Testing Trends: The Debate Continues Over Regular Colorectal Screening for Average Risk Adults

Should adults age 50 to 75 who are at average risk and show no symptoms of colorectal cancer have regular colorectal screening exams? Last month, a major medical journal came out against regular screening. But just a few weeks later, the powerful and influential American College of Physicians (ACP) issued New Guidance in favor of regular screening, the same position taken by the American Cancer Society (ACS) a year earlier. Here is a rundown of the ACP’s recommendations.

To Screen or Not To Screen

Colorectal cancer is the second leading cause of cancer-related death in U.S. adults. After declining overall from 1970 to 2004, colorectal cancer death rates among 20- to 54-year-old adults climbed by 1% annually from 2004 to 2014, according to a 2017 study published in the medical journal JAMA.

In May 2018, the ACS issued guidance recommending that average-risk adults start regular screening at age 45, diverging from the previous consensus recommendations that screening begin at age 50. Adding to the debate, in early October 2019, The BMJ issued guidelines recommending against colorectal cancer screening in healthy people aged 50 to 79 who are at low risk for the disease, citing a lack of evidence that the practice benefits this population. The journal did, however, recommend screening for people in this age group who have a 3 percent or greater colorectal cancer risk. For more on The BMJ recommendations, see Diagnostic Trends and Emerging Technology (DTET), Oct. 16, 2019.

The question of how colorectal screening should be performed has also been subject to debate. Recommended screening methods include fecal-based tests, colonoscopy and sigmoidoscopy.

While the consensus view is that colonoscopy should be used as the primary screening tool, the Canadian Task Force on Preventive Health Care recommends not using colonoscopy as a primary screening test.

The ACP Weighs In

After analyzing the conflicting recommendations, the ACP issued guidelines published in the Annals of Internal Medicine in early November 2019 recommending regular colorectal cancer screening for asymptomatic adults age 50 to 75 who are at average risk for the disease. ACP defines “average-risk individuals” as those without a personal or family history of colorectal cancer, a long-standing history of inflammatory bowel disease or genetic syndromes such as familial adenomatous polyposis. Adults with a higher risk or family history of the disease should speak to their doctor and get screened more regularly, the ACP adds.

Relying on direct evidence from research studies over modeling data, the ACP’s clinical guidelines committee (CGC) declined to recommend any one screening approach over the others since none of the reviewed guidelines directly compared screening interventions. “All screening tests are associated with potential benefits as well as harms,” according to the CGC. It recommends that doctors and patients make individual decisions on selection of test methods based on benefits, harms, costs, availability, frequency and patient preferences.

However, the ACP did make recommendations on screening intervals depending on method, including:

• Fecal immunochemical test (FIT) or high sensitivity guaiac-based fecal occult blood test (gFOBT): every two years;
• Colonoscopy: every 10 years
• Flexible sigmoidoscopy: every 10 years with an FIT every two years.

Takeaway

Regular colorectal cancer screening for average, asymptomatic adults between age 50 and 75 remains a hotly debated topic. In the past 18 months, no fewer than three heavyweights have weighed in on the issue and offered conflicting recommendations.

The Scorecard:

•  American Cancer Society (May 2018): Yes
• The BMJ (October 2019): No
• American College of Physicians (November 2019): Yes