New guideline for colorectal cancer exams cuts age to 45

For decades doctors have recommended colorectal cancer screenings for people 50 and older but now the American Cancer Society says screenings should begin at age 45 for people of average risk.

A recent analysis found that adults born around 1990 have twice the risk of colon cancer and four times the risk of rectal cancer compared with adults born around 1950, the cancer society said.

“When we began this guideline update, we were initially focused on whether screening should begin earlier in racial subgroups with higher colorectal cancer incidence, which some organizations already recommend,” Richard C. Wender, the Cancer Society’s chief cancercontrol officer, said in a statement.

“But as we saw data pointing to a persistent trend of increasing

colorectal-cancer incidence in younger adults, including American Cancer Society research that indicated this effect would carry forward with increasing age, we decided to re-evaluate the age to initiate screening in all U.S. adults.”

The Cancer Society also says the colorectal cancer risk in the 45-49 age group actually is similar to the 50-54 group, given increased diagnoses in the older group with its much higher screening rate.

Not all physicians are embracing the new guideline, including Robert E. Schoen, UPMC chief of the division of gastroenterology, hepatology and nutrition.

“Why do I disagree? What we’re doing now is working. We have seen very dramatic declines in incidence and mortality. Not only are we finding early cancers but we are preventing them from actually coming to the fore. This is true prevention.”

Considered optimal is the colonoscopy, an endoscopic procedure involving a camera and flexible tube that is used to find and remove precancerous polyps and identify other bowel conditions.

But with the “qualified” recommendation — more of a serious suggestion than strong recommendation — the Cancer Society says people 45 to 49 can undergo either “a high-sensitivity stool-based test or a structural visual exam, depending on patient preference and availability.”

Such screening tests include the colonoscopy, the fecal immunochemical test, the high sensitivity guaiac-based fecal occult blood test, the multi-target stool DNA test, CT colonography or the flexible sigmoidoscopy, each with its own recommended intervals for retesting.

Those with positive results for a non-colonoscopy test typically are advised to undergo a colonoscopy, with current recommendations to undergo a colonoscopy every 10 years until age 75, with clinicians advising on colonoscopies up to 85, the age when they no longer are recommended. More frequent colonoscopies are advised for patients with family histories of colorectal cancer or those who’ve had polyps removed.

Colorectal cancer incidence actually has steadily declined in recent decades in people 55 and older due to screenings and polyp removal, along with dietary improvements and exercise, the Cancer Society said in its announcement.

Still, it says, there has been a 51 percent increase in colorectal cancer among those younger than 50 since 1994.

The recommended shift to age 45 is based on a benefit-burden ratio — a computer model that judges success rates versus risks of undergoing a colonoscopy that can include such complications as rupturing of the bowel with a small risk of death.

Colonoscopy screening beginning at 45 rather than 50 “provides a slightly more favorable balance between the benefits and burden of screening,” the Cancer Society says.

The Allegheny Health Network did not respond to a late request for comment. But Dr. Schoen of UPMC listed many concerns about adopting the new recommendation.

• “The increasing incidence of colorectal cancer in younger people is important and requires more study,” he said. “The reasons for it are not understood and certainly merit more investigation.”

• The recommendation is based on modeling, “not reality,” based on “estimations, assumptions and uncertainties. “We must be careful not to ascribe the same evidence to modeling as we do with actual clinical trials.”

• The 45-49 age group has half the risk of someone 50-54 and one-third that of 60 to 64 year olds. “We must realize this is a lower risk group, and we haven’t come close to the participation in screening we want in the higher risk groups today in the United States. For age 50 and above, 47 percent are not up to date with current recommendations.

“We should be devoting resources to getting those people screened before adding lower risk groups for testing,” he said.

• A final factor is whether there is medical capacity to begin testing that age group 45-49, which contains 22 million Americans. “It would be a shame to screen a lot of low-risk subjects in lieu of testing those at greater need with greater likelihood to benefit,” he said.

“I favor broader consideration of the implications before running ahead with changing the guideline,” he said.