Colorectal cancer incidence rising among young adults

UCI Health-led study also shows increased risk in some ethnicities

January 28, 2015

The incidence of colorectal cancer is increasing in young adults while the rate among those older than 50 years of age continues to decline, according to a UC Irvine-led study published in the Journal of Adolescent and Young Adult Oncology.

Researchers analyzed more than 231,500 colorectal cancer cases reported in the California Cancer Registry over a 22-year period and found significant increases in colorectal cancer incidence among the 20-29 and 30-39 year-old age groups. Colorectal cancer is not common in people under 50 years old, the age at which screening with colonoscopies or other colorectal screening tests commence for average-risk individuals. In addition, the data showed greater risk among different age cohorts and in certain racial or ethnic groups among young adults.

“While the overall risk of colorectal cancer among young adults in the U.S. remains low, the risk is increasing, which is in direct contrast to what is seen in the ‘screened population,’ those age 50 and over,” said UCI Health oncologist Jason Zell, DO, assistant professor of medicine. “Physicians and patients need to be aware of this trend, and recognize the changing epidemiology of the disease.”

Zell said the findings of increased cancer incidence among some ethnicities and that the stage of cancer once diagnosed was higher in the young adult group needed more study to determine how patients with young-onset colorectal cancer differ from young people without the disease. Identifying high-risk groups could lead to improved methods for colorectal cancer prevention. 

“Among Hispanic females in the 20-29 age group we observed a nearly 16 percent bi-annual increase in colorectal cancer risk over the 22-year study period,” Zell said.  “The study also found that young adults were more likely to be diagnosed at an advanced stage compared with adults in the “screened population,” those age 50 and over.”

Colorectal cancer is the third most common cancer diagnosis and the second-leading cause of cancer death in the U.S. Screening to detect and remove precancerous polyps among adults older than age 50 has largely contributed to declining colorectal cancer rates for the U.S. population as a whole.

Researchers contributing to the journal article "Colorectal Cancer Incidence Among Young Adults in California" included Kathryn Singh, MPH, MS; Thomas Taylor, PhD; Chuan-Ju Pan, MD; Michael Stamos, MD; and Zell.

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