Risk of pre-cancerous advanced adenomas of the colon in long distance runners.

Abstract

3619 Background: Exercise induced gastrointestinal injury is believed to be associated with reduced blood flow to the intestines during long distance running. To our knowledge, there has not been evidence linking this type of exercise- induced bowel ischemia to carcinogenesis. After observing multiple “ultramarathoners” present to our cancer center with advanced colorectal cancer, we initiated a prospective IRB-approved study to evaluate the risk of advanced adenomas (AA) in long distance runners between the ages of 35-50. Methods: NCT 05419531 was a prospective study of subjects aged 35-50 years who had completed at least two registered ultramarathons (50 km or longer) or five registered marathons (26.2 miles). Subjects were excluded if they were known or suspected to have inflammatory bowel disease, familial adenomatous polyposis (FAP), or Lynch Syndrome. Prior to colonoscopy, each subject completed a questionnaire regarding dietary habits, bowel habits, and long-distance running history, with results to be reported in the future. All polyps discovered during colonoscopy were reviewed by a panel of gastroenterologists, pathologists, and oncologists to determine if they met the criteria for advanced adenomas, defined as lesions >10 mm, >25% tubulovillous features, or high-grade dysplasia. Results: Between October 2022 and December 2024, 102 subjects were screened, and 100 underwent colonoscopy as part of the study. The median age was 42.5 years; 55 of the participants were female and 45 were male. The historical benchmark used for expected AAs in average-risk individuals aged 40-49 years was 1.2%. Among the 100 subjects in this study, 15% (95% exact confidence interval: 7.9%- 22.4%) had confirmed AAs. 39 out of 100 subjects had at least one adenoma. Three additional subjects had three or more adenomas but did not meet our predefined criteria for AA and were not included among the 15 patients with AA. Conclusions: NCT 05419531 achieved its predefined endpoint for advanced adenomas, suggesting that “intensive” long distance running is a risk factor for advanced adenomas of the colon. Consideration of refined screening strategies for this population is warranted. Future pathological and epidemiological evaluations should explore causation and ancillary risk factors in this unique population. Clinical trial information: NCT05419531 . Subjects with advanced adenoma. Participant ID 3 9 15 16 37 53 55 67 69 71 77 87 91 98 100 Gender F M M F F M F F F F F M M F M Age 44 45 48 41 45 49 40 40 45 39 42 50 42 44 41 Endurance Eligibility (U – Ultramarathons; M – Marathons) 4 - 6 U 4 - 6 U > 15 U 4 - 6 U > 15 U 7 - 15 U 6 M 5 M 7 - 15 U 1 U / 7-8 M > 15 U > 15 U 10 M > 15 U 5 M # of Polyps 3 on primary; 2 on secondary 5 2 3 1 1 3 2 7 1 2 4 2 6 3 Size of largest polyp (Colonoscopy/Pathology) (mm) 25 / 15 12 / 15 10 / 13 10 / 10 3 / 3 20 / 9 5-6 / 5 12/11 12 / 12 5 / 5 5 / 5 15-20 / 12 6 / 7 10 / 7 10 / 19 >25% Tubulovillous Features (Y/N) N N N N Y N Y N N Y Y N N Y N High-grade Dysplasia (Y/N) N N N N N N N N N N N N Y N N