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Experts advise: Start colorectal screening at 45, not 50

The guidelines are a response to a decades-long rise in diagnoses among younger Americans

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10:50am, May 31, 2018
colonoscopy

SCREEN TIME  A colonoscopy, which involves inserting a long, flexible tube with a video camera at the tip into the rectum, is one of six tests the American Cancer Society suggests to screen for colorectal cancer. The group now recommends screening begin at age 45.

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Colorectal cancer screening should begin at age 45 rather than 50, according to new guidelines released May 30 by the American Cancer Society. The recommendation is a response to the steady rise over decades in the colorectal cancer rate in younger Americans (SN: 4/1/17, p. 5).

For people at average risk for colorectal cancer — those without a personal or family history of the disease and who haven’t had inflammatory bowel disease — the ACS suggests regular screening begin at 45 with either stool-based tests or visual exams, such as a colonoscopy. The new ACS guidelines, published in CA: A Cancer Journal for Clinicians, equally endorse six possible screening methods.

Different directions

The rates of new colorectal cancer cases have declined among men and women age 50 and older in recent decades. But the rates of diagnoses among people ages 20 to 49 have been increasing.

graph of trends in colorectal cancer rates

Colorectal cancer is the second-most common cause of cancer death in the United States. Lifestyle choices such as smoking cigarettes, drinking alcohol, not exercising, eating processed and red meats and forgoing fruits and vegetables can increase a person’s risk for the disease.

The ACS says that screening can catch precancerous polyps and early-stage cancers, when they may be more easily treated. Journalist Katie Couric, whose husband died of colorectal cancer, and comedian Jimmy Kimmel have televised their colonoscopies to encourage viewers to get screened.

“Overall rates of colorectal cancer have declined by more than 45 percent since the 1980s, owing in part to screening,” says gastroenterologist Andrew Chan at Massachusetts General Hospital in Boston who was not involved in the guidelines. “In sharp contrast, the rates of colorectal cancer have been increasing among all age groups between 20 and 49.” Those ages have experienced a 51 percent rise in the incidence of colorectal cancer since 1994.

Scientists aren’t sure why the disease is increasing among younger Americans. But Chan says it’s not just in relation to the older group; the absolute case numbers are going up in the younger group, too. “The increase we are seeing is not simply a reflection of the drop in cancer among older groups who are being screened.”

Citations

A.M.D. Wolf et al. Colorectal cancer screening for average-risk adults: 2018 guideline update from the American Cancer Society. CA: A Cancer Journal for Clinicians. Published online May 30, 2018. doi:10.3322/caac.21457.

Further Reading

T.H. Saey. Colorectal cancer is on the rise among younger adults. Science News. Vol. 191, April 1, 2017, p. 5.

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