Screen for colon cancer recommended at age 45

But Cancer Society says colonoscopy isn’t required

“The best colorectal screening test is the one that gets done.”

Andrew Wolf Associate professor of medicine at the University of Virginia

Most people should start screening tests for colon and rectal cancers at age 45, rather than waiting for age 50, as long recommended, the American Cancer Society said Wednesday.

The group said the initial test does not have to be a colonoscopy, a procedure that typically requires a day off from work and an often-unpleasant bowel cleansing routine. Instead, it could be one of several other tests, including home stool tests available by prescription.

Other expert groups still recommend starting at age 50. That’s the stance of the influential U.S. Preventive Services Task Force, which last reviewed the issue in 2016.

But the shift by the cancer society is based on new information about the rise in colon and rectal cancer among younger adults, said Andrew Wolf, an associate professor of medicine at the University of Virginia. He led the group writing the new recommendations.

Colon and rectal cancers have increased 51% among adults under age 50 since 1994, the cancer society said.

“We don’t know why it’s going on,” Wolf said, noting that suspects include obesity and poor diet. “But it’s increasingly clear that it is happening.”

Meanwhile, cases and deaths have fallen in older adults, at least partly due to screening, which can lead to the detection and removal of polyps before they become cancerous.

Most of the nation’s 140,000 annual cases and 50,000 deaths from colon and rectal cancer still occur among people over age 55.

But the share of cases involving younger adults has risen to 29% for rectal cancer and 17% for colon cancer, a recent study showed.

While few trials have looked at screening 45-year-olds, new statistical models reviewed by the cancer society showed that the younger group should benefit nearly as much as slightly older adults do, Wolf said. But because the evidence is not as strong, the society said its recommendation for screening at 45 was “qualified.”

That means that “we hope that doctors will look at this and at least start discussions of colorectal cancer screening with their 45-year-old patients,” Wolf said.

It could be a complicated discussion. Not only do major groups now differ on starting ages, they also differ on how strongly they recommend various tests.

A group representing three professional societies of gastroenterologists said in 2017 that African Americans should start screening at 45, because they are at increased risk, but that others should wait until age 50.

It also said the best tests are colonoscopies every 10 years or a test called FIT (fecal immunochemical testing) to check for blood in the stool every year.

The group gave lower rankings to other screenings, including CT scans every five years or a stool test that checks for blood and DNA changes every three years.

By contrast, the cancer society said the tests are equally acceptable – though worrisome results on any test other than a colonoscopy need to be followed up with a colonoscopy.

“We do know that a lot of folks have distinct preferences when offered a choice,” Wolf said.

“The best colorectal screening test is the one that gets done.”