S273 Two Withdrawals During Colonoscopy Are Better Than One in Lynch Syndrome: A Systematic Review and Meta-Analysis

Abstract

Introduction: Lynch syndrome is being increasingly diagnosed with wider availability of genetic testing and increasing prevalence of young-onset colorectal cancers. Missed adenomas are a particular concern because of high risk of interval colon cancers in Lynch syndrome. The aim of this study was to report on the adenoma detection rate (ADR) and adenoma miss rate (AMR) during first pass and second pass colonoscopy in patients with Lynch syndrome. Methods: Electronic literature search was performed using SCOPUS, MEDLINE, and COCHRANE LIBRARY (Inception to March 2021) for randomized controlled trials (RCT) of advanced imaging during colonoscopy in patients with Lynch syndrome. Inclusion criteria were: 1) history of genetically proven Lynch syndrome or satisfaction of the Amsterdam Criteria, 2) performance of tandem colonoscopies (either dye-based chromoendoscopy and white light endoscopy (WLE) or electronic chromoendoscopy and WLE, in any order) and 3) reporting of adenoma detection rate. Outcomes of interest were adenoma detection rates (ADR) of two versus one withdrawal and adenoma miss rates of one withdrawal. Pooled relative risk (RR) for outcomes of interest were analyzed using Review Manager version 5.3. Results: Of the 15 citations reviewed, six RCT were eligible. A total of 436 subjects (average age: 43.6 years, 55% females) underwent tandem examination of colon: dye-based chromoendoscopy (N = 267) and electronic chromoendoscopy (N = 261) alternating with WLE in any order. The two withdrawals had higher ADR compared to one withdrawal irrespective of the method of the initial withdrawal: pooled RR 1.67 (95% CI: 1.34-2.07; I2 = 0%) (Panel A). Comparing the yield of two withdrawals with only the first withdrawal, the adenoma miss rate of the first withdrawal was 64.7% (95% CI: 58.4%-70.5%; I2 = 22%) (Panel B). If the first withdrawal was dye-based chromoendoscopy, then the adenoma miss rate was lower compared to those patients where the first withdrawal was with electronic chromoendoscopy (36.8% versus 63.1%; pooled RR 1.68, 95% CI: 0.94-2.91; I2 = 85%). Conclusion: The adenoma miss rate of a single withdrawal during colonoscopy in patients with Lynch syndrome is greater than 50%. Endoscopists should consider performing a second withdrawal in this high-risk population.Figure 1.: A. Forest plot of ADR among subjects with colon examination by two withdrawals compared to single withdrawal using any modality. B. Forest plot of AMR of colon examination by single withdrawal when colon examination was performed with second withdrawal by any modality.