Rajat Garg, MD1, Amandeep Singh, MD2, Babu P. Mohan, MBBS, MD3, Gautam Mankaney, MD2, Miguel Regueiro, MD1, Prabhleen Chahal, MD1; 1Cleveland Clinic Foundation, Cleveland, OH; 2Cleveland Clinic, Cleveland, OH; 3University of Utah, Salt Lake City, UT
Introduction: Underwater endoscopic mucosal resection (UEMR) for colorectal polyps has been reported to have good outcomes in recent studies. We conducted a systematic review and meta-analysis studying efficacy and safety of UEMR as compared to conventional EMR (CEMR). Methods: A comprehensive search of multiple databases (through May 2020) was performed to identify studies that reported outcome of UEMR and CEMR for colorectal lesions. Odds ratio was calculated for outcomes comparing CEMR and UEMR. Outcomes assessed included adverse events, intra-procedural bleeding, delayed bleeding, perforation, post-polypectomy syndrome, incomplete resection, en bloc resection, R0 resection and rate of recurrence amongst UEMR and CEMR. Subgroup analysis was performed for non-pedunculated polyps ≥10 mm and ≥20 mm. All analysis was performed using RevMan 5.0 (Cochrane Collaboration). Results: A total of 1,651 patients with 1,704 polyps were included from 9 studies. The mean age and polyp size ranged from 62.3 to 70 years and 9.9 mm to 30.2 mm, respectively. 66.4% of patients were males. Adverse events were 91 (10.2%) in CEMR group and 59 (7.2%) in UEMR group. Compared to CEMR, overall complications (odds ratio [OR]: 0.61 (95% CI, 0.42 – 0.88) (p=0.009), and intra-procedural bleeding (OR: 0.54, 95% CI, 0.36- 0.81, p=0.003) was significantly lower with UEMR (Figure 1a and 1b). There was also a significantly lower rate of incomplete resection (OR: 0.19 (95% CI, 0.05 -0.78, p=0.02) and polyp recurrence (OR: 0.41, 95% CI, 0.24 -0.72, p=0.002) after UEMR (Figure 2a and 2b). Odds of R0 resection were significantly higher in UEMR as compared to CEMR with OR of 2.20 (95% CI, 1.26 -3.83, I2=0, p=0.0005) (Figure 2c). There were 1,204 polyps ≥10 mm (612 CEMR and 592 UEMR), and 294 polyps (166 CEMR and 128 UEMR) were ≥ 20 mm. The recurrence rate was lower for non-pedunculated polyps ≥10 mm (OR 0.24, 95% CI, 0.10 -0.57, p=0.001) and ≥20 mm (OR 0.14, 95% CI, 0.02 -0.72, p=0.01). The rate of en bloc resection, delayed bleeding, perforation and post-polypectomy syndrome were similar in both groups (p >0.05). All results along with subgroup analysis are summarized in Table 1. Discussion: In this systematic review and meta-analysis, we found that UEMR is safer and more effective than CEMR with lower rates of adverse events and recurrence. UEMR use should be encouraged over CEMR.
Figure 1: Forest plot showing odds ration of any complication (A) and intra-procedural bleeding (B) comparing conventional endoscopic mucosal resection and underwater endoscopic mucosal resection.
Figure 2: Forest plot showing odds ratio of incomplete resection (A), R0 resection (B) and recurrence (C) comparing conventional endoscopic mucosal resection and underwater endoscopic mucosal resection.
Table 1: All Results along with subgroup analysis of non-pedunculated polyps ≥ 10 mm and ≥20 mm comparing underwater and conventional endoscopic mucosal resection.
Disclosures: Rajat Garg indicated no relevant financial relationships. Amandeep Singh indicated no relevant financial relationships. Babu Mohan indicated no relevant financial relationships. Gautam Mankaney indicated no relevant financial relationships. Miguel Regueiro indicated no relevant financial relationships. Prabhleen Chahal indicated no relevant financial relationships.