Colorectal Cancer on Rise in Young Adults, Answers May Be Years Away

Colorectal cancer is on the rise among younger adults, although potential explanations for the cause of this trend are likely years away, according to experts.

Although overall rates of colon or rectal cancer have dropped since the mid-1980’s, and fell by approximately 1% per year from 2012 to 2021, that downward trend was mostly among younger adults, the American Cancer Society reported, noting that among people younger than 50, rates climbed by 2.4% per year from 2012 to 2021.

“It'll probably take years, many years, to figure this out, because while the risk is increased, it is actually still exceedingly rare that young individuals have colorectal cancer. And therefore, in order to get enough people with colorectal cancer to do any sort of significant research on it, it takes many, many years to track this, and so we right now have our theories, but it will be a long time before we're able to pick one over the other,” said Dr. Zachariah H. Foda.

Foda is an assistant professor of medicine at Johns Hopkins School of Medicine in Baltimore and leads the Johns Hopkins Colon Cancer Risk Assessment Clinic.

Transcript:

There are many theories on why this is happening, and some of these theories have been explored and are currently being explored in extensive research. Researchers throughout the country and the world are examining what is sometimes called early-age onset colorectal cancer, or also variably termed the birth cohort effect. This means that it's not necessarily just young-onset cancer that's increasing in people born in later decades; rather, all colorectal cancer incidence is increasing across later decades.

Because this is something that is affecting a large number of people, or an entire cohort, the most likely explanation has to do with something in the environment, whether that's new foods, new chemicals, or universal changes in lifestyle. We haven't been able to narrow it down yet. It will probably take years, many years, to figure this out, because while the risk is increased, it is still exceedingly rare for young individuals to have colorectal cancer. Therefore, in order to gather enough people with colorectal cancer to conduct any sort of significant research on it, it takes many, many years to track this. So, we currently have our theories, but it will be a long time before we're able to definitively choose one over the others.

Transcript has been edited for clarity and conciseness.

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