National Study Finds Higher Follow-Up Colonoscopy Rates After Positive mt-sDNA Than FIT

Key Takeaways

• In a national retrospective study, patients with a positive multitarget stool DNA (mt-sDNA) test were more likely to complete recommended follow-up colonoscopy within one year than patients with a positive fecal immunochemical test (FIT) or fecal occult blood test (FOBT).

• Follow-up colonoscopy completion after a positive mt-sDNA result was higher across all racial and ethnic groups evaluated, although disparities in adherence persisted.

• Patients with positive mt-sDNA results also underwent colonoscopy sooner than those with positive FIT/FOBT results.

• The study evaluated real-world adherence after positive stool-based screening tests and did not compare the clinical performance, cost-effectiveness, or overall effectiveness of the screening modalities.

Timely follow-up colonoscopy after a positive stool-based colorectal cancer (CRC) screening test is a critical component of the screening process, yet many patients do not complete the procedure. A new retrospective analysis published in the Journal of the National Comprehensive Cancer Network found that patients with positive multitarget stool DNA (mt-sDNA) test results were substantially more likely to undergo follow-up colonoscopy than those with positive fecal immunochemical test (FIT) or fecal occult blood test (FOBT) results.

The study linked national laboratory and claims databases to evaluate 362,646 average-risk adults aged 45 to 75 years who had a positive stool-based CRC screening test between 2016 and 2023. Investigators assessed completion of follow-up colonoscopy within one year, time to colonoscopy, and factors associated with adherence.

Overall, 77.1% of patients with a positive mt-sDNA result completed follow-up colonoscopy within 365 days, compared with 45.1% of patients with a positive FIT/FOBT result. After adjustment for age, sex, race and ethnicity, insurance type, geographic region, and comorbidity burden, mt-sDNA testing was the strongest predictor of follow-up colonoscopy completion, with an adjusted odds ratio of 3.98 compared with FIT/FOBT.

Higher adherence after positive mt-sDNA testing was observed across every racial and ethnic subgroup included in the analysis. Among Black patients, follow-up colonoscopy rates were 71.3% after mt-sDNA testing versus 44.6% after FIT/FOBT. Corresponding rates were 74.4% versus 45.1% among Hispanic patients, 74.2% versus 41.1% among Asian patients, and 77.2% versus 45.4% among White patients. Despite these differences, overall follow-up colonoscopy rates remained lowest among Asian and Black patients, indicating that disparities in the screening continuum persist.

The study also found shorter intervals between a positive screening test and diagnostic colonoscopy following mt-sDNA testing. More than half of patients with positive mt-sDNA results completed colonoscopy within 120 days across all racial and ethnic groups, whereas no FIT/FOBT subgroup reached 50% completion within one year. Among patients who underwent colonoscopy, the mean time to the procedure was 73.6 days after a positive mt-sDNA result compared with 90.9 days after a positive FIT/FOBT result.

The authors note that the study was designed to evaluate real-world follow-up adherence rather than compare the screening tests themselves. Although they suggest that features such as patient navigation incorporated into the mt-sDNA testing process may contribute to higher adherence, the analysis was not designed to determine the reasons for the observed differences. They also emphasize that decisions regarding stool-based screening strategies should consider factors beyond follow-up adherence, including test performance, patient preferences, healthcare system capacity, and cost-effectiveness.