S507 Higher Sessile Serrated Lesion Detection Rates Are Associated With Lower Risk for Post-Colonoscopy Colorectal Cancer: Data From the New Hampshire Colonoscopy Registry

Introduction: The adenoma detection rate (ADR) is inversely associated with post-colonoscopy colorectal cancer (PCCRC) incidence. Calculating ADR-A using data from colonoscopies for all indications, rather than screening exams alone (ADR-S), can provide rates which are easier to calculate and can mitigate gaming by endoscopists. We hypothesized that calculating sessile serrated lesion detection rates (SSLDR-A) using all exams may also be a quality metric for predicting PCCRC risk. Using New Hampshire Colonoscopy Registry (NHCR) data, we examined the association between SSLDR-A and PCCRC risk. We also compared SSLDR-A to all screening examinations (SSLDR-S). Methods: The cohort included NHCR 115,585 patients with an index colonoscopy. The primary outcome was PCCRC, defined as CRC diagnosed ≥6 months after the index colonoscopy. The exposure variables were endoscopist-specific SSLDR-A (calculated using all exams) and SSLDR-S (using screening exams), stratified into quintiles. Cox regression was used to model the hazard of PCCRC on SSLDR, adjusting for relevant covariates, such as patient age and sex. Results: The cohort included NHCR 115,585 patients with an index colonoscopy. There were 177 PCCRCs diagnosed. Higher SSLDR-A and SSLDR-S rates were associated with lower PCCRC risks. After adjusting for covariates, we observed that higher SSLDR-A rates were associated with lower hazard ratios (HR) as compared to the reference group (SSLDR-A: <1.5%; HR = 1.0 vs SSLDR-A: 1.5 to <3.0%; HR = 0.53, 95% CI 0.35-0.79; SSLDR-A: 3.0-<5.0%; HR = 0.59, 95% CI 0.38-0.92; SSLDR: 5.0-<8.0%; HR = 0.44, 95% CI 0.28-0.70; and SSLDR: 8.0+% HR = 0.20, 95% CI 0.08-0.46). The highest quintile of SSLDR-A (8.0%+) (HR = 0.20, 95% CI 0.08-0.46) and SSLDR-S (8.0%+) (HR = 0.20, 95% CI 0.09-0.44) provided similar protection from PCCRC. Comparing SSLDR-A and SSLDR-S, of 126 endoscopists sampled, most (74%) remained in the same quintile. Conclusion: These findings demonstrate that colonoscopies performed by endoscopists with higher SSLDR-A are associated with a lower risk of PCCRC, validating SSLDR-A as a quality metric. We observed that most endoscopists remained in the same quintile rank but about one-quarter moved to a different quintile, a proportion similar to that observed in similar ADR analyses. Furthermore, our data suggest that endoscopists should aim for a SSLDR-A of 8.0% or higher.