Colorectal cancer is on the rise among younger adults

Unhealthy lifestyle linked to increase in tumor incidence, death rates

X-ray of colon tumor

ON THE RISE  For decades, colorectal cancer rates have been falling, but a new report finds an uptick in the rates among U.S. adults under 50. Here, an X-ray illustrates where a colon tumor (green) has constricted the large intestine.

Biophoto Associates/Science Source

In recent years, rates of colorectal cancer cases and deaths in the United States rose among young and middle-aged adults, an American Cancer Society study of colorectal cancer trends between 2000 and 2014 finds. That increase came even as rates of colon and rectal tumors and deaths dropped in people 50 and older, researchers report online March 1 in CA: A Cancer Journal for Clinicians.

Few people who are under 50 get colorectal cancer, but the incidence in this group has risen since 2000, from 5.9 new cases diagnosed in every 100,000 people to 7.2 per 100,000 in 2013. In contrast, the incidence rate for people age 50 and older was 119.3 per 100,000 in 2013. New cases are still most prevalent in people 65 and older: 58 percent of the estimated 135,430 new diagnoses projected for 2017 will occur in that age group.

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Overall, colorectal cancer incidence and death rates are declining. This drop is attributed to decreases in smoking and red meat consumption, an increase in aspirin usage — which can calm inflammation that spurs tumor growth — and improvements in screening and treatment. Increased prevalence of obesity, unhealthy diets and sedentary lifestyles contributed to the rise in colorectal cancer cases and deaths among adults younger than 50, the researchers suspect.

Editor’s note: This article was updated on March 2, 2017, to include absolute incidence rates. 

Tina Hesman Saey is the senior staff writer and reports on molecular biology. She has a Ph.D. in molecular genetics from Washington University in St. Louis and a master’s degree in science journalism from Boston University.

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