By Alicia H. Muratore, MD, MBA

Like many of you, I've been following the media coverage of a recent abstract presentation suggesting higher rates of polyps and advanced adenomas among marathon and ultramarathon runners. The headline “Are Marathons and Extreme Running Linked to Colon Cancer?” was attention-grabbing. Since the article published, I have received a flurry of texts and emails from fellow runners asking me, “Should I be worried?”

I'm a gastroenterologist and recent graduate from the fellowship at the University of North Carolina.

This study hits close to home for me. Outside the endoscopy suite, I have run 14 marathons since 2016, and even a 30-mile ultradistance run. Running is a huge part of my life. When headlines suggest a possible connection between extreme endurance running and colorectal cancer, I pay attention — not just as a gastroenterologist, but as part of the running community that feels implicated.

What has the study actually found? The ASCO abstract reported that 39% of long-distance runners aged 30-50 had at least one polyp, and 15% had advanced adenomas compared to historical controls of 1.2%. That's a striking number.

The context matters. This was an abstract presentation. There was not a matched control group of nonrunners. We don't yet know whether unmeasured lifestyle or dietary factors could explain part of the difference. While patients with suspected inflammatory bowel disease, familial adenoma, ptosis, polyposis, or Lynch syndrome were excluded, other family history of colorectal cancer was not yet reported.

Other current medical literature consistently suggests that regular physical activity, including running, reduces colorectal cancer risk, whereas sedentary behavior is a recognized risk factor, especially in early-onset disease.

Additionally, other large-scale meta-analyses show running is associated with lower cancer mortality, with no evidence that higher doses of running confer additional risk. It's an intriguing signal but not yet practice-changing evidence.

Why is it worth talking about? Even if causality isn't established, the study touches a nerve because we already know colorectal cancer is rising among younger adults. Incidence of early-onset colorectal cancer is climbing at approximately 2%-3% per year in the US. By 2030, colorectal cancer is projected to become the leading cause of cancer death in people under 50.

Whether you're a runner or not, the broader message is the same: Younger people are facing a rising colorectal cancer risk and vigilance is key.

How does this affect clinical practice? For us in gastroenterology, here's what I tell my patients and my fellow runners: One, this doesn't change current screening guidelines. Average-risk adults should begin screening at 45. High-risk patients still need earlier, tailored strategies.

Two: Symptoms matter. Blood in the stool, new changes in bowel habits, and unexplained anemia should never be dismissed as just hemorrhoids or just training fatigue. These symptoms warrant a discussion and an evaluation with a physician.

Three: Running itself remains beneficial. Regular moderate exercise reduces the risk for multiple cancers, including colorectal cancer.Extreme training might introduce unique physiologic stressors, but the evidence is far from conclusive.

Four: Screening saves lives. Colonoscopy with adenoma removal can reduce colorectal cancer mortality. For a population that's disciplined enough to run marathons, adherence to screening is an achievable and life-saving goal.

Here’s my takeaway as both a runner and a gastroenterologist, as someone who's trained for marathons while on fellowship call weeks. I understand the lifestyle, the passion, and the identity tied to running. I also understand the anxiety that this kind of study can stir up in a community that prizes health.

My advice to patients and to running partners alike: Lace up, keep running, but don't outrun your colon health. Screening saves lives, and paying attention to symptoms matters more than your weekly mileage.

As for us gastroenterologists, let's use this media moment to engage our patients, including athletes, in conversations about colorectal cancer risk, symptom awareness, and the proven power of prevention.