Multitarget stool DNA (MT-sDNA) screening for colorectal cancer (CRC) had a high positive predictive value (PPV) when detecting colorectal neoplasia (CRN) in patients regardless of prior colonoscopy procedures. The results from this retrospective consecutive series cohort study were published in The American Journal of Gastroenterology.

MT-sDNA was assessed for its ability to predict CRN over a 39-month period. Patients included in the study were aged 50 years and older and were stratified into 2 groups: those with a previous colonoscopy (59%) and those without (41%).

Of the 16,469 MT-sDNA tests administered, 14.1% (n=2326) were positive. The investigators omitted data from patients with an increased risk for CRC in order to focus on those with CRN, resulting in 1801 patients for use in their analysis. The majority of patients with a positive MT-sDNA test (87%) underwent diagnostic colonoscopy.

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CRN was detected in 1558 patients, resulting in a PPV value of 67% (95% CI, 65%-69%). The rate of right-sided CRN was high among all study participants (79%; 95% CI, 77%-82%). The PPV for right-sided CRN was lower than for overall CRN, which had a value of 53% (95% CI, 51%-56%).

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The investigators reported more lesions in patients who did not have a prior colonoscopy (73%) than those with a previous endoscopy (63%; P <.0001). The cohort with no previous colonoscopy had a higher proportion of advanced CRN (49% vs 37%; P =.0002) but a lower proportion of right-sided CRN (77% vs 83%; P =.01).

A major limitation of this study is that study cohorts were not balanced. The cohort that did not have a previous colonoscopy were younger (median age 63 vs 70 years; P <.0001), used tobacco more frequently (53% vs 47%; P =.02), and were more often white (Caucasian 42% vs 39%; P =.008).

The study authors concluded that MT-sDNA had a high PPV for CRN in all patients regardless of prior exposure to endoscopy, indicating that this noninvasive procedure was effective at screening for CRN in some.

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Eckmann J D, Ebner D W, Bering J, et al. Multitarget stool DNA screening n clinical practice: high positive predictive value for colorectal neoplasia regardless of exposure to previous colonoscopy. Am J Gastrenterol 2020; 115(4):608-615. doi:10.14309/ajg.0000000000000546.