The American College of Physicians issued updated guidance for colorectal cancer screening of average-risk, asymptomatic adults on Monday, urging against the use of computed tomography colonography, or CTC. Its decision drew criticism from the radiology community, which has fought to increase awareness around this alternative to colonoscopy.

ACP said its decision was based on a critical review of existing clinical guidelines and evidence, which unearthed no eligible studies evaluating the effectiveness of CTC. The largest medical specialty organization in the U.S.—with over 160,000 members in internal medicine and related subspecialties—also advocated against stool DNA, capsule endoscopy, urine or serum screening tests.

“Computed tomography colonography also leads to a high frequency of extracolonic findings of uncertain benefit or harm,” Omar T. Atiq, MD, president of the American College of Physicians, told Radiology Business by email. “A positive CTC requires follow-up colonoscopy, which reduces its utility as a direct visualization test,” he added.

The American College of Radiology on Monday labeled the guidance as a “step backward—particularly in underserved communities where screening rates are lower and CRC death rates are much higher.” ACP’s announcement also recommends beginning routine screening at 50 years old rather than 45, contradicting advice from the American Cancer Society, which also has endorsed CT.

“About a third of those who should be screened for [colorectal cancer] can’t or won’t get a colonoscopy. We need more testing options—not fewer,” the American College of Radiology said in a July 31 statement.   

ACR also noted that the U.S. Preventive Services Task Force has endorsed CT as screening alternative to colonoscopy. Several studies have demonstrated that a “virtual colonoscopy” “significantly boosts” screening rates while lowering costs, the American College of Radiology added.

“Recent census data shows that more Black and Hispanic people are getting screened with CTC compared to whites. Denying access to a test that is increasing screening in at-risk communities is not helpful,” the ACR added. “CT colonography is an accurate, safe and minimally invasive test that does not require sedation, allows people to go back to their daily activities, and is a preferred option for many who otherwise may not be screened.”

Colorectal cancer has the fourth highest incidence rate and is the second leading cancer killer in the U.S., the ACP noted. Its new guidance is aimed at helping physicians determine when to start and stop screening, along with selecting the proper testing option. The American College of Physicians is advocating against screening asymptomatic, average-risk adults between 45 and 49, along with halting testing for those over 75.

Options and intervals endorsed by the ACP include a fecal immunochemical or high-sensitivity guaiac fecal occult blood test every two years, colonoscopy every 10 years, or flexible sigmoidoscopy every 10 years.

“This updated guidance will help physicians determine the evidence-based course for their patients for screening for colorectal cancer and to avoid unnecessary screening in this population,” Atiq said in a statement issued Monday. “Physicians and patients should select the screening test based on a discussion of the benefits, harms, costs, availability, frequency and patient preferences.”

You can read the updated guidelines in the Annals of Internal Medicine, along with a corresponding editorial.