P0566 - Adenoma Detection Rate After Positive Stool-Based Screening and Risk of Interval Post-Colonoscopy Colorectal Cancer

Award: Presidential Poster Award

Thilini Delungahawatta, MBBS¹, Richard Hum, MS², Stephanie M. Woo, MD³, Thomas Loughney, MD³, Joseph Jennings, MD^3
1MedStar Health, Baltimore, MD; ²Georgetown University School of Medicine, Washington, DC; ³MedStar Georgetown University Hospital, Washington, DC

Introduction: Increasing adenoma detection rate (ADR), defined as the proportion of screening colonoscopies that detect at least one adenoma, is inversely correlated to incidence of interval colorectal cancer (CRC). The current recommended benchmark for primary screening colonoscopy ADR is 20% in female patients and 30% in male patients. However, there is limited evidence for ADR targets after positive stool testing and its relationship with interval colon cancers. Recent data from a Dutch CRC screening program suggested that median ADR after positive fecal immunochemical test (FIT) was 67% and inversely related to interval CRC.

Methods: All stool-based screening participants (fecal occult blood test (FOBT), FIT, FIT-DNA test) receiving a positive test result who underwent a first colonoscopy between January 1^st, 2017 and December 31^st, 2021 at our institution were included. Retrospective chart review was performed to determine the ADR (number of procedures completed with detection of at least 1 adenoma divided by total number of procedures done during time period) and interval colon cancers (any CRC diagnosed ≥ 6 months after first colonoscopy in which no CRC had been diagnosed).

Results: From a total of 120 patients identified (32 FOBT, 43 FIT and 45 FIT-DNA participants), the average ADR was 65.8%. Serrated polyps were the most identified lesion (55%). No interval cancers were identified within our sample. Assessment of other quality indicators revealed Boston Bowel Preparation Scale ≥6 points in 92.8% of procedures and colonoscopy withdrawal time ≥6 minutes in 95.4% of procedures.

Discussion: Endoscopists within our institution had similar ADRs and quality indicators to endoscopists in the Dutch screening program and therefore, we may infer comparable correlation to interval colon cancer risk. Data also suggest a trend towards increasing ADR from FOBT to FIT to FIT-DNA screening. Nevertheless, the number of colonoscopies and interval colon cancers in this study was not sufficient to detect an inverse association. Our study period may have limited data collection on interval colon cancers in patients with longer surveillance recommendations. Further data collection with an extended study time period and across affiliated institutions may be better able to showcase suitable ADR targets after positive stool-based screening tests. As an indirect measure of endoscopic technical quality, we urge endoscopists to continue to improve ADR to better patient health outcomes in gastroenterology.




Disclosures:


Thilini Delungahawatta, MBBS¹, Richard Hum, MS², Stephanie M. Woo, MD³, Thomas Loughney, MD³, Joseph Jennings, MD³. P0566 - Adenoma Detection Rate After Positive Stool-Based Screening and Risk of Interval Post-Colonoscopy Colorectal Cancer, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.