Why Is Colorectal (Colon and Rectal) Cancer Targeting Young People?

Although considered a disease of older people, colorectal cancer is now targeting people younger than 50, sometimes decades before the recommended first screening age.

Colonoscopy (large bowel imaging with a flexible camera-tipped tube), stool tests and frequent screening and surveillance have reduced colorectal incidence and mortality in those aged 50 and over. Yet incidence under 50 is rising rapidly in developed countries for unclear reasons.

Statistics from 1992-2005 in America showed annual colorectal cancer incidence increases per 100.000 young people of 1.5% in men and 1.6% in women. Earlier, between 1973-1999, young people’s colon (17%) and rectal (75%) cancer incidence rose.

Higher mortality among young patients appears related to advanced diagnosis. One study found those aged 50 and younger had symptomatic disease at diagnosis in 86%, meaning it already caused signs and complaints.

Advanced diagnosis is concerning. Young people may not recognize symptoms, and doctors may consider cancer unlikely, delaying treatment. Initial diagnosis is wrong in approximately 15%-50% of young-onset cases. Supporting research into distinctive characteristics and raising patient and physician awareness matter.

Doctors previously thought inherited conditions, particularly Lynch Syndrome , were responsible for colorectal cancer in young adults. Today, however, more than 75% of young patients are known not to have familial disease or hereditary cancer. Moreover, Lynch Syndrome is associated with tumors developing on the right side of the colon, while nonhereditary cancers in young adults consist of tumors in the left colon and rectum. This indicates that nonhereditary colorectal cancer in young people is biologically quite different.

Experts investigating young-onset biology note colon cancer differs between individuals, with unique genetic signatures even in the same organ.

To examine this complexity, genetic profiles from approximately 5000 patients were investigated, defining differences in young and older tumors separately. Results are awaited.

Beyond these factors, experts investigate others affecting the increase. Epidemiological trends in adults under 50 show that over the last 30 years, increasing obesity and diabetes have paralleled rising colorectal rates in the same ages. Whether causal or not, the parallel increase cannot be ignored.

More sugary drinks and fewer dairy products (protective calcium) may also increase incidence. Healthy, careful diets in young adults will therefore reduce not only diabetes but colorectal cancer risk.