Debate: Colorectal Screening at 45, Yea or Nay?

SAN DIEGO — Two physicians who have led national gastroenterology organizations squared off here over the wisdom of beginning routine colorectal screening at age 45. One said it’s time to expand the start-at-45 recommendation beyond African Americans now that racial disparities in colon cancer have dwindled. The other declared that “screening everyone at 45 goes against the principles of precision medicine.”

At issue in the debate, conducted at the annual Digestive Disease Week meeting: Should people at average risk start undergoing colorectal screening at age 45 instead of 50? Last year, the American Cancer Society said they should, and it recommended regular screening via high-sensitivity stool-based tests or visual exams such as colonoscopy.

Other groups did not rush to embrace the high-profile recommendation. The U.S. Multi-Society Task Force on Colorectal Cancer, which represents the American Gastroenterological Association (AGA), the American College of Gastroenterology (ACG), and the American Society for Gastrointestinal Endoscopy, pointedly declined to endorse it.

At the debate here, Douglas Rex, MD, a former ACG president affiliated with Indiana University School of Medicine, pointed out that the task force does recommend that African Americans begin screening at age 45 because of their heightened risk. It continues to make this recommendation, he said, even amid a declining racial gap in colorectal cancer rates at ages 20-49.

Rex pointed to a 2019 study that tracked colorectal cancer rates from 1992-1996 to 2010-2014. They grew markedly among whites from 7.5 to 11.0 per 100,000 while edging up slightly in blacks (11.7 to 12.7 per 100,000).

“There’s less racial disparity,” he said, “and it’s reasonable to consider whether the recommendation should apply to all racial groups.”

He added that about half of all colorectal cancer in people under age 50 occurs in the 45-49 age group. “We assume that screening works in high-risk groups under 50,” he said. “It’s a stretch to believe it will work in 50-54 year olds and not 45-49 year olds.”

But, will more colorectal screening overwhelm the American health system? Rex didn’t think so. “There are 22 million Americans age 45-49. Of course, they won’t all show up at once. And there is no evidence that colonoscopy resources in the U.S. are exhausted.”

He added: “We are a wealthy country. Why don’t we do it all? We can certainly increase adherence rates over the age of 50 and also screen those that are 45-49 years old. It’s cost-effective to do it by the models we have available.”

On the other side, David Lieberman, a gastroenterologist at Oregon Health & Science University and current president of the AGA, argued against universal screening at age 45.

It’s true that the burden of colorectal cancer under the age of 50 is growing, he said, and there appears to be more to the increase than simply a rise in colonoscopies.

“Some studies speculate about obesity, sedentary lifestyle, and ultra-processed foods,” he said. “The bottom line is we’re not sure why we’re seeing this trend. A logical approach would be to understand who is at high risk and target early screening for them.”

In terms of risk, patients with family histories of colorectal cancer are the “lowest hanging fruit,” said Lieberman, who emphasized the importance of regularly asking patients about the health of their relatives. Screening is also important in patients who show symptoms, especially rectal bleeding that appears to be related to hemorrhoids but may be a sign of something more serious, he said.

Moving forward, he said, more research is needed to understand the worldwide increase in colorectal cancer cases and pinpoint groups at higher — or lower — risk. Smokers and people with high body mass indexes may be at higher risk, he said, while non-black, pre-menopausal women appear to be at lower risk.

Lieberman added that it’s important to understand ways to reduce risk other than screening, such as lifestyle changes. Also, he asked, “what’s the best form of screening? Maybe it’s sigmoidoscopy or a FIT [fecal immunochemical test]. It might not necessarily be colonoscopy at age 45.”