Multitarget Stool DNA Testing for Colorectal Cancer Screening in Clinical Practice

Few studies have evaluated multitarget stool DNA (mt-sDNA) in clinical practice. We analyzed mt-sDNA utilization at the University of Pittsburgh Medical Center.

We assessed mt-sDNA orders between January 1, 2017, and December 31, 2021. Data collection included electronic capture of mt-sDNA orders, completed stool submissions, and test results. Multivariable models were used to assess associations between mt-sDNA completion and results and age, sex, and race.

There were 91,664 mt-sDNA orders in 73,704 patients. A total of 54.7% (40,337/73,704) completed an mt-sDNA test, and 7,424 (18.6%) tested positive. Completion rates increased by age <50-59 years (N = 12,818; 48.2%), 60-69 years (14,982; 56.3%), and ≥70 years (N = 9,850; 55.6%) ( P < 0.0001). The completion rate for males (52.7%; 15,297/29,025) did not differ significantly from females (53.3%; 22,353/41,901) ( P = 0.09). By race, the completion rates of White patients (54.1%; 34,874/64,512) and Asian patients (56.9%; 493/867) were higher than those of Black patients (38.8%; 1,699/4,376) ( P < 0.0001). Test completion declined with repeat mt-sDNA orders, with ≤32% completion rate after ≥3 orders. In a multivariable model, older age was associated with greater likelihood of a positive test (odds ratio 1.22, 95% confidence interval 1.20-1.24, P < 0.0001), and Black patients had lower odds of a positive test (odds ratio 0.65, 95% confidence interval 0.56-0.76, P < 0.0001).

Only 54.7% of patients completed their mt-sDNA test order. Older individuals were more likely to complete testing and test positive. Black patients were less likely to complete testing and, unexpectedly, less likely to test positive. Further exploration of mt-sDNA utilization including better understanding of the determinants of uptake, appropriateness, and evaluation of outcomes at colonoscopy is needed.