Colon Cancer in Young People: Not an Obesity Issue

John L. Marshall, MD


April 14, 2023

Editorial Collaboration

Medscape &

This transcript has been edited for clarity.

It's John Marshall for Medscape. It has been a little bit of time, but I'm still here. I have less hair and the same junk all over my office, but it is good to be back.

I wanted to talk today about a really important subject: young people with colon cancer. The Washington Post decided to run an article on it recently, right below the "Trump Can Be Sued" article. It's quoting some people from the American Cancer Society and all others who should be authorities on what the problem is all about.

But I don't think they're right.

Let me tell you the problem. When I first started 30 years ago, there was nobody in my clinic who was under the age of 50 with colon cancer. There was an occasional patient with Lynch syndrome, but nobody else was under the age of 50. Today, in 2023, more than half of my clinic is under the age of 50, and many are in their 20s and 30s.

This article talks about obesity. None of these patients are obese. In fact, they're all marathon-running, cardboard-eating people. They're fit, they're healthy, and they have no family history. We don't know why they got it. In fact, we are looking at patients who are even hyper-exercisers and understand that maybe they are getting more dysplasia than other patients.

Second, pretty much all of them have left-sided colon cancer, rectosigmoidal cancers. The cancers are all clustered right there. They're not distributed around the bowel, as we normally would see. They're all in the same location.

Third, many of these people have been screened already. Yes, we shifted it to 45, so more and more patients are getting screened then, but it really makes me question our screening technologies and techniques. We are looking for a cancer that has a long arc to it, where a polyp takes 5-15 years to become cancer.

Yet, many of these people that we're seeing had some screening or they had no evidence of anything going on, and suddenly they have stage II, stage III, and stage IV colon cancers. I saw a 55-year-old just last week who had dutifully gotten his colonoscopy at age 50, and in fact, now had stage IV disease. Clearly, our screening techniques are not everything we think they are and should be.

I think we need to come to some reckoning. The whole point of this is that we don't know what we're doing. We don't know how to best screen people. We don't understand why these young people are getting colon cancer.

I think to blame it on old theories around obesity and other things like that is wrong and is not doing anybody a good service. I believe that it's going to be found in understanding better the microbiome, and there is now more research.

One of the positives of these young people getting colon cancer is that more and more research money is being filtered into the science of understanding the microbiome and other pieces of our health. I'm hopeful that we will uncover critical, new findings here.

To highlight in The Washington Post that this issue is related to obesity — to teach everybody a lesson not to be fat — is dumb, is not appropriate, and doesn't help our overall messaging and understanding of this complicated disease.

I hope somebody out there is listening. We need more money for research into understanding why these marathon-running, cardboard-eating young people are getting these left-sided colon cancers.

I don't want them in my clinic. I'm tired of taking care of these young people with serious illnesses. Let's figure this out.

I'm John Marshall for Medscape.

John L. Marshall, MD, is a leader in the research and development of drugs for colon cancer and other gastrointestinal cancers, and he has been the principal investigator of more than 150 clinical trials. Marshall is the founding director of the Otto J. Ruesch Center for the Cure of Gastrointestinal Cancer, chief of the Division of Hematology-Oncology at Georgetown University, and the clinical director of oncology for Georgetown University Hospital.

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