Adults under 50 undergoing colonoscopy were found to have a dramatically higher risk of having colorectal cancer when the procedure was done for rectal bleeding. Researchers found that rectal bleeding increased the odds of a colorectal cancer diagnosis by 8.5 times, underscoring the need to take the symptom seriously even in the absence of a family history in a population who may not otherwise meet screening age criteria.\u00a0<\/p>\n
The research will be presented at the American College of Surgeons (ACS) Clinical Congress 2025 in Chicago, October 4-7.\u00a0<\/p>\n
The retrospective study analyzed 443 patients under 50 who underwent a colonoscopy at the University of Louisville Health System between 2021 and 2023. Of them, 195 (44%) were diagnosed with early-onset colorectal cancer, while 248 (56%) had normal results.\u00a0<\/p>\n
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Many of the early-onset colorectal cancers that I see have no family history. This research lends support to the question of who does or doesn’t warrant a colonoscopy: if you have a person below the screening age with rectal bleeding, you should seriously consider a colonoscopy.”\u00a0<\/p>\n
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Sandra Kavalukas, MD, FACS, senior author, colorectal surgeon, University of Louisville School of Medicine in Louisville, Kentucky<\/p>\n
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Key findings\u00a0\u00a0<\/p>\n
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Symptom-driven care: The vast majority (88%) of patients later diagnosed with early-onset colorectal cancer underwent colonoscopy due to symptoms, such as bleeding, compared to just over half (55%) of non-cancer patients.\u00a0<\/p>\n
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Limited role of genetics: Only 13% of early-onset colorectal cancer cases had a marker often associated with hereditary syndromes, such as genetic alterations that occur in some colorectal cancers. A family history of colorectal cancer, while a factor, was only associated with a two-fold increase in odds.\u00a0<\/p>\n
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The study aims to help clinicians decide which young, symptomatic patients would benefit from undergoing a diagnostic colonoscopy.\u00a0<\/p>\n
“If they’re 35 and they come in with rectal pain, they probably don’t need a colonoscopy,” Dr. Kavalukas explained. “But if they come in with a bleeding complaint, they are 8.5 times more likely to have a colorectal cancer.”\u00a0<\/p>\n
The findings address a critical gap in care for young adults, who are not eligible for routine screening but are experiencing the fastest-rising rates of colorectal cancer. The study provides data to support coverage for diagnostic colonoscopies in symptomatic young patients.\u00a0<\/p>\n
The U.S. Preventive Services Task Force guidelines recommend screening colonoscopies starting at age 45 for most people without a family history of the disease.\u00a0<\/p>\n
The research team is now working on a larger analysis with the goal of creating a risk score calculator.\u00a0<\/p>\n
Co-authors are Allie Jin, BA; Jeremy Gaskins, PhD; Ramsey Amoudi, BS; Marcus Bennett, BA; Kailyn Deitz, BS; Caroline Hourigan, BS; and Natalie DuPre, ScD.\u00a0<\/p>\n
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