P0272 - Estimating True Sessile Serrated Polyp Prevalence Based on Detection Rates of Top Performers

Peter H. Nguyen, MD¹, Daniel Kim, MD², Douglas Wang, BS³, William Karnes, MD^4
1University of California Irvine, Orange, CA; ²H. H. Chao Comprehensive Digestive Disease Center, University of California Irvine, Orange, CA; ³University of California Irvine, Irvine, CA; ⁴Digestive Health Institute, University of California Irvine Medical Center, Irvine, CA

Introduction: Sessile serrated polyps (SSP) are precursors to colorectal carcinoma (CRC), especially among interval CRCs. These polyps tend to be flat, with indistinct margins, making them challenging to find and remove. Current literature reports the prevalence of SSPs to be approximately 8% based on the average detection rate of SSPs1. True prevalence should equal to or exceed the SSP detection rate (SDR) of the top performing colonoscopist serving a population. To estimate the prevalence of SSPs in a population served by a large academic center in Southern California, we examined the SDRs of its colonoscopists.

Methods: Data was collected prospectively in the UCI Colonoscopy Quality Database between 2012 and 2019. We evaluated endoscopists who performed at least 150 screening and surveillance colonoscopies in patients over age 40. Statistical analyses were performed including Chi-squared test, ANOVA, and two-sample t-test.

Results: A total of 10 endoscopists were identified who met inclusion criteria. The top 3 endoscopists (C1, C2, C3) detected SSPs at a rate of 16% (95% CI 10.2-21.8), 14% (95% CI 11.2-16.2), and 14% (95% CI 12.5-15.5), respectively (Figure 1). These top 3 endoscopists found significantly more SSAs than endoscopists C7-C10 who had a SDR of 7% or less (p < 0.01). Between the 10 endoscopists, there were no significant differences in their patient population’s demographic characteristics: gender (X2 = 0.162, p = 0.999), ethnicity (X2 = 0.279, p = 0.999), or screening vs surveillance (X2 = 0.855, p = 0.999). However, there was a significant difference between the mean age across the 10 endoscopists with C1-3 having an average age of 3 years older than C7 (Age 63, 63, 62 vs 59, F = 22.963, p < 0.05).

Discussion: Our top performing endoscopists (C1, C2, and C3) were able to detect SSAs at a significantly higher rate that could not be explained by differences in patient population gender, ethnicity, and type of procedure. Based on these top performers and their unknown miss-rates of SSPs, we estimate the true prevalence of SSAs in our population to exceed 15%.

Reference:
1. IJspeert, Joep E G et al. “Prevalence, distribution and risk of sessile serrated adenomas/polyps at a center with a high adenoma detection rate and experienced pathologists.” Endoscopy vol. 48, 8 (2016): 740-6. doi:10.1055/s-0042-105436




Disclosures:


Peter H. Nguyen, MD¹, Daniel Kim, MD², Douglas Wang, BS³, William Karnes, MD⁴. P0272 - Estimating True Sessile Serrated Polyp Prevalence Based on Detection Rates of Top Performers, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.