals aged 50 to 75, does not reflect screening status in an important minority of CRC patients," the authors wrote.

SOURCE:

The study was led by researchers at NYU Grossman School of Medicine and Veterans Affairs New York Harbor Health Care System, and published online July 9, 2026 in Medicine.

LIMITATIONS:

The study population consisted predominantly of male veterans (97.1%), who tend to be older and have more comorbidities compared with the US population, which may limit the generalizability of findings to other populations. Researchers defined screening status cross-sectionally relative to a single point in time rather than assessing longitudinal screening adherence, which may not fully capture the consistency of screening over time that is likely important for defining CRC risk. Veterans may receive screening at non-VA medical facilities, potentially leading to incomplete documentation of screening status and important covariates such as race, ethnicity, and comorbidities. The possibility of residual confounding cannot be excluded despite adjustment for multiple risk factors in the analysis.

DISCLOSURES:

This study received support from NIH grant K08 CA230162 and the AGA Caroline Craig Augustyn & Damian Augustyn Award in Digestive Cancer, both awarded to Peter S. Liang. Liang disclosed receiving research support from Freenome and serving on the advisory boards for Guardant Health and Natera. The remaining authors reported no funding or conflicts of interest to disclose.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

TOPLINE: Interviews with 23 male veterans (aged 35-49 years) at average-risk for colorectal cancer (CRC) and 8 primary care practitioners (PCPs) found broad acceptability of the Colon Age concept, with 96% of patients agreeing to calculation. PCPs describe its potential use to support screening discussions (fecal immunochemical test [FIT] vs colonoscopy) but emphasize workflow barriers, requesting electronic medical record integration and “time neutral” implementation.

METHODOLOGY:

• Researchers conducted semistructured qualitative interviews with 31 participants (23 male veteran patients aged 35-49 years and 8 PCPs) at the Richard L. Roudebush Veterans Affairs Medical Center between June and September 2022.

• Patients were eligible if they were at average risk for CRC, had no prior screening (colonoscopy or fecal immunochemical test [FIT]), no inflammatory bowel disease, and no significant family history of CRC.

• Interviews explored participants' experiences with CRC screening, understanding of the Colon Age tool, and perceived clinical use.

• Audio-recorded interviews were transcribed, deidentified, and analyzed using the constant comparison method with open and focused coding phases until saturation was reached. 

TAKEAWAY:

• Among 23 male veteran patients (mean age 47 years), 96% agreed to have their Colon Age calculated; 68% had a Colon Age below their biological age, 14% higher than their biological age, and 18% equal to their biological age.

• Patients accepted the Colon Age concept, finding it easy to understand and helpful for being informed about their health, though most were unaware of screening options beyond colonoscopy prior to the interview.

• The 8 PCPs (mean age 53 years, 50% female, mean 29 years in practice) interviewed found the tool acceptable and useful for screening conversations, improving uptake, and facilitating shared decision-making, particularly in gray zone cases where screening decisions are unclear.

• PCPs emphasized the need for the tool to be integrated into the electronic medical record system and expressed concerns about time commitment, consistency with practice guidelines, and the validation process, stating they would only use the tool if it were time neutral and evidence-based. 

IN PRACTICE: “Although the age at which to begin colorectal cancer screening in the US was lowered to 45 years in 2018, uptake of screening in persons aged 45 to 49 has been slow,” wrote the authors of the study.

SOURCE:The study was led by researchers at the VA Center for Health Information and Communication. It was published online on July 15 in BMC Primary Care.

LIMITATIONS: The study was conducted at a single VA medical center in the Midwest and all patient participants were male, which may limit generalizability to nonveteran patients, female patients, and non-VA clinicians. The Colon Age tool has limitations, as it was based on a risk prediction model with modest discrimination, and the linkage to screening recommendations was based on arbitrary Surveillance, Epidemiology and End Results thresholds chosen by the tool developers. Additionally, the qualitative nature of the study with a small sample size may not capture the full range of perspectives across diverse health care settings and patient populations.

DISCLOSURES: The primary author received support from Health Services Research and Development, Veterans Administration. Funding for this project was provided by Richard L. Roudebush VA Medical Center Indianapolis, Indiana Center for Health Information, and Communication COIN funds. The authors reported no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

TOPLINE: Interviews with 23 male veterans (aged 35-49 years) at average-risk for colorectal cancer (CRC) and 8 primary care practitioners (PCPs) found broad acceptability of the Colon Age concept, with 96% of patients agreeing to calculation. PCPs describe its potential use to support screening discussions (fecal immunochemical test [FIT] vs colonoscopy) but emphasize workflow barriers, requesting electronic medical record integration and “time neutral” implementation.

METHODOLOGY:

• Researchers conducted semistructured qualitative interviews with 31 participants (23 male veteran patients aged 35-49 years and 8 PCPs) at the Richard L. Roudebush Veterans Affairs Medical Center between June and September 2022.

• Patients were eligible if they were at average risk for CRC, had no prior screening (colonoscopy or fecal immunochemical test [FIT]), no inflammatory bowel disease, and no significant family history of CRC.

• Interviews explored participants' experiences with CRC screening, understanding of the Colon Age tool, and perceived clinical use.

• Audio-recorded interviews were transcribed, deidentified, and analyzed using the constant comparison method with open and focused coding phases until saturation was reached. 

TAKEAWAY:

• Among 23 male veteran patients (mean age 47 years), 96% agreed to have their Colon Age calculated; 68% had a Colon Age below their biological age, 14% higher than their biological age, and 18% equal to their biological age.

• Patients accepted the Colon Age concept, finding it easy to understand and helpful for being informed about their health, though most were unaware of screening options beyond colonoscopy prior to the interview.

• The 8 PCPs (mean age 53 years, 50% female, mean 29 years in practice) interviewed found the tool acceptable and useful for screening conversations, improving uptake, and facilitating shared decision-making, particularly in gray zone cases where screening decisions are unclear.

• PCPs emphasized the need for the tool to be integrated into the electronic medical record system and expressed concerns about time commitment, consistency with practice guidelines, and the validation process, stating they would only use the tool if it were time neutral and evidence-based. 

IN PRACTICE: “Although the age at which to begin colorectal cancer screening in the US was lowered to 45 years in 2018, uptake of screening in persons aged 45 to 49 has been slow,” wrote the authors of the study.

SOURCE:The study was led by researchers at the VA Center for Health Information and Communication. It was published online on July 15 in BMC Primary Care.

LIMITATIONS: The study was conducted at a single VA medical center in the Midwest and all patient participants were male, which may limit generalizability to nonveteran patients, female patients, and non-VA clinicians. The Colon Age tool has limitations, as it was based on a risk prediction model with modest discrimination, and the linkage to screening recommendations was based on arbitrary Surveillance, Epidemiology and End Results thresholds chosen by the tool developers. Additionally, the qualitative nature of the study with a small sample size may not capture the full range of perspectives across diverse health care settings and patient populations.

DISCLOSURES: The primary author received support from Health Services Research and Development, Veterans Administration. Funding for this project was provided by Richard L. Roudebush VA Medical Center Indianapolis, Indiana Center for Health Information, and Communication COIN funds. The authors reported no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

TOPLINE: Interviews with 23 male veterans (aged 35-49 years) at average-risk for colorectal cancer (CRC) and 8 primary care practitioners (PCPs) found broad acceptability of the Colon Age concept, with 96% of patients agreeing to calculation. PCPs describe its potential use to support screening discussions (fecal immunochemical test [FIT] vs colonoscopy) but emphasize workflow barriers, requesting electronic medical record integration and “time neutral” implementation.

METHODOLOGY:

• Researchers conducted semistructured qualitative interviews with 31 participants (23 male veteran patients aged 35-49 years and 8 PCPs) at the Richard L. Roudebush Veterans Affairs Medical Center between June and September 2022.

• Patients were eligible if they were at average risk for CRC, had no prior screening (colonoscopy or fecal immunochemical test [FIT]), no inflammatory bowel disease, and no significant family history of CRC.

• Interviews explored participants' experiences with CRC screening, understanding of the Colon Age tool, and perceived clinical use.

• Audio-recorded interviews were transcribed, deidentified, and analyzed using the constant comparison method with open and focused coding phases until saturation was reached. 

TAKEAWAY:

• Among 23 male veteran patients (mean age 47 years), 96% agreed to have their Colon Age calculated; 68% had a Colon Age below their biological age, 14% higher than their biological age, and 18% equal to their biological age.

• Patients accepted the Colon Age concept, finding it easy to understand and helpful for being informed about their health, though most were unaware of screening options beyond colonoscopy prior to the interview.

• The 8 PCPs (mean age 53 years, 50% female, mean 29 years in practice) interviewed found the tool acceptable and useful for screening conversations, improving uptake, and facilitating shared decision-making, particularly in gray zone cases where screening decisions are unclear.

• PCPs emphasized the need for the tool to be integrated into the electronic medical record system and expressed concerns about time commitment, consistency with practice guidelines, and the validation process, stating they would only use the tool if it were time neutral and evidence-based. 

IN PRACTICE: “Although the age at which to begin colorectal cancer screening in the US was lowered to 45 years in 2018, uptake of screening in persons aged 45 to 49 has been slow,” wrote the authors of the study.

SOURCE:The study was led by researchers at the VA Center for Health Information and Communication. It was published online on July 15 in BMC Primary Care.

LIMITATIONS: The study was conducted at a single VA medical center in the Midwest and all patient participants were male, which may limit generalizability to nonveteran patients, female patients, and non-VA clinicians. The Colon Age tool has limitations, as it was based on a risk prediction model with modest discrimination, and the linkage to screening recommendations was based on arbitrary Surveillance, Epidemiology and End Results thresholds chosen by the tool developers. Additionally, the qualitative nature of the study with a small sample size may not capture the full range of perspectives across diverse health care settings and patient populations.

DISCLOSURES: The primary author received support from Health Services Research and Development, Veterans Administration. Funding for this project was provided by Richard L. Roudebush VA Medical Center Indianapolis, Indiana Center for Health Information, and Communication COIN funds. The authors reported no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

Colorectal cancer (CRC) in the United States continues to move in two different directions — decreasing in older adults and rising in younger adults, especially in those aged 20-49 years, according to the latest statistics from the American Cancer Society (ACS).

The ACS report, published online earlier this month, revealed that CRC incidence rates declined by 2.5% annually in adults aged ≥ 65 years but increased by 3% annually in adults aged 20-49 between 2013 and 2022 — higher than earlier estimates of 1% to 2% annual increases.

The trends are “concerning” and a “stark reminder that we’re seeing a shifting epidemiology,” said Folasade (Fola) May, MD, PhD, MPhil, director of the gastroenterology quality improvement program at UCLA Health in Los Angeles, who wasn’t involved in the analysis.

The report highlights the need for better education and symptom awareness — including bleeding, iron deficiency symptoms, and changes in bowel habits — among patients and doctors, who may not routinely consider cancer in younger adults, May explained.

“Because so many of the young people diagnosed present with advanced stage disease, early workup is critical to saving lives,” she said.

Rapidly Changing Landscape

In the United States, CRC is the third-most commonly diagnosed cancer in both men and women. CRC is also the second-leading cause of cancer-related deaths and the leading cause in adults aged < 50 years.

“After decades of progress, the risk of dying from colorectal cancer is climbing in younger generations of men and women, confirming a real uptick in disease because of something we’re doing or some other exposure,” Rebecca Siegel, MPH, senior scientific director of surveillance research at ACS and lead author of the report, said in a statement.

For the latest CRC statistics report, ACS scientists analyzed population-based registries, including the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program, and mortality data from the CDC’s National Center for Health Statistics.

The report estimated that 158,850 new CRC cases will be diagnosed in the US in 2026, including 108,860 colon cancers and 49,990 rectal cancers; an estimated 55,230 people will die from the disease.

Overall, CRC incidence declined by 0.9% annually from 2013 to 2022, driven by decreases of 2.5% per year in adults aged ≥ 65 years. During the same period, however, incidence rates rose by about 3% per year in adults aged 20-49 years and by 0.4% per year in those aged 50-64 years. CRC mortality also continued to trend downward in adults aged ≥ 65 years by > 2% per year, but mortality increased by 1% per year in adults aged < 50 years since 2004 and in adults aged 50-64 years since 2019.

Nearly half of new CRC cases (45%) now occur in adults aged < 65 years, up from 27% in 1995, illustrating a major shift toward younger age groups, the authors said. Half of early-onset cases occur in people aged 45-49 years who are now eligible for screening, and 3 of 4 early-onset CRC cases are diagnosed at an advanced stage, including about 27% with distant metastases.

“This is partly because of less screening, but it also reflects diagnostic delays,” according to Siegel and coauthors, who noted data show screening uptake remains low in individuals aged 45-49 (37%) and 50-54 (55%) years. The incidence of early-onset CRC increased across all racial and ethnic groups in the US, from 2% annually in Black individuals to 4% annually in Hispanic individuals between 2013 and 2022.

Aside from early-onset trends, the analysis found that tumor location trends shifted as well. Rectal cancer incidence increased in all ages combined (by 1% per year from 2018 to 2022), reversing decades of decline and now accounting for nearly one third of all CRC, compared with 27% in the mid-2000s.

The report also indicated that racial and ethnic disparities persist. Alaska Native individuals had the highest CRC incidence (80.9 per 100,000) and mortality (31.5 per 100,000) in the US, more than twofold that of White patients (35.2 and 12.9 per 100,000, respectively). Asian American, Native Hawaiian, and other Pacific Islanders had the lowest incidence (28.5 per 100,000) and mortality rates (9.2 per 100,000).

Although cancer registries like SEER are not perfect, they are “the best data we have” and overall the SEER data “very reliably represent what is going on in the US population,” May said.

The latest findings also further underscore that CRC is “worsening among younger generations and highlight the immediate need for eligible adults to begin screening at the recommended age of 45,” William Dahut, MD, ACS chief scientific officer, said in the statement.

The study had no commercial funding. The authors and May reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Colorectal cancer (CRC) in the United States continues to move in two different directions — decreasing in older adults and rising in younger adults, especially in those aged 20-49 years, according to the latest statistics from the American Cancer Society (ACS).

The ACS report, published online earlier this month, revealed that CRC incidence rates declined by 2.5% annually in adults aged ≥ 65 years but increased by 3% annually in adults aged 20-49 between 2013 and 2022 — higher than earlier estimates of 1% to 2% annual increases.

The trends are “concerning” and a “stark reminder that we’re seeing a shifting epidemiology,” said Folasade (Fola) May, MD, PhD, MPhil, director of the gastroenterology quality improvement program at UCLA Health in Los Angeles, who wasn’t involved in the analysis.

The report highlights the need for better education and symptom awareness — including bleeding, iron deficiency symptoms, and changes in bowel habits — among patients and doctors, who may not routinely consider cancer in younger adults, May explained.

“Because so many of the young people diagnosed present with advanced stage disease, early workup is critical to saving lives,” she said.

Rapidly Changing Landscape

In the United States, CRC is the third-most commonly diagnosed cancer in both men and women. CRC is also the second-leading cause of cancer-related deaths and the leading cause in adults aged < 50 years.

“After decades of progress, the risk of dying from colorectal cancer is climbing in younger generations of men and women, confirming a real uptick in disease because of something we’re doing or some other exposure,” Rebecca Siegel, MPH, senior scientific director of surveillance research at ACS and lead author of the report, said in a statement.

For the latest CRC statistics report, ACS scientists analyzed population-based registries, including the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program, and mortality data from the CDC’s National Center for Health Statistics.

The report estimated that 158,850 new CRC cases will be diagnosed in the US in 2026, including 108,860 colon cancers and 49,990 rectal cancers; an estimated 55,230 people will die from the disease.

Overall, CRC incidence declined by 0.9% annually from 2013 to 2022, driven by decreases of 2.5% per year in adults aged ≥ 65 years. During the same period, however, incidence rates rose by about 3% per year in adults aged 20-49 years and by 0.4% per year in those aged 50-64 years. CRC mortality also continued to trend downward in adults aged ≥ 65 years by > 2% per year, but mortality increased by 1% per year in adults aged < 50 years since 2004 and in adults aged 50-64 years since 2019.

Nearly half of new CRC cases (45%) now occur in adults aged < 65 years, up from 27% in 1995, illustrating a major shift toward younger age groups, the authors said. Half of early-onset cases occur in people aged 45-49 years who are now eligible for screening, and 3 of 4 early-onset CRC cases are diagnosed at an advanced stage, including about 27% with distant metastases.

“This is partly because of less screening, but it also reflects diagnostic delays,” according to Siegel and coauthors, who noted data show screening uptake remains low in individuals aged 45-49 (37%) and 50-54 (55%) years. The incidence of early-onset CRC increased across all racial and ethnic groups in the US, from 2% annually in Black individuals to 4% annually in Hispanic individuals between 2013 and 2022.

Aside from early-onset trends, the analysis found that tumor location trends shifted as well. Rectal cancer incidence increased in all ages combined (by 1% per year from 2018 to 2022), reversing decades of decline and now accounting for nearly one third of all CRC, compared with 27% in the mid-2000s.

The report also indicated that racial and ethnic disparities persist. Alaska Native individuals had the highest CRC incidence (80.9 per 100,000) and mortality (31.5 per 100,000) in the US, more than twofold that of White patients (35.2 and 12.9 per 100,000, respectively). Asian American, Native Hawaiian, and other Pacific Islanders had the lowest incidence (28.5 per 100,000) and mortality rates (9.2 per 100,000).

Although cancer registries like SEER are not perfect, they are “the best data we have” and overall the SEER data “very reliably represent what is going on in the US population,” May said.

The latest findings also further underscore that CRC is “worsening among younger generations and highlight the immediate need for eligible adults to begin screening at the recommended age of 45,” William Dahut, MD, ACS chief scientific officer, said in the statement.

The study had no commercial funding. The authors and May reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Colorectal cancer (CRC) in the United States continues to move in two different directions — decreasing in older adults and rising in younger adults, especially in those aged 20-49 years, according to the latest statistics from the American Cancer Society (ACS).

The ACS report, published online earlier this month, revealed that CRC incidence rates declined by 2.5% annually in adults aged ≥ 65 years but increased by 3% annually in adults aged 20-49 between 2013 and 2022 — higher than earlier estimates of 1% to 2% annual increases.

The trends are “concerning” and a “stark reminder that we’re seeing a shifting epidemiology,” said Folasade (Fola) May, MD, PhD, MPhil, director of the gastroenterology quality improvement program at UCLA Health in Los Angeles, who wasn’t involved in the analysis.

The report highlights the need for better education and symptom awareness — including bleeding, iron deficiency symptoms, and changes in bowel habits — among patients and doctors, who may not routinely consider cancer in younger adults, May explained.

“Because so many of the young people diagnosed present with advanced stage disease, early workup is critical to saving lives,” she said.

Rapidly Changing Landscape

In the United States, CRC is the third-most commonly diagnosed cancer in both men and women. CRC is also the second-leading cause of cancer-related deaths and the leading cause in adults aged < 50 years.

“After decades of progress, the risk of dying from colorectal cancer is climbing in younger generations of men and women, confirming a real uptick in disease because of something we’re doing or some other exposure,” Rebecca Siegel, MPH, senior scientific director of surveillance research at ACS and lead author of the report, said in a statement.

For the latest CRC statistics report, ACS scientists analyzed population-based registries, including the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program, and mortality data from the CDC’s National Center for Health Statistics.

The report estimated that 158,850 new CRC cases will be diagnosed in the US in 2026, including 108,860 colon cancers and 49,990 rectal cancers; an estimated 55,230 people will die from the disease.

Overall, CRC incidence declined by 0.9% annually from 2013 to 2022, driven by decreases of 2.5% per year in adults aged ≥ 65 years. During the same period, however, incidence rates rose by about 3% per year in adults aged 20-49 years and by 0.4% per year in those aged 50-64 years. CRC mortality also continued to trend downward in adults aged ≥ 65 years by > 2% per year, but mortality increased by 1% per year in adults aged < 50 years since 2004 and in adults aged 50-64 years since 2019.

Nearly half of new CRC cases (45%) now occur in adults aged < 65 years, up from 27% in 1995, illustrating a major shift toward younger age groups, the authors said. Half of early-onset cases occur in people aged 45-49 years who are now eligible for screening, and 3 of 4 early-onset CRC cases are diagnosed at an advanced stage, including about 27% with distant metastases.

“This is partly because of less screening, but it also reflects diagnostic delays,” according to Siegel and coauthors, who noted data show screening uptake remains low in individuals aged 45-49 (37%) and 50-54 (55%) years. The incidence of early-onset CRC increased across all racial and ethnic groups in the US, from 2% annually in Black individuals to 4% annually in Hispanic individuals between 2013 and 2022.

Aside from early-onset trends, the analysis found that tumor location trends shifted as well. Rectal cancer incidence increased in all ages combined (by 1% per year from 2018 to 2022), reversing decades of decline and now accounting for nearly one third of all CRC, compared with 27% in the mid-2000s.

The report also indicated that racial and ethnic disparities persist. Alaska Native individuals had the highest CRC incidence (80.9 per 100,000) and mortality (31.5 per 100,000) in the US, more than twofold that of White patients (35.2 and 12.9 per 100,000, respectively). Asian American, Native Hawaiian, and other Pacific Islanders had the lowest incidence (28.5 per 100,000) and mortality rates (9.2 per 100,000).

Although cancer registries like SEER are not perfect, they are “the best data we have” and overall the SEER data “very reliably represent what is going on in the US population,” May said.

The latest findings also further underscore that CRC is “worsening among younger generations and highlight the immediate need for eligible adults to begin screening at the recommended age of 45,” William Dahut, MD, ACS chief scientific officer, said in the statement.

The study had no commercial funding. The authors and May reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

TOPLINE: 

A recalibrated environmental risk score for colorectal cancer (CRC) shows improved predictive performance in a study of 227,504 male veterans. The veteran-tailored score could help personalize screening better than previous models.

METHODOLOGY: 

• Demographic, lifestyle, and CRC data from 2011 to 2022 were abstracted from survey responses and health records of 227,504 male Million Veteran Program (MVP) participants, with complete data needed to construct the environmental risk score (e-Score).
• Researchers randomly split the male sample into 2 halves to produce training and validation samples (each n = 113,752; CRC cases n = 590) using simple random sampling with strata based on the CRC variable.
• Weighting for each environmental factor's effect size was recalculated using US Department of Veterans Affairs training data to create a recalibrated e-Score, which was compared with the original weighted e-Score in the validation sample.
• Analysis included nested multiple logistic regression models testing associations between quintiles for recalibrated and original e-Scores, with likelihood ratio tests used to compare model performance.
• Factors used to construct the e-Score included BMI, height, diabetes diagnosis, aspirin use, nonsteroidal anti-inflammatory drug use, educational attainment, physical activity level, smoking status, alcohol use, and dietary intake of fiber, calcium, folate, processed meats, red meat, fruits, vegetables, and total energy.

TAKEAWAY:

• The recalibrated e-Score showed a significant association with CRC, with higher quintiles indicating increased risk.
• In the validation sample, the recalibrated e-Score model significantly improved the base model performance (P < .001), while the original GECCO e-Score model did not show significant improvement (P = .07).
• The recalibrated e-Score model quintile 5 was associated with significantly higher odds for CRC compared with quintile 1 (odds ratio [OR], 1.79; 95% CI, 1.38-2.33; P for trend < .001).
• Black participants had higher odds for CRC compared with the White reference group across all models (base model OR, 1.46; 95% CI, 1.13-1.92; GECCO e-Score model OR, 1.44; 95% CI, 1.09-1.88; and recalibrated e-Score model OR, 1.38; 95% CI, 1.05-1.82).

IN PRACTICE:

"Despite the robust methods used in the work by the GECCO study upon which our study was based, an e-Score using their study’s weighting was not significantly associated with colorectal cancer among the male veteran sample. However, data from nearly a quarter million (n = 227,504) male US veteran participants of the MVP were used to recalibrate the e-Score to be veteran specific, and the recalibrated e-Score validation showed that it was significantly associated with colorectal cancer," wrote the authors of the study.

SOURCE:

The study was led by April R. Williams, US Department of Veterans Affairs Million Veteran Program Coordinating Center in Boston. It was published online in Cancer Epidemiology, Biomarkers & Prevention.

LIMITATIONS:

The study's limitations include potential recall and self-selection bias due to the use of self-reported data from the MVP. The generalizability of the findings may be limited to the veteran population, and the sample of Black veterans may have been insufficient for conclusive analysis. Additionally, the study did not include female participants due to insufficient data for a veteran-specific e-Score.

DISCLOSURES:

B.A. Sullivan disclosed receiving grants from the American Gastroenterological Association. D. Lieberman reported support from Geneoscopy, UDX, and ColoWrap. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

TOPLINE: 

A recalibrated environmental risk score for colorectal cancer (CRC) shows improved predictive performance in a study of 227,504 male veterans. The veteran-tailored score could help personalize screening better than previous models.

METHODOLOGY: 

• Demographic, lifestyle, and CRC data from 2011 to 2022 were abstracted from survey responses and health records of 227,504 male Million Veteran Program (MVP) participants, with complete data needed to construct the environmental risk score (e-Score).
• Researchers randomly split the male sample into 2 halves to produce training and validation samples (each n = 113,752; CRC cases n = 590) using simple random sampling with strata based on the CRC variable.
• Weighting for each environmental factor's effect size was recalculated using US Department of Veterans Affairs training data to create a recalibrated e-Score, which was compared with the original weighted e-Score in the validation sample.
• Analysis included nested multiple logistic regression models testing associations between quintiles for recalibrated and original e-Scores, with likelihood ratio tests used to compare model performance.
• Factors used to construct the e-Score included BMI, height, diabetes diagnosis, aspirin use, nonsteroidal anti-inflammatory drug use, educational attainment, physical activity level, smoking status, alcohol use, and dietary intake of fiber, calcium, folate, processed meats, red meat, fruits, vegetables, and total energy.

TAKEAWAY:

• The recalibrated e-Score showed a significant association with CRC, with higher quintiles indicating increased risk.
• In the validation sample, the recalibrated e-Score model significantly improved the base model performance (P < .001), while the original GECCO e-Score model did not show significant improvement (P = .07).
• The recalibrated e-Score model quintile 5 was associated with significantly higher odds for CRC compared with quintile 1 (odds ratio [OR], 1.79; 95% CI, 1.38-2.33; P for trend < .001).
• Black participants had higher odds for CRC compared with the White reference group across all models (base model OR, 1.46; 95% CI, 1.13-1.92; GECCO e-Score model OR, 1.44; 95% CI, 1.09-1.88; and recalibrated e-Score model OR, 1.38; 95% CI, 1.05-1.82).

IN PRACTICE:

"Despite the robust methods used in the work by the GECCO study upon which our study was based, an e-Score using their study’s weighting was not significantly associated with colorectal cancer among the male veteran sample. However, data from nearly a quarter million (n = 227,504) male US veteran participants of the MVP were used to recalibrate the e-Score to be veteran specific, and the recalibrated e-Score validation showed that it was significantly associated with colorectal cancer," wrote the authors of the study.

SOURCE:

The study was led by April R. Williams, US Department of Veterans Affairs Million Veteran Program Coordinating Center in Boston. It was published online in Cancer Epidemiology, Biomarkers & Prevention.

LIMITATIONS:

The study's limitations include potential recall and self-selection bias due to the use of self-reported data from the MVP. The generalizability of the findings may be limited to the veteran population, and the sample of Black veterans may have been insufficient for conclusive analysis. Additionally, the study did not include female participants due to insufficient data for a veteran-specific e-Score.

DISCLOSURES:

B.A. Sullivan disclosed receiving grants from the American Gastroenterological Association. D. Lieberman reported support from Geneoscopy, UDX, and ColoWrap. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

TOPLINE: 

A recalibrated environmental risk score for colorectal cancer (CRC) shows improved predictive performance in a study of 227,504 male veterans. The veteran-tailored score could help personalize screening better than previous models.

METHODOLOGY: 

• Demographic, lifestyle, and CRC data from 2011 to 2022 were abstracted from survey responses and health records of 227,504 male Million Veteran Program (MVP) participants, with complete data needed to construct the environmental risk score (e-Score).
• Researchers randomly split the male sample into 2 halves to produce training and validation samples (each n = 113,752; CRC cases n = 590) using simple random sampling with strata based on the CRC variable.
• Weighting for each environmental factor's effect size was recalculated using US Department of Veterans Affairs training data to create a recalibrated e-Score, which was compared with the original weighted e-Score in the validation sample.
• Analysis included nested multiple logistic regression models testing associations between quintiles for recalibrated and original e-Scores, with likelihood ratio tests used to compare model performance.
• Factors used to construct the e-Score included BMI, height, diabetes diagnosis, aspirin use, nonsteroidal anti-inflammatory drug use, educational attainment, physical activity level, smoking status, alcohol use, and dietary intake of fiber, calcium, folate, processed meats, red meat, fruits, vegetables, and total energy.

TAKEAWAY:

• The recalibrated e-Score showed a significant association with CRC, with higher quintiles indicating increased risk.
• In the validation sample, the recalibrated e-Score model significantly improved the base model performance (P < .001), while the original GECCO e-Score model did not show significant improvement (P = .07).
• The recalibrated e-Score model quintile 5 was associated with significantly higher odds for CRC compared with quintile 1 (odds ratio [OR], 1.79; 95% CI, 1.38-2.33; P for trend < .001).
• Black participants had higher odds for CRC compared with the White reference group across all models (base model OR, 1.46; 95% CI, 1.13-1.92; GECCO e-Score model OR, 1.44; 95% CI, 1.09-1.88; and recalibrated e-Score model OR, 1.38; 95% CI, 1.05-1.82).

IN PRACTICE:

"Despite the robust methods used in the work by the GECCO study upon which our study was based, an e-Score using their study’s weighting was not significantly associated with colorectal cancer among the male veteran sample. However, data from nearly a quarter million (n = 227,504) male US veteran participants of the MVP were used to recalibrate the e-Score to be veteran specific, and the recalibrated e-Score validation showed that it was significantly associated with colorectal cancer," wrote the authors of the study.

SOURCE:

The study was led by April R. Williams, US Department of Veterans Affairs Million Veteran Program Coordinating Center in Boston. It was published online in Cancer Epidemiology, Biomarkers & Prevention.

LIMITATIONS:

The study's limitations include potential recall and self-selection bias due to the use of self-reported data from the MVP. The generalizability of the findings may be limited to the veteran population, and the sample of Black veterans may have been insufficient for conclusive analysis. Additionally, the study did not include female participants due to insufficient data for a veteran-specific e-Score.

DISCLOSURES:

B.A. Sullivan disclosed receiving grants from the American Gastroenterological Association. D. Lieberman reported support from Geneoscopy, UDX, and ColoWrap. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

First, the good news: Fewer Americans aged < 50 years are dying from cancer vs just a decade ago — reflecting progress in prevention, early detection, and treatment. There is, however, one big exception. Colorectal cancer mortality has been steadily inching up, and the disease now stands as the leading cause of cancer death in this age group, up from the fifth-leading in the early 1990s.

Those are the major findings of a recent study by the American Cancer Society (ACS), published as a research letter in JAMA.

Using SEER data, researchers found that the overall age-adjusted cancer death rate among Americans aged < 50 years dropped by 44% between 1990 and 2023 — from 25.5 to 14.2 per 100,000. And for 4 of the 5 leading causes of cancer death, there were mean annual declines from 2014 to 2023. The biggest change was in lung cancer deaths, which fell by an average of 5.7% per year. Meanwhile, leukemia and breast cancer deaths showed annual declines of 2.3% and 1.4%, respectively, despite rising incidences of both diseases among younger Americans.

The outlier is colorectal cancer, where mortality has been rising by about 1% per year since 2005. And it’s a pattern seen in both men and women.

Study coauthor Nikita Sandeep Wagle, PhD, MBBS, principal scientist, Cancer Surveillance Research at the ACS, and Arif Kamal, MD, ACS chief patient officer, discussed the research and its implications with Medscape Medical News.

Can you offer some possible reasons for the declining mortality in most of the cancers you studied?

Wagle: Mortality is going down for most of the cancers because we are getting better at finding cancers earlier and treating them more effectively. We have also seen improvements in screening, imaging, and therapy, and that means more people are being diagnosed at earlier stages and are surviving longer after diagnosis.

Regarding the rise in colorectal cancer mortality, do you think it's due to the rising incidence of early-onset colorectal cancer?

Kamal: Partially, but not completely, because the relationship between incidence and mortality is not always straightforward. For example, breast cancer incidence has been increasing, while mortality is going down. The rising mortality in people younger than 50 years is likely suggestive of more aggressive cancers being diagnosed — potentially secondary to environmental, dietary, or lifestyle factors. The colon is a unique organ because everything we put in our bodies passes through the colon, so food-based risk factors — for example, low fiber intake, red meat, and ultra-processed foods — are increasingly rising to the top as culprits.

Further, we know that only about 25% of people between the ages of 45 and 50 years are up to date with recommended colon cancer screenings, which can lead to later-stage diagnoses and thus higher mortality. So higher mortality speaks to the need to focus on lifestyle and diet changes and get more younger people to complete recommended cancer screenings.

Wagle: I think the “why” of your question is very important. Many researchers are trying to understand possible causes, such as diet, lifestyle, environmental factors, and genetics. But we cannot pinpoint one single cause. We need even more focus on research toward understanding the etiology of early-onset colorectal cancer.

What makes colorectal cancer different is that, unlike some other major cancers in this age group where mortality has declined despite rising incidence, roughly 3 in 4 colorectal cancers diagnosed in people younger than 50 years are [regional or distant], where the outcomes are worse.

Can you contextualize the rise in colorectal cancer mortality? What is the absolute rate among younger Americans now?

Wagle: It is around two deaths per 100,000 population in 2023 for people younger than 50 years. That number may not seem large, but the upward trend — a 1.1% annual increase from 2014 to 2023 — is concerning when you think about how overall mortality in this age group has dropped substantially over the past few decades. Colorectal cancer is moving in the opposite direction. I think the hopeful part is that it is also one of the most preventable cancers. Screening can stop cancer before it starts by removing precancerous polyps. Early-stage disease is highly treatable, and outcomes are better. That means better awareness and timely screening could make a real difference.

How can clinicians use this new information with regard to screening?

Wagle: For cancers with established screening guidelines, such as colorectal cancer, clinicians should continue to emphasize guideline-based screening and individualized risk assessment.

For colorectal cancer, screening now is recommended to start at age 45 for individuals at average risk, and earlier for [some], due to family history or other risk factors. Clinicians can use these findings to remind younger individuals that colorectal cancer is not only a disease of older adults and that screening at the recommended age can save lives.

In addition, red-flag symptoms such as persistent rectal bleeding, unexplained abdominal pain, difficulty in bowel movements, or signs of anemia should prompt appropriate evaluation in younger individuals.

Kamal: Clinicians should continue to emphasize timely completion of regular screening, starting at age 45 [for average-risk people]. Many still believe that the recommended starting age is 50 or that colonoscopy is the only way to get screened. Highlighting home-based screening options often helps patients make cancer screening logistically fit better into their busy lives.

Could you elaborate on the red-flag symptoms you mentioned, and what is an appropriate evaluation in younger individuals?

Kamal: Appropriate evaluation for any suspected bleeding — bright red or black and tarry — starts with an in-office evaluation by a primary care physician. Referral to a specialist, such as a gastroenterologist or surgeon, is done later, typically for direct visualization, such as with a colonoscopy. Rarely, imaging such as CT scans or ultrasounds is performed. Overall, because of the rising incidence of colon cancer in younger people, any concerning symptoms should be reported to a physician for an in-office evaluation as the first step.

Do these findings suggest that the starting age for average-risk people should be lowered—to age 40, for example?

Kamal: ACS screening guidelines for all cancers are part of an ongoing guideline development process by ACS scientists and volunteers. We monitor medical and scientific literature for new evidence that may support a change in current guidelines or the development of new guidelines and for information about cancer screening that should be conveyed to clinicians and target populations.

Keith Mulvihill is a freelance writer based in New York City.

A version of this article first appeared on Medscape.com.

First, the good news: Fewer Americans aged < 50 years are dying from cancer vs just a decade ago — reflecting progress in prevention, early detection, and treatment. There is, however, one big exception. Colorectal cancer mortality has been steadily inching up, and the disease now stands as the leading cause of cancer death in this age group, up from the fifth-leading in the early 1990s.

Those are the major findings of a recent study by the American Cancer Society (ACS), published as a research letter in JAMA.

Using SEER data, researchers found that the overall age-adjusted cancer death rate among Americans aged < 50 years dropped by 44% between 1990 and 2023 — from 25.5 to 14.2 per 100,000. And for 4 of the 5 leading causes of cancer death, there were mean annual declines from 2014 to 2023. The biggest change was in lung cancer deaths, which fell by an average of 5.7% per year. Meanwhile, leukemia and breast cancer deaths showed annual declines of 2.3% and 1.4%, respectively, despite rising incidences of both diseases among younger Americans.

The outlier is colorectal cancer, where mortality has been rising by about 1% per year since 2005. And it’s a pattern seen in both men and women.

Study coauthor Nikita Sandeep Wagle, PhD, MBBS, principal scientist, Cancer Surveillance Research at the ACS, and Arif Kamal, MD, ACS chief patient officer, discussed the research and its implications with Medscape Medical News.

Can you offer some possible reasons for the declining mortality in most of the cancers you studied?

Wagle: Mortality is going down for most of the cancers because we are getting better at finding cancers earlier and treating them more effectively. We have also seen improvements in screening, imaging, and therapy, and that means more people are being diagnosed at earlier stages and are surviving longer after diagnosis.

Regarding the rise in colorectal cancer mortality, do you think it's due to the rising incidence of early-onset colorectal cancer?

Kamal: Partially, but not completely, because the relationship between incidence and mortality is not always straightforward. For example, breast cancer incidence has been increasing, while mortality is going down. The rising mortality in people younger than 50 years is likely suggestive of more aggressive cancers being diagnosed — potentially secondary to environmental, dietary, or lifestyle factors. The colon is a unique organ because everything we put in our bodies passes through the colon, so food-based risk factors — for example, low fiber intake, red meat, and ultra-processed foods — are increasingly rising to the top as culprits.

Further, we know that only about 25% of people between the ages of 45 and 50 years are up to date with recommended colon cancer screenings, which can lead to later-stage diagnoses and thus higher mortality. So higher mortality speaks to the need to focus on lifestyle and diet changes and get more younger people to complete recommended cancer screenings.

Wagle: I think the “why” of your question is very important. Many researchers are trying to understand possible causes, such as diet, lifestyle, environmental factors, and genetics. But we cannot pinpoint one single cause. We need even more focus on research toward understanding the etiology of early-onset colorectal cancer.

What makes colorectal cancer different is that, unlike some other major cancers in this age group where mortality has declined despite rising incidence, roughly 3 in 4 colorectal cancers diagnosed in people younger than 50 years are [regional or distant], where the outcomes are worse.

Can you contextualize the rise in colorectal cancer mortality? What is the absolute rate among younger Americans now?

Wagle: It is around two deaths per 100,000 population in 2023 for people younger than 50 years. That number may not seem large, but the upward trend — a 1.1% annual increase from 2014 to 2023 — is concerning when you think about how overall mortality in this age group has dropped substantially over the past few decades. Colorectal cancer is moving in the opposite direction. I think the hopeful part is that it is also one of the most preventable cancers. Screening can stop cancer before it starts by removing precancerous polyps. Early-stage disease is highly treatable, and outcomes are better. That means better awareness and timely screening could make a real difference.

How can clinicians use this new information with regard to screening?

Wagle: For cancers with established screening guidelines, such as colorectal cancer, clinicians should continue to emphasize guideline-based screening and individualized risk assessment.

For colorectal cancer, screening now is recommended to start at age 45 for individuals at average risk, and earlier for [some], due to family history or other risk factors. Clinicians can use these findings to remind younger individuals that colorectal cancer is not only a disease of older adults and that screening at the recommended age can save lives.

In addition, red-flag symptoms such as persistent rectal bleeding, unexplained abdominal pain, difficulty in bowel movements, or signs of anemia should prompt appropriate evaluation in younger individuals.

Kamal: Clinicians should continue to emphasize timely completion of regular screening, starting at age 45 [for average-risk people]. Many still believe that the recommended starting age is 50 or that colonoscopy is the only way to get screened. Highlighting home-based screening options often helps patients make cancer screening logistically fit better into their busy lives.

Could you elaborate on the red-flag symptoms you mentioned, and what is an appropriate evaluation in younger individuals?

Kamal: Appropriate evaluation for any suspected bleeding — bright red or black and tarry — starts with an in-office evaluation by a primary care physician. Referral to a specialist, such as a gastroenterologist or surgeon, is done later, typically for direct visualization, such as with a colonoscopy. Rarely, imaging such as CT scans or ultrasounds is performed. Overall, because of the rising incidence of colon cancer in younger people, any concerning symptoms should be reported to a physician for an in-office evaluation as the first step.

Do these findings suggest that the starting age for average-risk people should be lowered—to age 40, for example?

Kamal: ACS screening guidelines for all cancers are part of an ongoing guideline development process by ACS scientists and volunteers. We monitor medical and scientific literature for new evidence that may support a change in current guidelines or the development of new guidelines and for information about cancer screening that should be conveyed to clinicians and target populations.

Keith Mulvihill is a freelance writer based in New York City.

A version of this article first appeared on Medscape.com.

First, the good news: Fewer Americans aged < 50 years are dying from cancer vs just a decade ago — reflecting progress in prevention, early detection, and treatment. There is, however, one big exception. Colorectal cancer mortality has been steadily inching up, and the disease now stands as the leading cause of cancer death in this age group, up from the fifth-leading in the early 1990s.

Those are the major findings of a recent study by the American Cancer Society (ACS), published as a research letter in JAMA.

Using SEER data, researchers found that the overall age-adjusted cancer death rate among Americans aged < 50 years dropped by 44% between 1990 and 2023 — from 25.5 to 14.2 per 100,000. And for 4 of the 5 leading causes of cancer death, there were mean annual declines from 2014 to 2023. The biggest change was in lung cancer deaths, which fell by an average of 5.7% per year. Meanwhile, leukemia and breast cancer deaths showed annual declines of 2.3% and 1.4%, respectively, despite rising incidences of both diseases among younger Americans.

The outlier is colorectal cancer, where mortality has been rising by about 1% per year since 2005. And it’s a pattern seen in both men and women.

Study coauthor Nikita Sandeep Wagle, PhD, MBBS, principal scientist, Cancer Surveillance Research at the ACS, and Arif Kamal, MD, ACS chief patient officer, discussed the research and its implications with Medscape Medical News.

Can you offer some possible reasons for the declining mortality in most of the cancers you studied?

Wagle: Mortality is going down for most of the cancers because we are getting better at finding cancers earlier and treating them more effectively. We have also seen improvements in screening, imaging, and therapy, and that means more people are being diagnosed at earlier stages and are surviving longer after diagnosis.

Regarding the rise in colorectal cancer mortality, do you think it's due to the rising incidence of early-onset colorectal cancer?

Kamal: Partially, but not completely, because the relationship between incidence and mortality is not always straightforward. For example, breast cancer incidence has been increasing, while mortality is going down. The rising mortality in people younger than 50 years is likely suggestive of more aggressive cancers being diagnosed — potentially secondary to environmental, dietary, or lifestyle factors. The colon is a unique organ because everything we put in our bodies passes through the colon, so food-based risk factors — for example, low fiber intake, red meat, and ultra-processed foods — are increasingly rising to the top as culprits.

Further, we know that only about 25% of people between the ages of 45 and 50 years are up to date with recommended colon cancer screenings, which can lead to later-stage diagnoses and thus higher mortality. So higher mortality speaks to the need to focus on lifestyle and diet changes and get more younger people to complete recommended cancer screenings.

Wagle: I think the “why” of your question is very important. Many researchers are trying to understand possible causes, such as diet, lifestyle, environmental factors, and genetics. But we cannot pinpoint one single cause. We need even more focus on research toward understanding the etiology of early-onset colorectal cancer.

What makes colorectal cancer different is that, unlike some other major cancers in this age group where mortality has declined despite rising incidence, roughly 3 in 4 colorectal cancers diagnosed in people younger than 50 years are [regional or distant], where the outcomes are worse.

Can you contextualize the rise in colorectal cancer mortality? What is the absolute rate among younger Americans now?

Wagle: It is around two deaths per 100,000 population in 2023 for people younger than 50 years. That number may not seem large, but the upward trend — a 1.1% annual increase from 2014 to 2023 — is concerning when you think about how overall mortality in this age group has dropped substantially over the past few decades. Colorectal cancer is moving in the opposite direction. I think the hopeful part is that it is also one of the most preventable cancers. Screening can stop cancer before it starts by removing precancerous polyps. Early-stage disease is highly treatable, and outcomes are better. That means better awareness and timely screening could make a real difference.

How can clinicians use this new information with regard to screening?

Wagle: For cancers with established screening guidelines, such as colorectal cancer, clinicians should continue to emphasize guideline-based screening and individualized risk assessment.

For colorectal cancer, screening now is recommended to start at age 45 for individuals at average risk, and earlier for [some], due to family history or other risk factors. Clinicians can use these findings to remind younger individuals that colorectal cancer is not only a disease of older adults and that screening at the recommended age can save lives.

In addition, red-flag symptoms such as persistent rectal bleeding, unexplained abdominal pain, difficulty in bowel movements, or signs of anemia should prompt appropriate evaluation in younger individuals.

Kamal: Clinicians should continue to emphasize timely completion of regular screening, starting at age 45 [for average-risk people]. Many still believe that the recommended starting age is 50 or that colonoscopy is the only way to get screened. Highlighting home-based screening options often helps patients make cancer screening logistically fit better into their busy lives.

Could you elaborate on the red-flag symptoms you mentioned, and what is an appropriate evaluation in younger individuals?

Kamal: Appropriate evaluation for any suspected bleeding — bright red or black and tarry — starts with an in-office evaluation by a primary care physician. Referral to a specialist, such as a gastroenterologist or surgeon, is done later, typically for direct visualization, such as with a colonoscopy. Rarely, imaging such as CT scans or ultrasounds is performed. Overall, because of the rising incidence of colon cancer in younger people, any concerning symptoms should be reported to a physician for an in-office evaluation as the first step.

Do these findings suggest that the starting age for average-risk people should be lowered—to age 40, for example?

Kamal: ACS screening guidelines for all cancers are part of an ongoing guideline development process by ACS scientists and volunteers. We monitor medical and scientific literature for new evidence that may support a change in current guidelines or the development of new guidelines and for information about cancer screening that should be conveyed to clinicians and target populations.

Keith Mulvihill is a freelance writer based in New York City.

A version of this article first appeared on Medscape.com.

The targeted therapy combination of encorafenib and cetuximab with FOLFIRI (leucovorin/5-fluorouracil [FU]/irinotecan) chemotherapy may be a new first-line option for patients with BRAF V600E-mutant metastatic colorectal cancer (CRC), according to new results from the BREAKWATER trial.

After a median follow-up of about 10 months, response rates were significantly better with encorafenib and cetuximab plus FOLFIRI than with FOLFIRI alone — without increasing side effects.

The findings, presented at the ASCO Gastrointestinal Cancers Symposium 2026, point to a potential new option for the 20%-25% of patients with BRAF V600E-mutant metastatic CRC who receive FOLFIRI as their chemotherapy.

Based on previous results from BREAKWATER, the FDA granted accelerated approval to first-line encorafenib (Braftovi) and cetuximab (Erbitux) plus mFOLFOX6 for this patient population. That regimen doubled median overall survival compared with standard chemotherapy with or without bevacizumab.

Cohort 3 of BREAKWATER was designed to address a specific question: Are the benefits with the targeted therapy duo a “FOLFOX-specific phenomenon?” lead investigator Scott Kopetz, MD, PhD, of MD Anderson Cancer Center, Houston, said during a press briefing.

Based on these early results, the answer is no. Instead, Kopetz said, there appears to be a “broader synergy” between the targeted therapies and cytotoxic chemotherapy.

Joel Saltzman, MD, ASCO expert in gastrointestinal cancers based at Taussig Cancer Center, Cleveland Clinic in Cleveland, agreed.

“The additional data from the BREAKWATER trial reveals that it is the targeted therapy backbone that provides the better disease control and response rate in BRAF V600E-mutant colorectal cancers,” he said.

BRAF V600E mutations occur in up to 12% of patients with metastatic CRC and are associated with poor outcomes. While many newly diagnosed patients receive FOLFOX (leucovorin/5-FU/oxaliplatin) in the first line, FOLFIRI is a common alternative — often due to concerns about oxaliplatin-associated peripheral neuropathy, Kopetz noted.

The safety lead-in portion of BREAKWATER showed that encorafenib and cetuximab plus FOLFIRI were tolerable and had promising antitumor activity.

Cohort 3 of the trial included 147 patients (mean age, 62 years; 46% male) with BRAF V600E-mutant metastatic CRC, no prior systemic treatment, and good performance status (Eastern Cooperative Oncology Group PS 0 or 1); 73 patients were randomly allocated to encorafenib and cetuximab plus FOLFIRI and 74 to FOLFIRI with or without bevacizumab. The primary endpoint was objective response rate assessed by blinded independent central review.

After a median follow-up of 10 months, patients in the targeted therapy group had an objective response rate of 64.4% vs 39.2% among patients who received FOLFIRI alone or with bevacizumab (odds ratio, 2.76; P = .001).

Responses to the targeted therapies were “rapid and durable,” Kopetz said. More than half (57.4%) of patients treated with encorafenib and cetuximab and FOLFIRI had a duration of response of 6 months or longer than 34.5% in the control group.

Data on overall survival, a secondary endpoint, were not yet mature, but there was a trend toward improved survival with targeted therapy.

Importantly, Kopetz reported, there were no new safety signals, and serious treatment-emergent adverse events occurred at a similar rate in both treatment groups: 39.4% in the targeted therapy group and 36.8% in the control group.

The most common adverse events in both groups included nausea, diarrhea, vomiting, fatigue, appetite loss, and alopecia. About 10% of patients in the targeted therapy group and 9% of those in the control group discontinued their treatment early, suggesting the severity of side effects was similar between the groups.

Kopetz cautioned that the data are still early and follow-up is ongoing. However, he said, the findings support the targeted drugs plus FOLFIRI as a “potential new standard of care” for this patient population.

“The addition of FOLFIRI chemotherapy in the frontline setting will give oncologists and patients more options when selecting a first-line regimen,” Saltzman said. “To have as many options as possible is certainly something we all hope for.”

The trial was funded by Pfizer. Kopetz reported consulting for Pfizer and several other pharmaceutical companies. Saltzman reported having no disclosures.

A version of this article first appeared on Medscape.com.

The targeted therapy combination of encorafenib and cetuximab with FOLFIRI (leucovorin/5-fluorouracil [FU]/irinotecan) chemotherapy may be a new first-line option for patients with BRAF V600E-mutant metastatic colorectal cancer (CRC), according to new results from the BREAKWATER trial.

After a median follow-up of about 10 months, response rates were significantly better with encorafenib and cetuximab plus FOLFIRI than with FOLFIRI alone — without increasing side effects.

The findings, presented at the ASCO Gastrointestinal Cancers Symposium 2026, point to a potential new option for the 20%-25% of patients with BRAF V600E-mutant metastatic CRC who receive FOLFIRI as their chemotherapy.

Based on previous results from BREAKWATER, the FDA granted accelerated approval to first-line encorafenib (Braftovi) and cetuximab (Erbitux) plus mFOLFOX6 for this patient population. That regimen doubled median overall survival compared with standard chemotherapy with or without bevacizumab.

Cohort 3 of BREAKWATER was designed to address a specific question: Are the benefits with the targeted therapy duo a “FOLFOX-specific phenomenon?” lead investigator Scott Kopetz, MD, PhD, of MD Anderson Cancer Center, Houston, said during a press briefing.

Based on these early results, the answer is no. Instead, Kopetz said, there appears to be a “broader synergy” between the targeted therapies and cytotoxic chemotherapy.

Joel Saltzman, MD, ASCO expert in gastrointestinal cancers based at Taussig Cancer Center, Cleveland Clinic in Cleveland, agreed.

“The additional data from the BREAKWATER trial reveals that it is the targeted therapy backbone that provides the better disease control and response rate in BRAF V600E-mutant colorectal cancers,” he said.

BRAF V600E mutations occur in up to 12% of patients with metastatic CRC and are associated with poor outcomes. While many newly diagnosed patients receive FOLFOX (leucovorin/5-FU/oxaliplatin) in the first line, FOLFIRI is a common alternative — often due to concerns about oxaliplatin-associated peripheral neuropathy, Kopetz noted.

The safety lead-in portion of BREAKWATER showed that encorafenib and cetuximab plus FOLFIRI were tolerable and had promising antitumor activity.

Cohort 3 of the trial included 147 patients (mean age, 62 years; 46% male) with BRAF V600E-mutant metastatic CRC, no prior systemic treatment, and good performance status (Eastern Cooperative Oncology Group PS 0 or 1); 73 patients were randomly allocated to encorafenib and cetuximab plus FOLFIRI and 74 to FOLFIRI with or without bevacizumab. The primary endpoint was objective response rate assessed by blinded independent central review.

After a median follow-up of 10 months, patients in the targeted therapy group had an objective response rate of 64.4% vs 39.2% among patients who received FOLFIRI alone or with bevacizumab (odds ratio, 2.76; P = .001).

Responses to the targeted therapies were “rapid and durable,” Kopetz said. More than half (57.4%) of patients treated with encorafenib and cetuximab and FOLFIRI had a duration of response of 6 months or longer than 34.5% in the control group.

Data on overall survival, a secondary endpoint, were not yet mature, but there was a trend toward improved survival with targeted therapy.

Importantly, Kopetz reported, there were no new safety signals, and serious treatment-emergent adverse events occurred at a similar rate in both treatment groups: 39.4% in the targeted therapy group and 36.8% in the control group.

The most common adverse events in both groups included nausea, diarrhea, vomiting, fatigue, appetite loss, and alopecia. About 10% of patients in the targeted therapy group and 9% of those in the control group discontinued their treatment early, suggesting the severity of side effects was similar between the groups.

Kopetz cautioned that the data are still early and follow-up is ongoing. However, he said, the findings support the targeted drugs plus FOLFIRI as a “potential new standard of care” for this patient population.

“The addition of FOLFIRI chemotherapy in the frontline setting will give oncologists and patients more options when selecting a first-line regimen,” Saltzman said. “To have as many options as possible is certainly something we all hope for.”

The trial was funded by Pfizer. Kopetz reported consulting for Pfizer and several other pharmaceutical companies. Saltzman reported having no disclosures.

A version of this article first appeared on Medscape.com.

The targeted therapy combination of encorafenib and cetuximab with FOLFIRI (leucovorin/5-fluorouracil [FU]/irinotecan) chemotherapy may be a new first-line option for patients with BRAF V600E-mutant metastatic colorectal cancer (CRC), according to new results from the BREAKWATER trial.

After a median follow-up of about 10 months, response rates were significantly better with encorafenib and cetuximab plus FOLFIRI than with FOLFIRI alone — without increasing side effects.

The findings, presented at the ASCO Gastrointestinal Cancers Symposium 2026, point to a potential new option for the 20%-25% of patients with BRAF V600E-mutant metastatic CRC who receive FOLFIRI as their chemotherapy.

Based on previous results from BREAKWATER, the FDA granted accelerated approval to first-line encorafenib (Braftovi) and cetuximab (Erbitux) plus mFOLFOX6 for this patient population. That regimen doubled median overall survival compared with standard chemotherapy with or without bevacizumab.

Cohort 3 of BREAKWATER was designed to address a specific question: Are the benefits with the targeted therapy duo a “FOLFOX-specific phenomenon?” lead investigator Scott Kopetz, MD, PhD, of MD Anderson Cancer Center, Houston, said during a press briefing.

Based on these early results, the answer is no. Instead, Kopetz said, there appears to be a “broader synergy” between the targeted therapies and cytotoxic chemotherapy.

Joel Saltzman, MD, ASCO expert in gastrointestinal cancers based at Taussig Cancer Center, Cleveland Clinic in Cleveland, agreed.

“The additional data from the BREAKWATER trial reveals that it is the targeted therapy backbone that provides the better disease control and response rate in BRAF V600E-mutant colorectal cancers,” he said.

BRAF V600E mutations occur in up to 12% of patients with metastatic CRC and are associated with poor outcomes. While many newly diagnosed patients receive FOLFOX (leucovorin/5-FU/oxaliplatin) in the first line, FOLFIRI is a common alternative — often due to concerns about oxaliplatin-associated peripheral neuropathy, Kopetz noted.

The safety lead-in portion of BREAKWATER showed that encorafenib and cetuximab plus FOLFIRI were tolerable and had promising antitumor activity.

Cohort 3 of the trial included 147 patients (mean age, 62 years; 46% male) with BRAF V600E-mutant metastatic CRC, no prior systemic treatment, and good performance status (Eastern Cooperative Oncology Group PS 0 or 1); 73 patients were randomly allocated to encorafenib and cetuximab plus FOLFIRI and 74 to FOLFIRI with or without bevacizumab. The primary endpoint was objective response rate assessed by blinded independent central review.

After a median follow-up of 10 months, patients in the targeted therapy group had an objective response rate of 64.4% vs 39.2% among patients who received FOLFIRI alone or with bevacizumab (odds ratio, 2.76; P = .001).

Responses to the targeted therapies were “rapid and durable,” Kopetz said. More than half (57.4%) of patients treated with encorafenib and cetuximab and FOLFIRI had a duration of response of 6 months or longer than 34.5% in the control group.

Data on overall survival, a secondary endpoint, were not yet mature, but there was a trend toward improved survival with targeted therapy.

Importantly, Kopetz reported, there were no new safety signals, and serious treatment-emergent adverse events occurred at a similar rate in both treatment groups: 39.4% in the targeted therapy group and 36.8% in the control group.

The most common adverse events in both groups included nausea, diarrhea, vomiting, fatigue, appetite loss, and alopecia. About 10% of patients in the targeted therapy group and 9% of those in the control group discontinued their treatment early, suggesting the severity of side effects was similar between the groups.

Kopetz cautioned that the data are still early and follow-up is ongoing. However, he said, the findings support the targeted drugs plus FOLFIRI as a “potential new standard of care” for this patient population.

“The addition of FOLFIRI chemotherapy in the frontline setting will give oncologists and patients more options when selecting a first-line regimen,” Saltzman said. “To have as many options as possible is certainly something we all hope for.”

The trial was funded by Pfizer. Kopetz reported consulting for Pfizer and several other pharmaceutical companies. Saltzman reported having no disclosures.

A version of this article first appeared on Medscape.com.

TOPLINE:

Among patients with ulcerative colitis (UC) who develop colorectal cancer (CRC), greater background mucosal inflammation at the time of CRC diagnosis is associated with progressively worse survival outcomes, with tumors arising within the UC-involved segment having worse prognosis.

METHODOLOGY:

• Patients with UC are at an increased risk for CRC, with risk influenced by the extent and intensity of underlying mucosal inflammation.
• Researchers retrospectively reviewed medical records of patients with UC diagnosed with CRC between 1983 and 2020 at 43 institutions across Japan to determine whether inflammation at cancer diagnosis affected prognosis.
• After endoscopic assessment, tumors were classified as arising inside the UC‑involved segment at diagnosis (within‑area tumors) or outside that segment (outside‑area tumors).
• The Mayo endoscopic score (MES) was used to grade background mucosal inflammation in the within‑area group as inactive (MES 0), mild-moderate (MES 1-2), or severe (MES 3).
• The primary endpoint was 5-year recurrence-free survival, and the secondary endpoint was 5-year cancer-specific survival.

TAKEAWAY:

• Among 723 patients followed for a median of 51 months, 683 had within-area tumors (mean age at CRC diagnosis, 51.8 years; 61.9% male) and 40 had outside-area tumors (mean age at CRC diagnosis, 61.1 years; 60.0% male).
• The within-area group had lower rate of 5-year recurrence-free survival than the outside-area group (75.1% vs 87.6%; P = .022), and lower rate of 5-year cancer-specific survival (81.1% vs 94.3%; P = .038).
• Within-area tumor location independently predicted worse recurrence-free survival (adjusted hazard ratio, 2.99; P = .030).
• In the within‑area group, higher MES was associated with stepwise (although nonsignificant) declines in recurrence‑free survival (inactive, 84.4%; mild-moderate, 79.4%; severe, 73.8%; P = .150). Corresponding cancer‑specific survival rates in these groups declined significantly (89.0%, 84.8%, and 73.8%, respectively; P = .048).

IN PRACTICE:

“These findings shift the clinical focus from inflammation as a risk factor for carcinogenesis to inflammation as a prognostic determinant, highlighting a potential new role for systematic endoscopic assessment of the background mucosa at cancer diagnosis,” the authors wrote.

SOURCE:

This study was led by Akiyoshi Ikebata, Department of Surgery, Keio University School of Medicine, Tokyo, Japan. It was published online in December 2025, in the Journal of Crohn's and Colitis.

LIMITATIONS:

The retrospective design introduced potential for unmeasured confounding and selection bias. The MES was assigned by local physicians without central review, which may have introduced variability. The small size of the outside‑area tumor group increased the risk for baseline imbalances.

DISCLOSURES:

No specific funding source was reported. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

A version of this article first appeared on Medscape.com.

TOPLINE:

Among patients with ulcerative colitis (UC) who develop colorectal cancer (CRC), greater background mucosal inflammation at the time of CRC diagnosis is associated with progressively worse survival outcomes, with tumors arising within the UC-involved segment having worse prognosis.

METHODOLOGY:

• Patients with UC are at an increased risk for CRC, with risk influenced by the extent and intensity of underlying mucosal inflammation.
• Researchers retrospectively reviewed medical records of patients with UC diagnosed with CRC between 1983 and 2020 at 43 institutions across Japan to determine whether inflammation at cancer diagnosis affected prognosis.
• After endoscopic assessment, tumors were classified as arising inside the UC‑involved segment at diagnosis (within‑area tumors) or outside that segment (outside‑area tumors).
• The Mayo endoscopic score (MES) was used to grade background mucosal inflammation in the within‑area group as inactive (MES 0), mild-moderate (MES 1-2), or severe (MES 3).
• The primary endpoint was 5-year recurrence-free survival, and the secondary endpoint was 5-year cancer-specific survival.

TAKEAWAY:

• Among 723 patients followed for a median of 51 months, 683 had within-area tumors (mean age at CRC diagnosis, 51.8 years; 61.9% male) and 40 had outside-area tumors (mean age at CRC diagnosis, 61.1 years; 60.0% male).
• The within-area group had lower rate of 5-year recurrence-free survival than the outside-area group (75.1% vs 87.6%; P = .022), and lower rate of 5-year cancer-specific survival (81.1% vs 94.3%; P = .038).
• Within-area tumor location independently predicted worse recurrence-free survival (adjusted hazard ratio, 2.99; P = .030).
• In the within‑area group, higher MES was associated with stepwise (although nonsignificant) declines in recurrence‑free survival (inactive, 84.4%; mild-moderate, 79.4%; severe, 73.8%; P = .150). Corresponding cancer‑specific survival rates in these groups declined significantly (89.0%, 84.8%, and 73.8%, respectively; P = .048).

IN PRACTICE:

“These findings shift the clinical focus from inflammation as a risk factor for carcinogenesis to inflammation as a prognostic determinant, highlighting a potential new role for systematic endoscopic assessment of the background mucosa at cancer diagnosis,” the authors wrote.

SOURCE:

This study was led by Akiyoshi Ikebata, Department of Surgery, Keio University School of Medicine, Tokyo, Japan. It was published online in December 2025, in the Journal of Crohn's and Colitis.

LIMITATIONS:

The retrospective design introduced potential for unmeasured confounding and selection bias. The MES was assigned by local physicians without central review, which may have introduced variability. The small size of the outside‑area tumor group increased the risk for baseline imbalances.

DISCLOSURES:

No specific funding source was reported. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

A version of this article first appeared on Medscape.com.

TOPLINE:

Among patients with ulcerative colitis (UC) who develop colorectal cancer (CRC), greater background mucosal inflammation at the time of CRC diagnosis is associated with progressively worse survival outcomes, with tumors arising within the UC-involved segment having worse prognosis.

METHODOLOGY:

• Patients with UC are at an increased risk for CRC, with risk influenced by the extent and intensity of underlying mucosal inflammation.
• Researchers retrospectively reviewed medical records of patients with UC diagnosed with CRC between 1983 and 2020 at 43 institutions across Japan to determine whether inflammation at cancer diagnosis affected prognosis.
• After endoscopic assessment, tumors were classified as arising inside the UC‑involved segment at diagnosis (within‑area tumors) or outside that segment (outside‑area tumors).
• The Mayo endoscopic score (MES) was used to grade background mucosal inflammation in the within‑area group as inactive (MES 0), mild-moderate (MES 1-2), or severe (MES 3).
• The primary endpoint was 5-year recurrence-free survival, and the secondary endpoint was 5-year cancer-specific survival.

TAKEAWAY:

• Among 723 patients followed for a median of 51 months, 683 had within-area tumors (mean age at CRC diagnosis, 51.8 years; 61.9% male) and 40 had outside-area tumors (mean age at CRC diagnosis, 61.1 years; 60.0% male).
• The within-area group had lower rate of 5-year recurrence-free survival than the outside-area group (75.1% vs 87.6%; P = .022), and lower rate of 5-year cancer-specific survival (81.1% vs 94.3%; P = .038).
• Within-area tumor location independently predicted worse recurrence-free survival (adjusted hazard ratio, 2.99; P = .030).
• In the within‑area group, higher MES was associated with stepwise (although nonsignificant) declines in recurrence‑free survival (inactive, 84.4%; mild-moderate, 79.4%; severe, 73.8%; P = .150). Corresponding cancer‑specific survival rates in these groups declined significantly (89.0%, 84.8%, and 73.8%, respectively; P = .048).

IN PRACTICE:

“These findings shift the clinical focus from inflammation as a risk factor for carcinogenesis to inflammation as a prognostic determinant, highlighting a potential new role for systematic endoscopic assessment of the background mucosa at cancer diagnosis,” the authors wrote.

SOURCE:

This study was led by Akiyoshi Ikebata, Department of Surgery, Keio University School of Medicine, Tokyo, Japan. It was published online in December 2025, in the Journal of Crohn's and Colitis.

LIMITATIONS:

The retrospective design introduced potential for unmeasured confounding and selection bias. The MES was assigned by local physicians without central review, which may have introduced variability. The small size of the outside‑area tumor group increased the risk for baseline imbalances.

DISCLOSURES:

No specific funding source was reported. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

A version of this article first appeared on Medscape.com.

TOPLINE:

Among patients with high-risk malignant colorectal polyps, 19% had residual disease, with rates of 25% in the immediate surgery group vs 9% in the nonoperative management group. The rate of rectum and sphincter preservation in the nonoperative surveillance group was over 90%, and all recurrences were successfully treated with salvage surgery or chemoradiotherapy.

METHODOLOGY:

• Although guidelines in the US recommend colorectal resection when a malignant colorectal polyp has high-risk features, some patients choose nonoperative management instead to avoid the associated averse effects and impact on quality of life. The safety of nonoperative management, however, remains unclear.
• A single-center cohort study conducted between 2015 and 2022 included 336 patients who underwent polypectomy in the colon (n = 226) or rectum (n = 110) and had at least one high-risk feature. High-risk features included positive margins, piecemeal resection with unclear margin, lymphovascular invasion, perineural invasion, poor differentiation, and tumor budding.
• The analysis compared rates of residual disease between those who had immediate surgery (62%) and nonoperative management (38%) following the removal of a malignant polyp, 15% of whom (n = 19) received systemic chemotherapy after polypectomy.
• Researchers also assessed the rates of distant metastasis between the two groups and the association between specific high-risk features and residual disease or post-treatment complications.

TAKEAWAY:

• In the overall population, 19% of patients had residual disease (63 of 336). Among the 208 patients who had immediate surgery, 25% (n = 51) had residual disease, including 9% (n = 19) with residual disease in the bowel wall and 19% (n = 39) in locoregional lymph nodes. Postoperative complications occurred in 12% of patients (n = 25) in the immediate surgery group, with 3% (n = 7) having complications considered grade 3 or higher.
• Among the 128 patients who received nonoperative surveillance, 9% (n = 12) developed recurrence during surveillance, 6% (n = 7) in the bowel wall and 4% (n = 5) in locoregional lymph nodes. All recurrences in the nonoperative surveillance group were successfully treated with either salvage surgery (n = 6) or chemoradiotherapy (n = 6).
• Among patients in the nonoperative group with a malignant polyp removed from the rectum, the rate of rectum preservation was 94% (74 of 79 patients); the sphincter preservation rate was 91% for tumors < 5 cm from the anal verge.
• Distant metastases occurred in 2% of all patients across both groups.

IN PRACTICE:

"The risk of residual disease after the removal of a malignant colorectal polyp with [high-risk features] is considerable, but nonoperative management offers the potential for organ preservation, with the availability of effective salvage options if rectal cancer is detected," the authors of the study concluded.

SOURCE:

The study, led by Thikhamporn Tawantanakorn, MD, and Martin R. Weiser, MD, of Memorial Sloan Kettering Cancer Center in New York City, was published online in JCO Oncology Advances.

LIMITATIONS:

The researchers noted several limitations, including variable follow-up among patients and challenges in assessing polypectomy histology, particularly after piecemeal resection, which limited evaluation of certain high-risk features such as tumor budding. Additionally, as the study was conducted at a specialized cancer center with dedicated gastrointestinal pathology and radiology services and readily available office endoscopy, the results may not be fully generalizable to less specialized centers.

DISCLOSURES:

Jinru Shia, MD, reported receiving consulting fees from Paige.AI and research funding through their institution. Andrea Cercek, MD, disclosed consulting roles with multiple pharmaceutical companies, including GlaxoSmithKline, Incyte, Merck, and others, as well as research funding from GlaxoSmithKline and Pfizer. Weiser reported receiving royalties as a section editor for UpToDate. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

A version of this article first appeared on Medscape.com.

TOPLINE:

Among patients with high-risk malignant colorectal polyps, 19% had residual disease, with rates of 25% in the immediate surgery group vs 9% in the nonoperative management group. The rate of rectum and sphincter preservation in the nonoperative surveillance group was over 90%, and all recurrences were successfully treated with salvage surgery or chemoradiotherapy.

METHODOLOGY:

• Although guidelines in the US recommend colorectal resection when a malignant colorectal polyp has high-risk features, some patients choose nonoperative management instead to avoid the associated averse effects and impact on quality of life. The safety of nonoperative management, however, remains unclear.
• A single-center cohort study conducted between 2015 and 2022 included 336 patients who underwent polypectomy in the colon (n = 226) or rectum (n = 110) and had at least one high-risk feature. High-risk features included positive margins, piecemeal resection with unclear margin, lymphovascular invasion, perineural invasion, poor differentiation, and tumor budding.
• The analysis compared rates of residual disease between those who had immediate surgery (62%) and nonoperative management (38%) following the removal of a malignant polyp, 15% of whom (n = 19) received systemic chemotherapy after polypectomy.
• Researchers also assessed the rates of distant metastasis between the two groups and the association between specific high-risk features and residual disease or post-treatment complications.

TAKEAWAY:

• In the overall population, 19% of patients had residual disease (63 of 336). Among the 208 patients who had immediate surgery, 25% (n = 51) had residual disease, including 9% (n = 19) with residual disease in the bowel wall and 19% (n = 39) in locoregional lymph nodes. Postoperative complications occurred in 12% of patients (n = 25) in the immediate surgery group, with 3% (n = 7) having complications considered grade 3 or higher.
• Among the 128 patients who received nonoperative surveillance, 9% (n = 12) developed recurrence during surveillance, 6% (n = 7) in the bowel wall and 4% (n = 5) in locoregional lymph nodes. All recurrences in the nonoperative surveillance group were successfully treated with either salvage surgery (n = 6) or chemoradiotherapy (n = 6).
• Among patients in the nonoperative group with a malignant polyp removed from the rectum, the rate of rectum preservation was 94% (74 of 79 patients); the sphincter preservation rate was 91% for tumors < 5 cm from the anal verge.
• Distant metastases occurred in 2% of all patients across both groups.

IN PRACTICE:

"The risk of residual disease after the removal of a malignant colorectal polyp with [high-risk features] is considerable, but nonoperative management offers the potential for organ preservation, with the availability of effective salvage options if rectal cancer is detected," the authors of the study concluded.

SOURCE:

The study, led by Thikhamporn Tawantanakorn, MD, and Martin R. Weiser, MD, of Memorial Sloan Kettering Cancer Center in New York City, was published online in JCO Oncology Advances.

LIMITATIONS:

The researchers noted several limitations, including variable follow-up among patients and challenges in assessing polypectomy histology, particularly after piecemeal resection, which limited evaluation of certain high-risk features such as tumor budding. Additionally, as the study was conducted at a specialized cancer center with dedicated gastrointestinal pathology and radiology services and readily available office endoscopy, the results may not be fully generalizable to less specialized centers.

DISCLOSURES:

Jinru Shia, MD, reported receiving consulting fees from Paige.AI and research funding through their institution. Andrea Cercek, MD, disclosed consulting roles with multiple pharmaceutical companies, including GlaxoSmithKline, Incyte, Merck, and others, as well as research funding from GlaxoSmithKline and Pfizer. Weiser reported receiving royalties as a section editor for UpToDate. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

A version of this article first appeared on Medscape.com.

TOPLINE:

Among patients with high-risk malignant colorectal polyps, 19% had residual disease, with rates of 25% in the immediate surgery group vs 9% in the nonoperative management group. The rate of rectum and sphincter preservation in the nonoperative surveillance group was over 90%, and all recurrences were successfully treated with salvage surgery or chemoradiotherapy.

METHODOLOGY:

• Although guidelines in the US recommend colorectal resection when a malignant colorectal polyp has high-risk features, some patients choose nonoperative management instead to avoid the associated averse effects and impact on quality of life. The safety of nonoperative management, however, remains unclear.
• A single-center cohort study conducted between 2015 and 2022 included 336 patients who underwent polypectomy in the colon (n = 226) or rectum (n = 110) and had at least one high-risk feature. High-risk features included positive margins, piecemeal resection with unclear margin, lymphovascular invasion, perineural invasion, poor differentiation, and tumor budding.
• The analysis compared rates of residual disease between those who had immediate surgery (62%) and nonoperative management (38%) following the removal of a malignant polyp, 15% of whom (n = 19) received systemic chemotherapy after polypectomy.
• Researchers also assessed the rates of distant metastasis between the two groups and the association between specific high-risk features and residual disease or post-treatment complications.

TAKEAWAY:

• In the overall population, 19% of patients had residual disease (63 of 336). Among the 208 patients who had immediate surgery, 25% (n = 51) had residual disease, including 9% (n = 19) with residual disease in the bowel wall and 19% (n = 39) in locoregional lymph nodes. Postoperative complications occurred in 12% of patients (n = 25) in the immediate surgery group, with 3% (n = 7) having complications considered grade 3 or higher.
• Among the 128 patients who received nonoperative surveillance, 9% (n = 12) developed recurrence during surveillance, 6% (n = 7) in the bowel wall and 4% (n = 5) in locoregional lymph nodes. All recurrences in the nonoperative surveillance group were successfully treated with either salvage surgery (n = 6) or chemoradiotherapy (n = 6).
• Among patients in the nonoperative group with a malignant polyp removed from the rectum, the rate of rectum preservation was 94% (74 of 79 patients); the sphincter preservation rate was 91% for tumors < 5 cm from the anal verge.
• Distant metastases occurred in 2% of all patients across both groups.

IN PRACTICE:

"The risk of residual disease after the removal of a malignant colorectal polyp with [high-risk features] is considerable, but nonoperative management offers the potential for organ preservation, with the availability of effective salvage options if rectal cancer is detected," the authors of the study concluded.

SOURCE:

The study, led by Thikhamporn Tawantanakorn, MD, and Martin R. Weiser, MD, of Memorial Sloan Kettering Cancer Center in New York City, was published online in JCO Oncology Advances.

LIMITATIONS:

The researchers noted several limitations, including variable follow-up among patients and challenges in assessing polypectomy histology, particularly after piecemeal resection, which limited evaluation of certain high-risk features such as tumor budding. Additionally, as the study was conducted at a specialized cancer center with dedicated gastrointestinal pathology and radiology services and readily available office endoscopy, the results may not be fully generalizable to less specialized centers.

DISCLOSURES:

Jinru Shia, MD, reported receiving consulting fees from Paige.AI and research funding through their institution. Andrea Cercek, MD, disclosed consulting roles with multiple pharmaceutical companies, including GlaxoSmithKline, Incyte, Merck, and others, as well as research funding from GlaxoSmithKline and Pfizer. Weiser reported receiving royalties as a section editor for UpToDate. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.

A version of this article first appeared on Medscape.com.

Intensive long-distance running could be a risk for advanced adenomas (AAs) for the colon, a small prospective study reported this summer at the American Society of Clinical Oncology (ASCO) 2025.

Refined screening strategies for this running population are therefore warranted, and pathologic and epidemiologic evaluations should explore causation and ancillary risk factors in this unique population, according to Timothy L. Cannon, MD, oncologist at Inova Schar Cancer Institute in Fairfax, Virginia, and colleagues.

The full study (NCT 05419531), which is currently being reviewed for publication, looked at colonoscopy results from 100 marathon and ultramarathon runners and found that almost half had polyps, and 15% (95% CI, 7.9-22.4) had confirmed AAs).

The AA rate was higher than the 4.5% to 6% seen in adults in their late 40s in the general population and was higher even than the 12% found in Alaska Natives, who are at heightened risk for colon cancer.

"After meeting 3 extreme endurance athletes — 2 who ran 100-mile ultramarathons and 1 lady who ran dozens of triathlons — with stage IV colon cancer before age 40, I began to be suspicious of a link," Cannon told Medscape Medical News. At least 2 of them said they were told that bleeding after long runs was common, which they took to mean as normal. "I could imagine multiple reasons that endurance runners would be predisposed to cancer, with my initial focus on the inflammation and cell turnover incited by the well-described ischemia and runner's colitis."

Study Details

From October 2022 to December 2024, 100 eligible participants aged 35 to 50 years had colonoscopies. The median age was 42.5 years; 55 participants were female and 45 were male. In terms of endurance eligibility, all had completed at ≥ 2 registered ultramarathons (50 km or longer) or 5 registered marathons (26.2 miles). Patients were excluded if they were known or suspected to have inflammatory bowel disease, familial adenomatous polyposis, or Lynch syndrome (hereditary nonpolyposis colorectal cancer).

The historical 1.2% in average-risk individuals aged 40-49 years was used for the expected rate of AAs, defined as lesions > 10 mm, lesions with 25% tubulovillous features, or high-grade dysplasia.

In other findings, 39 had ≥ 1 adenoma and had ≥ 3 adenomas but did not meet AA criteria and were not included in the 15% with AA.

While no colon cancer was detected in the cohort, Cannon said 30% experienced rectal bleeding after exercise, especially those with AAs compared with those without: 53% vs 22%. "While rectal bleeding had a significant association with finding advanced adenomas on the colonoscopy, there were still many with advanced adenomas who reported no bleeding," he said.

Runner's colitis, or trots, is a common condition thought to be related to ischemia, mechanical stress, or adverse impact on the gut microbiome. "Mechanism is the huge question that I certainly can't answer at this point," Cannon said. "At some distance, blood flow gets diverted from the splanchnic circulation to the legs, and gut ischemia seems to ensue. I envision high rates of disorderly cell turnover and more opportunities for mutagenesis. This needs to be studied, and what I am describing is certainly either an oversimplification or simply not related at all."

The authors noted that exercise-induced gastrointestinal injury is likely associated with reduced blood flow to the intestines during long-distance running, but not evidence has linked this bowel ischemia to carcinogenesis.

Diet could be another factor. "I am fascinated with runners' diets. They seem to consume, on average, a huge amount of ultraprocessed bars and goos. They also may drink from plastic bottles far more than the average person. These are just 2 of many possibilities," Cannon said. "Nearly a third of our participants were vegan or vegetarian. We are planning a second, more detailed, survey or our participants. We will really dig down on these questions as well as specifics regarding their training regimens."

Commenting on the study but not involved in it, Thomas F. Imperiale, MD, professor of gastroenterology and hepatology at Indiana University Indianapolis, said that while the findings are provocative, several methodological issues require consideration in subsequent research.

"First, the comparative benchmark of advanced adenoma prevalence of 1.2% is based on screening colonoscopy data from 25 years ago. At the very least, a concurrent benchmark should be used," he told Medscape Medical News. The second issue is the absence of a control group of persons who may exercise but who do not run marathons. "This addition would strengthen study validity more than using a concurrent comparison."

The case group of long-distance runners and a control group of nonmarathon runners could be compared for prevalence of AAs with adjustment for age, sex, race or ethnicity, family history of colorectal cancer, diet, other physical activity, tobacco use history, BMI or waist circumference, ethanol use, and perhaps other early-life exposures and indication for colonoscopy. "Last, it would be interesting to know whether and how often the 100 participants developed symptoms possibly consistent with colonic ischemia either during or after long-distance runs, which might provide indirect support for the presumptive mechanism of action."

In other comments, Hamed Khalili, MD, MPH, gastroenterologist at Massachusetts General Hospital and associate professor at Harvard Medical School, both in Boston, called the results very preliminary. "The sample size is small, and the comparator group is a historical control, so it's unclear whether the observed differences are just a sampling issue," he said.

Cannon has this advice for physicians: "Please don't dismiss symptoms of runner's colitis as benign. This condition requires investigation," he said. While he hasn't seen any expert recommendation to treat postrunning bleeding any differently from other causes of melena or hematochezia, both of which would normally merit a colonoscopy, in practice many gastroenterologists dismiss this type of bleeding as benign. "If larger studies confirm our findings, I don't think it's out of the question that marathoners will have unique screening recommendations. But this study is not robust enough, of course, to merit such a recommendation."

His group is planning a study on the runner's microbiome and on the proteome of the colonic tissue in this group.

Cannon reported having no relevant conflicts of interest to disclose. Imperiale and Khalili reported having no conflicts of interest relevant to their comments on the study.

A version of this article first appeared on Medscape.com.

Intensive long-distance running could be a risk for advanced adenomas (AAs) for the colon, a small prospective study reported this summer at the American Society of Clinical Oncology (ASCO) 2025.

Refined screening strategies for this running population are therefore warranted, and pathologic and epidemiologic evaluations should explore causation and ancillary risk factors in this unique population, according to Timothy L. Cannon, MD, oncologist at Inova Schar Cancer Institute in Fairfax, Virginia, and colleagues.

The full study (NCT 05419531), which is currently being reviewed for publication, looked at colonoscopy results from 100 marathon and ultramarathon runners and found that almost half had polyps, and 15% (95% CI, 7.9-22.4) had confirmed AAs).

The AA rate was higher than the 4.5% to 6% seen in adults in their late 40s in the general population and was higher even than the 12% found in Alaska Natives, who are at heightened risk for colon cancer.

"After meeting 3 extreme endurance athletes — 2 who ran 100-mile ultramarathons and 1 lady who ran dozens of triathlons — with stage IV colon cancer before age 40, I began to be suspicious of a link," Cannon told Medscape Medical News. At least 2 of them said they were told that bleeding after long runs was common, which they took to mean as normal. "I could imagine multiple reasons that endurance runners would be predisposed to cancer, with my initial focus on the inflammation and cell turnover incited by the well-described ischemia and runner's colitis."

Study Details

From October 2022 to December 2024, 100 eligible participants aged 35 to 50 years had colonoscopies. The median age was 42.5 years; 55 participants were female and 45 were male. In terms of endurance eligibility, all had completed at ≥ 2 registered ultramarathons (50 km or longer) or 5 registered marathons (26.2 miles). Patients were excluded if they were known or suspected to have inflammatory bowel disease, familial adenomatous polyposis, or Lynch syndrome (hereditary nonpolyposis colorectal cancer).

The historical 1.2% in average-risk individuals aged 40-49 years was used for the expected rate of AAs, defined as lesions > 10 mm, lesions with 25% tubulovillous features, or high-grade dysplasia.

In other findings, 39 had ≥ 1 adenoma and had ≥ 3 adenomas but did not meet AA criteria and were not included in the 15% with AA.

While no colon cancer was detected in the cohort, Cannon said 30% experienced rectal bleeding after exercise, especially those with AAs compared with those without: 53% vs 22%. "While rectal bleeding had a significant association with finding advanced adenomas on the colonoscopy, there were still many with advanced adenomas who reported no bleeding," he said.

Runner's colitis, or trots, is a common condition thought to be related to ischemia, mechanical stress, or adverse impact on the gut microbiome. "Mechanism is the huge question that I certainly can't answer at this point," Cannon said. "At some distance, blood flow gets diverted from the splanchnic circulation to the legs, and gut ischemia seems to ensue. I envision high rates of disorderly cell turnover and more opportunities for mutagenesis. This needs to be studied, and what I am describing is certainly either an oversimplification or simply not related at all."

The authors noted that exercise-induced gastrointestinal injury is likely associated with reduced blood flow to the intestines during long-distance running, but not evidence has linked this bowel ischemia to carcinogenesis.

Diet could be another factor. "I am fascinated with runners' diets. They seem to consume, on average, a huge amount of ultraprocessed bars and goos. They also may drink from plastic bottles far more than the average person. These are just 2 of many possibilities," Cannon said. "Nearly a third of our participants were vegan or vegetarian. We are planning a second, more detailed, survey or our participants. We will really dig down on these questions as well as specifics regarding their training regimens."

Commenting on the study but not involved in it, Thomas F. Imperiale, MD, professor of gastroenterology and hepatology at Indiana University Indianapolis, said that while the findings are provocative, several methodological issues require consideration in subsequent research.

"First, the comparative benchmark of advanced adenoma prevalence of 1.2% is based on screening colonoscopy data from 25 years ago. At the very least, a concurrent benchmark should be used," he told Medscape Medical News. The second issue is the absence of a control group of persons who may exercise but who do not run marathons. "This addition would strengthen study validity more than using a concurrent comparison."

The case group of long-distance runners and a control group of nonmarathon runners could be compared for prevalence of AAs with adjustment for age, sex, race or ethnicity, family history of colorectal cancer, diet, other physical activity, tobacco use history, BMI or waist circumference, ethanol use, and perhaps other early-life exposures and indication for colonoscopy. "Last, it would be interesting to know whether and how often the 100 participants developed symptoms possibly consistent with colonic ischemia either during or after long-distance runs, which might provide indirect support for the presumptive mechanism of action."

In other comments, Hamed Khalili, MD, MPH, gastroenterologist at Massachusetts General Hospital and associate professor at Harvard Medical School, both in Boston, called the results very preliminary. "The sample size is small, and the comparator group is a historical control, so it's unclear whether the observed differences are just a sampling issue," he said.

Cannon has this advice for physicians: "Please don't dismiss symptoms of runner's colitis as benign. This condition requires investigation," he said. While he hasn't seen any expert recommendation to treat postrunning bleeding any differently from other causes of melena or hematochezia, both of which would normally merit a colonoscopy, in practice many gastroenterologists dismiss this type of bleeding as benign. "If larger studies confirm our findings, I don't think it's out of the question that marathoners will have unique screening recommendations. But this study is not robust enough, of course, to merit such a recommendation."

His group is planning a study on the runner's microbiome and on the proteome of the colonic tissue in this group.

Cannon reported having no relevant conflicts of interest to disclose. Imperiale and Khalili reported having no conflicts of interest relevant to their comments on the study.

A version of this article first appeared on Medscape.com.

Intensive long-distance running could be a risk for advanced adenomas (AAs) for the colon, a small prospective study reported this summer at the American Society of Clinical Oncology (ASCO) 2025.

Refined screening strategies for this running population are therefore warranted, and pathologic and epidemiologic evaluations should explore causation and ancillary risk factors in this unique population, according to Timothy L. Cannon, MD, oncologist at Inova Schar Cancer Institute in Fairfax, Virginia, and colleagues.

The full study (NCT 05419531), which is currently being reviewed for publication, looked at colonoscopy results from 100 marathon and ultramarathon runners and found that almost half had polyps, and 15% (95% CI, 7.9-22.4) had confirmed AAs).

The AA rate was higher than the 4.5% to 6% seen in adults in their late 40s in the general population and was higher even than the 12% found in Alaska Natives, who are at heightened risk for colon cancer.

"After meeting 3 extreme endurance athletes — 2 who ran 100-mile ultramarathons and 1 lady who ran dozens of triathlons — with stage IV colon cancer before age 40, I began to be suspicious of a link," Cannon told Medscape Medical News. At least 2 of them said they were told that bleeding after long runs was common, which they took to mean as normal. "I could imagine multiple reasons that endurance runners would be predisposed to cancer, with my initial focus on the inflammation and cell turnover incited by the well-described ischemia and runner's colitis."

Study Details

From October 2022 to December 2024, 100 eligible participants aged 35 to 50 years had colonoscopies. The median age was 42.5 years; 55 participants were female and 45 were male. In terms of endurance eligibility, all had completed at ≥ 2 registered ultramarathons (50 km or longer) or 5 registered marathons (26.2 miles). Patients were excluded if they were known or suspected to have inflammatory bowel disease, familial adenomatous polyposis, or Lynch syndrome (hereditary nonpolyposis colorectal cancer).

The historical 1.2% in average-risk individuals aged 40-49 years was used for the expected rate of AAs, defined as lesions > 10 mm, lesions with 25% tubulovillous features, or high-grade dysplasia.

In other findings, 39 had ≥ 1 adenoma and had ≥ 3 adenomas but did not meet AA criteria and were not included in the 15% with AA.

While no colon cancer was detected in the cohort, Cannon said 30% experienced rectal bleeding after exercise, especially those with AAs compared with those without: 53% vs 22%. "While rectal bleeding had a significant association with finding advanced adenomas on the colonoscopy, there were still many with advanced adenomas who reported no bleeding," he said.

Runner's colitis, or trots, is a common condition thought to be related to ischemia, mechanical stress, or adverse impact on the gut microbiome. "Mechanism is the huge question that I certainly can't answer at this point," Cannon said. "At some distance, blood flow gets diverted from the splanchnic circulation to the legs, and gut ischemia seems to ensue. I envision high rates of disorderly cell turnover and more opportunities for mutagenesis. This needs to be studied, and what I am describing is certainly either an oversimplification or simply not related at all."

The authors noted that exercise-induced gastrointestinal injury is likely associated with reduced blood flow to the intestines during long-distance running, but not evidence has linked this bowel ischemia to carcinogenesis.

Diet could be another factor. "I am fascinated with runners' diets. They seem to consume, on average, a huge amount of ultraprocessed bars and goos. They also may drink from plastic bottles far more than the average person. These are just 2 of many possibilities," Cannon said. "Nearly a third of our participants were vegan or vegetarian. We are planning a second, more detailed, survey or our participants. We will really dig down on these questions as well as specifics regarding their training regimens."

Commenting on the study but not involved in it, Thomas F. Imperiale, MD, professor of gastroenterology and hepatology at Indiana University Indianapolis, said that while the findings are provocative, several methodological issues require consideration in subsequent research.

"First, the comparative benchmark of advanced adenoma prevalence of 1.2% is based on screening colonoscopy data from 25 years ago. At the very least, a concurrent benchmark should be used," he told Medscape Medical News. The second issue is the absence of a control group of persons who may exercise but who do not run marathons. "This addition would strengthen study validity more than using a concurrent comparison."

The case group of long-distance runners and a control group of nonmarathon runners could be compared for prevalence of AAs with adjustment for age, sex, race or ethnicity, family history of colorectal cancer, diet, other physical activity, tobacco use history, BMI or waist circumference, ethanol use, and perhaps other early-life exposures and indication for colonoscopy. "Last, it would be interesting to know whether and how often the 100 participants developed symptoms possibly consistent with colonic ischemia either during or after long-distance runs, which might provide indirect support for the presumptive mechanism of action."

In other comments, Hamed Khalili, MD, MPH, gastroenterologist at Massachusetts General Hospital and associate professor at Harvard Medical School, both in Boston, called the results very preliminary. "The sample size is small, and the comparator group is a historical control, so it's unclear whether the observed differences are just a sampling issue," he said.

Cannon has this advice for physicians: "Please don't dismiss symptoms of runner's colitis as benign. This condition requires investigation," he said. While he hasn't seen any expert recommendation to treat postrunning bleeding any differently from other causes of melena or hematochezia, both of which would normally merit a colonoscopy, in practice many gastroenterologists dismiss this type of bleeding as benign. "If larger studies confirm our findings, I don't think it's out of the question that marathoners will have unique screening recommendations. But this study is not robust enough, of course, to merit such a recommendation."

His group is planning a study on the runner's microbiome and on the proteome of the colonic tissue in this group.

Cannon reported having no relevant conflicts of interest to disclose. Imperiale and Khalili reported having no conflicts of interest relevant to their comments on the study.

A version of this article first appeared on Medscape.com.