Single Center Experience With Endoscopic Mucosal Resection for Large Colonic Polyps: How Do We Compare to Larger Studies in Terms of Efficacy and Safety?

Introduction: Endoscopic mucosal resection (EMR) is a well described and safe technique, predominantly used for removal of large colonic lesions ( >1cm) within superficial layers of the mucosa. Prior studies have suggested a recurrence rate of 15%-30% post-EMR. In this study, we evaluated the efficacy and safety of EMR at our institution and compared this to that of previous multicenter studies. Methods: A single center, retrospective analysis was conducted to evaluate outcomes of all patients referred to our advanced endoscopy center for EMR, between 2012-2020. Of the 333 patients identified, 199 were excluded due to lack of colonoscopy follow-up, 6 were excluded due to undergoing surgery following initial EMR, and 3 were excluded due to failed EMR attempt. Patient demographics (age, gender), polyp characteristics (pathology, size, colon location), and EMR technique (piecemeal vs en bloc polyp removal, use of bipolar cautery or APC) were recorded. Patients with residual disease at the site of prior EMR during surveillance colonoscopy underwent removal of the recurrent polyp and were classified as recurrent. Statistical analyses were performed using Wilcoxon Rank sum for continuous variables and Chi-Squared Fisher’s Exact for categorical variables. Results: A total of 125 patients were included in the study. We found the average time to surveillance colonoscopy after initial EMR was 10 months, and the recurrence rate following initial EMR was 15.2%. Male gender and polyps in the appendiceal orifice were associated with a higher risk of recurrence post-EMR (HR 4.19 and 6.94, respectively). Tubulovillous adenomas trended towards a higher risk of recurrence post-EMR (HR 2.98). However, polyp removal in piecemeal fashion (vs en bloc resection), bipolar cautery or APC following EMR, and polyp size were not associated with an increased risk of recurrence. Average time to surveillance following retreatment of residual polyp was 12.6 months. Of those who underwent retreatment, 15.7% had recurrence, 47% did not have evidence of recurrence, 15.7% failed to show up, and 21% were not due for surveillance at the conclusion of the study Conclusion: We found that EMR is an effective and safe method for removal of large colonic polyps, frequently reducing the need for surgical intervention. However, improved education regarding the importance of post-EMR surveillance is needed as nearly 60% of our patients failed to have repeat colonoscopy.Table 1.: Risk Factors for Polyp Recurrence Post-EMR.