- Written by Elia Ben-Ari Elia Ben-Ari
Since the untimely death of 43-year-old Black Panther star Chadwick Boseman in 2020, the rapid rise in the rate of colorectal cancer among younger adults has been in the news. This increase played a key role in a revised recommendation by an independent U.S. advisory panel to start screening for colorectal cancer at age 45 instead of 50.
Screening for colorectal cancer, which can detect cancer and precancerous lesions before symptoms develop, has been shown to reduce deaths from the disease.
But while the U.S. Preventive Services Task Force updated its guidance to recommend screening for all adults aged 45-75, the panel concluded the “net benefit” of screening after age 75 is small and did not change its guidance for this age group.
However, a more recent study provides some evidence that screening for colorectal cancer appears to be beneficial for people beyond age 75 as well.
Although the study’s findings don’t contradict the advisory panel’s screening recommendations for older Americans — that is, that the decision should be made on a case-by-case basis — the researchers believe their results provide helpful information for physicians to use in discussing whether their older patients should get screened for colorectal cancer.
Because the task force suggests that decisions about screening people 76 to 85 years old be made selectively, “it’s been a bit of a gray area for physicians, and for [older] patients, to know what to do,” said Andrew Chan, M.D., M.P.H., a professor of medicine at Massachusetts General Hospital.
Chan co-led the study assessing the impact of colorectal cancer screening in more than 56,000 people aged 75 or older. His team found that the risk of dying from colorectal cancer was reduced by more than a third in people over age 75 who had been screened by colonoscopy or sigmoidoscopy.
Evidence Suggests Benefits of Screening beyond Age 75
Among more than 56,000 participants who reached age 75 during the study, the team identified 661 new cases of colorectal cancer and 323 deaths from the disease.
They then compared the rates of new colorectal cancer diagnoses and deaths from the disease among participants who reported having a screening colonoscopy or sigmoidoscopy after age 75 and those who did not undergo either test.
Screening after age 75 was linked with a 39% reduction in the incidence of colorectal cancer and a 40% decrease in the risk of death from the disease. The researchers found similar reductions in the risk of death from colorectal cancer, whether or not participants had ever undergone screening before age 75.
“Our data provide additional support for the USPSTF recommendations. And they give people more confidence that if they decide to continue screening beyond age 75, or even to start screening for the first time after age 75, there are data to support that decision,” Chan said.
More Research Questions to Address
The study’s results are far from the last word on this subject, researchers said. Because this was an observational study, “it is not completely clear if the improved outcomes are from the screening [test] or from the selection of patients to get screened,” Shivan Mehta, M.D., a gastroenterologist and health policy researcher at the University of Pennsylvania, said.
The researchers could not account for factors that may have influenced doctors’ decisions on whether to suggest screening to certain patients and people’s decisions to undergo screening, he explained.
For example, because colonoscopy is invasive and the preparation can be difficult, it’s possible that only the older participants who were fit and healthy underwent this screening test. And that could explain the lower death rate seen in the group that was screened.
“I hope we will reach a point where we can start to think about more sophisticated ways [than a person’s age] to help guide” decisions about colorectal cancer screening — for example, by looking at certain lifestyle factors or genetic risk factors that predispose some people to the disease, Chan said.
Although this study focused on colonoscopy, “there is increasing evidence of the value of noninvasive screening tests for colorectal cancer, such as stool-based testing,” which people can do at home and don’t require cleansing the colon, Chan said.
“And how those tests fit into screening recommendations for people over age 75 remains an area for future research.”
“Should People Over Age 75 Be Screened for Colorectal Cancer?” was originally published by the National Cancer Institute.