P1307 - Sessile Serrated Polyp Detection Rate of 2% or Greater Is Associated With a Lower Risk for Post-Colonoscopy Colorectal Cancer

Award: Presidential Poster Award

Award: Presidential Poster Award

Joseph Anderson, MD¹, William Hisey, MS², Todd Mackenzie, PhD³, Christina Robinson, MS⁴, Lynn Butterly, MD^2
1White River Junction VA Medical Center, Hanover, NH; ²Dartmouth-Hitchcock Medical Center, Hanover, NH; ³Dartmouth College Geisel School of Medicine, Hanover, NH; ⁴Dartmouth-Hitchcock Medical Center, Lebanon, NH

Introduction: Adequate serrated polyp detection rates, especially for sessile serrated polyps (SSPDR) may reduce the risk of post colonoscopy CRC (PCCRC) but there are no data examining SSPDR. We used New Hampshire Colonoscopy Registry (NHCR) data to compare the PCCRC risk in exams performed by endoscopists with an SSPDR of 2% (Desai et al (Endosc Int Open 2021)) or greater to those with a lower SSPDR. We also examined clinically significant serrated polyp (any sessile serrated polyp (SSP), traditional serrated adenoma (TSA), large ( >1cm) hyperplastic polyp (HP), or proximal HP 5-9 mm) detection rate (CSSDR) of 7% (Anderson/Butterly (GIE 2017)) as well as adenoma detection rate of 25%.

Methods: We included NHCR patients with 1 or more follow up event, either a colonoscopy or a CRC diagnosis from the NH State Cancer Registry which collects data from NH, VT, MA, ME. Our outcome was PCCRC diagnosed 6-36 months after an index exam and those diagnosed 6-60 months after an index exam. Since some patients with CRCs had multiple exams and were diagnosed after 1st surveillance exam, we did a sensitivity analysis by restricting data to 1st follow up. Exclusions were any CRC diagnosed at index or within 6 months, incomplete exams, IBD, and genetic syndromes. The exposure variables were endoscopist specific SSPDR rates of 2% (screening exams with 1 SSP/ all screening exams) as well as a CSSDR of 7% and an ADR of 25. Cox regression was used to model the hazard of PCCRC on the detection rates controlling for age, sex, index findings, bowel prep, having more than 1 surveillance exam and family history of CRC.

Results: From our database of 142,950 index exams (138 endoscopists), we analyzed 9023 exams and 82 CRCs during the 6-60 months. The absolute risk for PCCRC was lower for exams performed by an endoscopist with an SSPDR of 2% or greater (0.6% (32/5380) vs 1.4% (50/3643); p < 0.0001). The results were similar for ADR (0.6%(38/5962) vs 1.4%(44/3061); p< 0.0001) and CSSDR (0.7% (49/7368) vs 2.0% (33/1655); p < 0.0001). An SSPDR of 2% had a lower hazard for PCCRC (HR=0.54 95% CI: 0.33-0.88) during the 6-60 month period. SSPDR of 2% was more protective for the 6-36 month period (HR=0.37 95% CI: 0.18-0.74). The results were similar for 1st event subset, CSSDR of 7% and ADR 25% (Table 1).

Discussion: Our novel data showing a lower HR for an SSPDR of 2% or higher support its use as a benchmark. However, CSSDR, with a similar HR, may be more practical due to pathological challenges in differentiating HPs versus SSPs.



Disclosures:


Joseph Anderson, MD¹, William Hisey, MS², Todd Mackenzie, PhD³, Christina Robinson, MS⁴, Lynn Butterly, MD². P1307 - Sessile Serrated Polyp Detection Rate of 2% or Greater Is Associated With a Lower Risk for Post-Colonoscopy Colorectal Cancer, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.