Mo1734 EFFICACY AND SAFETY OF UNDERWATER ENDOSCOPIC MUCOSAL RESECTION IN COMPARISON TO CONVENTIONAL EMR FOR THE REMOVAL OF COLON POLYPS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract

Underwater endoscopic mucosal resection (U-EMR) is an alternative technique to conventional EMR for resection of colorectal polyps. It has been postulated that in a water-filled colon, the mucosa and submucosal layers float away from the deeper layers assisting with easier resection of colorectal polyps. Outcomes of studies comparing with conventional EMR (C-EMR) have been variable. An electronic database search was conducted (PubMed, Embase, Google Scholar and Cochrane) for eligible articles comparing outcomes of U-EMR with conventional EMR for colorectal polyps resection. The primary outcomes were: Technical success rate defined as the rate of successful macroscopic resection of the polyp and residual polyp rates at the first follow up colonoscopy. Secondary outcomes were: En-bloc endoscopic resection of polyp in one piece and adverse event rates including immediate bleeding, delayed bleeding and perforation. Pooled rates and odds ratios (OR) were expressed as proportions of events over total patients (%) with 95% confidence limits with heterogeneity (I2) and p-value of <0.05 for significance. Eight studies (3 randomized controlled trials) were included in the final analysis. There were 869 polyps resected by U-EMR technique (mean age: 65.8 +/- 4.9 years, 61.2% males) and 930 polyps resected by C-EMR (mean age: 65.8 +/- 2.5, 63.2% males). The mean size of the polyps in U-EMR and C-EMR were 23.4 +/- 4.1 mm and 24.3 +/- 5.3 mm respectively. Polyps located in the proximal colon were 53.2% and 56.1% respectively for U-EMR and C-EMR. The technical success was 99.1% (95% CI: 98.4% - 99.8%) in U-EMR and 98.1% (95% CI: 96.4% - 99.8%)for C-EMR with OR of 1.61 (95% CI: 0.67 – 3.87, I2 – 37%). The residual polyp rate (5 studies) for UEMR was 8.2% (95% CI: 2.8% - 13.7%) and C-EMR was 23.1% (95 CI: 14% - 32.1%) with an odds ratio of 0.38 (95% CI: 0.22 – 0.66, I2 – 5%), significantly lower for UEMR (Figure 1). En-bloc resection rate (6 studies) was 68.5% (95% CI: 53.3% - 83.7%) in U-EMR and 58.7% (95% CI: 38% - 78.4%)for C-EMR with OR of 2.37 (95% CI: 1.14 – 4.95, I2 – 84%), significantly higher for U-EMR. There was no difference in immediate and delayed bleeding rates or perforation rates between the two groups (Figure 2). Sub-group analysis for RCTs showed significantly higher en-bloc resection rate for UEMR but similar rates of technical success and adverse events. This systematic review and meta-analysis shows a significantly lower residual polyp rate (5.4%) associated with U-EMR compared with C-EMR. In addition, there was a high rate of technical success (99%) and significantly higher en-bloc resection rate(68.5%). The rate of adverse events were comparable to C-EMR.View Large Image Figure ViewerDownload Hi-res image Download (PPT)