It is an activity loved by concerned about health, but long distance race could increase the risk of colon cancer among young people.
A study revealed that 35 to 50 years which regularly run marathons are more likely to develop precancerous tumors in their colon, precursors of the disease.
Of the 100 patients studied by DC scientists, 41% proved to have at least one adenoma – a benign tumor that could turn into cancer.
Fifteen percent had advanced adenomas, or more advanced growth. Among these people, more than half have reportedly reported from rectal bleeding, a sign of cancer warning.
Dr. Timothy Cannon, the medical oncologist who directed research, told Dailymail.com that the results were higher than the doctors would expect in the general population and justified a more in -depth investigation.
He said that all long-distance runners with colon cancer warning signs, such as rectal bleeding, should be tested for illness, whatever their age.
The study was observational, it is therefore not clear if the distance distance increases the risk of if other lifestyle factors such as the diet play a role.
But Dr. Cannon suggested that it could be because the long period race causes the blood of from the colon to the legs, which increases the risk of cellular death and damaging mutations.
The colon cancer patient was shown above, Phil Decker in January 2025, illustrated to run a marathon with Alecia Allen. He was preparing to run a marathon when he received a diagnosis of stadium colon cancer
Radwah Oda never thought she could get cancer because we were in “excellent health” at the time of her diagnosis at 33 years old. She trained five times a week
He said: ‘As acologist of colon cancer, I had seen several patients die of colon cancer who was in the thirties who ran ultramarathons, which were 50 km or more.
“We did this study because we fear that these runners do not entertain their entire blood flow to their legs during the races.
“And (then have) infarctions in their colon, and a lot of cell rolling; The cells die and then turn around very quickly (meaning) there may be more risk of cancer causing mutations.
The infarctions are an area of dead fabric caused by a loss of blood supply. When the blood flow is blocked or seriously reduced – generally by a clot, embolism or shrinking vessels – affected tissues do not receive oxygen and nutrients it needs, and it dies.
This is just the last explanation put forward by scientists to explain the push of colon cancer cases in those under 50With those born in the 1980s now having double the risk of being diagnosed with cancer compared to their parents.
It is not clear if long -distance running can also be linked to a higher risk of other cancers that increase in young people, as in the pancreas.
Many young patients with colon cancer were shocked by their diagnosisSaying that they are young, healthy and – they thought – did everything correctly.
Patients include Laurie Koshers, a vegetarian who was running every day, but was diagnosed with colon cancer at 44, and Marathon runner John B. Johnson, who was diagnosed at 35.
The latest study was carried out in memory of two patients – Josh Wadlington and Spencer “Trigg” Robbins – who both fought against colon cancer despite marathons.
The research was presented at ASCO 2025 in Chicago, Illinois, the largest global gathering of cancer researchers.
Lee Rawlinson, who had previously ran marathons, learned that his grandfather had pancreatic cancer and he carries a “doubtful gene”. It is not clear if there is a link between long distance running and other early cancers
Holly Shawyer, 35, was diagnosed with pancreatic cancer last year despite his tip and training for a marathon. It is not clear if there is a link between long distance running and other early cancers
“I have always been fairly concerned about health – to look at what I eat and do regularly. I rarely fell ill, maybe once every few years, I would have a stomach bug, ” said Shawyer
Patients aged 35 to 50 who were ultramarathon runners were recruited for the study.
This was defined as people who had finished at least two 50 kilometers (31 miles) or more marathons, or five marathons of at least 42 km (26.2 miles) or more.
People who had an inflammatory intestine disease or other conditions related to colon cancer were excluded from the analysis.
Overall, the participants were an average age of 42 years, 55% were women and they said they traveled 32 to 64 km (20 to 40 miles) each week.
Between October 2022 and December 2024, patients underwent colonoscopy – screening for colon cancer where a flexible tube with a small camera at the end is placed in the colon.
Dr. Cannon said they were still investigating other factors that may have at risk of developing precancerous polyps.
Preliminary results had shown that runners ate at least five energy bars and also consumed gels daily – which are highly processed foods, foods in this category being previously linked to a higher risk of colon cancer.
Laurie Koshers (left) was diagnosed with colon cancer after “doing everything well”. She is vegetarian and also ran every day
Case cancer cases increase in under 50, even if they fall into older age groups
Dr. Cannon added: “I think I would have a colonoscopy if you have blood from your stool, even if you are not yet at the age when colonoscopies are approved – or at least I would ask your doctor.
“ I think that the bleeding of the rectum in runners is rejected because it is a known entity, the colitis of runners is known, and it is not known to be associated with cancer, so it is often rejected by doctors.
“But I hope that with, with more awareness, people who run long distance and who have bleeding will go colonoscopy.
“In our study, most people who had advanced adenomas had blood in their stools.”
The American Cancer Society Estimates of more than 154,000 Americans will be blocked by colorectal cancer this year, including around 20,000 under 50.
Although this is almost in accordance with two decades ago, the disease increases sharply in younger groups.
According to the latest data, the diagnostics of colon cancer early in the United States should Increase by 90% in people aged 20 to 34 between 2010 and 2030.
Among adolescents, rates have jumped 500% since the early 2000s.
