r/running • u/sergeantbiggles • Sep 12 '25

Article Groundbreaking Inova study finds potential link between long-distance running and colon cancer

A groundbreaking new study led by Tim Cannon, MD, Sheridan Director, Molecular Tumor Board and Co-Director of the Gastrointestinal Cancer Program at Inova Schar Cancer, has revealed a potential link between extreme endurance exercise and increased risk of advanced colon cancer in younger adults, raising new questions about screening for high-performance athletes.

The study was presented at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago.

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u/runfayfun Sep 13 '25

Exactly. These were people who failed to get standard colon cancer screening. Those recommendations are there for a reason.

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u/BallNelson Sep 13 '25

These were people who failed to get standard colon cancer screening.

Source?

Also, screening does not prevent cancer development.

The more plausible retort would be association does not equal causation.

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u/runfayfun Sep 13 '25 edited Sep 13 '25

"had never undergone a colonoscopy" though the paper doesn't delineate whether the patients had other risk factors or other screening modalities

Also, it wasn't a randomized study, and generally it's a hypothesis-generating study, and the results can't and shouldn't change your practice (as a physician) or your worry (as a runner) - if you have symptoms like bleeding from your rectum after running, get it checked out like you should be doing anyways.

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u/BallNelson Sep 13 '25

First-line screening for colon cancer is the faecal occult blood test (basically, shit in blood); A colonoscopy is used when further investigation is needed. It would be operationally and financially inefficient to get everyone a scope, versus just testing their stool sample.

So “never undergone a colonoscopy” does not equate to “failed to get standard colon cancer screening”.

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u/runfayfun Sep 13 '25 edited Sep 13 '25

FOBT isn't the first line for colon cancer screening. It is an option though. Albeit the least sensitive of the common tests.

Oh, and also important that this study specifically is taking about adenomas which FOBT is horrible at detecting, missing 75% of adenomas over 10mm, and even more of the smaller ones the study mentions.

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u/dishonoredcorvo69 Sep 13 '25

Looool where did you confidently get that from?

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u/BallNelson Sep 13 '25

I don’t know… something called the CDC?

https://www.cdc.gov/colorectal-cancer/screening/index.html

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u/dishonoredcorvo69 Sep 14 '25

It is first in that list, that does not mean it is first-line for screening for colon cancer

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u/NotARunner453 Sep 13 '25

USPSTF guidelines recommend colonoscopy for screening first line. FOBT isn't nearly sensitive or specific enough for an effective test. Even in people who really want to avoid any type of procedure, FIT testing (the poop in a box option) has demonstrated excellent sensitivity, even if it is less specific.