Contemplating Colorectal Cancer Screening Choices

Kenny Lin, MD, MPH
Posted on June 10, 2024

Invitations to patients eligible for colorectal cancer screening need not be limited to office visits. A 2018 systematic review and meta-analysis of 73 randomized clinical trials of U.S.-based interventions found that mailing fecal tests more than doubled the likelihood that targeted patients received colorectal cancer screening. A recent trial in Clinical Gastroenterology and Hepatology compared screening completion in community health center patients randomly offered one of three options in an outreach mailing: colonoscopy referral only, fecal immunochemical test (FIT) only, or an active choice of colonoscopy or FIT. At 6 months, 12.8% of patients in the active choice arm had completed screening compared with 11.3% in the FIT-only arm and 5.6% in the colonoscopy-only arm.

As I discussed in a previous AFP Community Blog post, one problem with screening colonoscopy is that it is frequently repeated at shorter intervals than the recommended 10 years without a good reason. In fact, 10 years may not be long enough. A cohort study in JAMA Oncology suggested that a 15-year rescreening interval may be appropriate for average risk patients without a family history of colorectal cancer and with negative findings on their first screening colonoscopy. Using Swedish register-based data sources, researchers showed that individuals meeting these two criteria between 1990 and 2016 had 15-year standardized colorectal cancer incidence and mortality ratios that were lower than the 10-year cumulative risks in a matched control group.

A U.S. cross-sectional study that relied on data from the national Gastrointestinal Quality Improvement Consortium registry found that most patients with an episode of acute diverticulitis were not more likely to have colorectal cancer diagnosed on a follow-up colonoscopy than asymptomatic patients undergoing a screening colonoscopy. Only those with complicated diverticulitis (i.e., diverticulitis with perforation or abscess) were significantly more likely to have colorectal cancer (adjusted odds ratio = 3.57; 95% CI, 1.59 to 8.01).

Regarding the multitarget stool DNA (MT-sDNA) test for colorectal cancer screening, a study of 500 randomly selected patients in a Midwest health system found that about 1 in 5 had the test ordered inappropriately. The most common reasons for inappropriate ordering were having had a colonoscopy within the previous 10 years, having a family history of colorectal cancer, reporting symptoms suggestive of possible colorectal cancer, being younger than 45 years old, and having a previous diagnosis of adenomatous polyps.

A multitarget stool RNA (MT-sRNA) test with performance characteristics similar to those of the MT-sDNA test was approved in May 2024 by the U.S. Food and Drug Administration. Both tests are more sensitive for colorectal cancer and advanced adenomas than FIT but have lower specificity, resulting in higher false positive rates and more diagnostic colonoscopies. Of note, a research letter demonstrated that lowering the threshold for a positive FIT produced similar sensitivities and specificity as the MT-sRNA test, even without the RNA component of the test.