Multitarget stool DNA test: clinical performance and impact on yield and quality of colonoscopy for colorectal cancer screening

• Published in: Gastrointestinal endoscopy 2017-03, Vol.85 (3), p.657-665.e1
• Main Authors: Johnson, David H., MD, Kisiel, John B., MD, Burger, Kelli N., BS, Mahoney, Douglas W., MS, Devens, Mary E., CCRP, Ahlquist, David A., MD, Sweetser, Seth, MD
• Format: Article
• Language: English
• Subjects: Adenoma - diagnosis; Adenoma - genetics; Aged; Carcinoma - diagnosis; Carcinoma - genetics; Colonic Polyps - diagnosis; Colonic Polyps - genetics; Colonoscopy; Colorectal Neoplasms - diagnosis; Colorectal Neoplasms - genetics; DNA - analysis; DNA, Neoplasm - analysis; Early Detection of Cancer; Feces - chemistry; Female; Gastroenterology and Hepatology; Humans; Male; Middle Aged
• ISSN: 0016-5107; 1097-6779
• DOI: 10.1016/j.gie.2016.11.012

Background and Aims Multitarget stool DNA (MT-sDNA) testing is now approved by the U.S. Food and Drug Administration for average-risk colorectal cancer screening. Trials leading to its approval used blinded colonoscopy as the reference standard. In the postapproval screen setting, the clinical performance and impact of MT-sDNA testing on unblinded colonoscopy has not been described. We measured the impact that knowledge of a positive MT-sDNA test result has on colonoscopy yield and quality. Methods The unblinded group comprised all patients with positive MT-sDNA results on screening from September 1, 2014 to September 30, 2015 at a single tertiary center. Off-label test patients were excluded. The blinded group included all MT-sDNA–positive participants in a preapproval screening study from the same center. Detailed colonoscopy findings and withdrawal times were recorded. Results There were 172 MT-sDNA–positive patients in the unblinded group and 72 in the blinded group. More total adenomatous/sessile serrated polyps (70% vs 53%, P  = .013) and advanced neoplasms (28% vs 21%, P  = .27) were detected in unblinded than in blinded groups. Median numbers of polyps detected were 2 (IQR, 1-4) and 1 (IQR, 0-2) in unblinded and blinded groups, respectively ( P  = .0007). Among polyps detected, flat or slightly raised lesions in the right side of the colon were proportionately more frequent with unblinded (40%) than with blinded examinations (9%) ( P  = .0017). Median withdrawal time was 19 minutes (IQR, 13-29) in the unblinded group compared with 13 minutes (IQR, 10-20) in the blinded group ( P  = .0001). Conclusions Knowledge of a positive MT-sDNA result appears to have a beneficial impact on the diagnostic yield and quality of subsequent colonoscopy.