S520 Updated Quality Indicators for Colonoscopy in Patients With Positive Fecal Screening Tests

Introduction: In August 2024, The American Journal of Gastroenterology released updated multisociety guidelines on colonoscopy quality indicators, including a 50% adenoma detection rate (ADR) benchmark for FIT and mt-sDNA positive patients and a longer withdrawal time (≥8 minutes). This study evaluates baseline ADR at our institution and the findings that may contribute to false positive screening tests. Methods: We performed a retrospective review from August 2022 to August 2024 across 2 campuses, including patients aged ≥45 who had colonoscopy after positive FIT or mt-sDNA. Data included demographics, polyp characteristics, and hemorrhoid grading. Results: Among 378 patients (284 mt-sDNA, 94 FIT), demographics were similar; mean age was ∼63 years. Most were non-Hispanic (Cologuard: 90.5%, FIT: 80.9%). ADR met or exceeded the 50% benchmark for both groups, with significantly higher rates in FIT (81.9%) vs mt-sDNA (66.6%) (P = 0.0036). Tubular adenomas were the most common lesions in both cohorts. Large TAs (>1 cm) were more frequent in mt-sDNA (22.2% vs 20.2%), but not statistically significant (P = 0.6781). SSAs were more prevalent with mt-sDNA (23.9% vs 14.9%), trending toward significance (P = 0.0741). FIT had significantly more large TVAs (10.6% vs 3.9%; P = 0.0069). HPs <1 cm were more common in mt-sDNA (32.7% vs 25.5%) though not statistically significant (P = 0.2162). Cancer rates were similar (mt-sDNA: 3.5%; FIT: 5.3%; P = 0.487). False positives were more frequent with mt-sDNA (21.8% vs 18.1%), though not significant (P = 0.4524). Hemorrhoids were the most common alternate finding (grade ≥2: 30.7%; < grade 2: 38.7%). Conclusion: These findings support the new ADR benchmark for stool based colorectal cancer screening tests. While mt-sDNA detects a broader lesion range, FIT shows superior ADR and TVA detection. mt-sDNA’s broader sensitivity may reduce specificity due to benign findings like hemorrhoids and hyperplastic polyps.