Underwater endoscopic mucosal resection: The third way for en bloc resection of colonic lesions?

Background Underwater endoscopic mucosal resection without submucosal injection has been described for removing large flat colorectal lesions. Objective We aim to evaluate the reproducibility of this technique in terms of ease of implementation, safety and efficacy. Methods A prospective observational study of consecutive underwater endoscopic mucosal resection in a community hospital was performed. Results From September 2014 to April 2015, 25 flat or sessile colorectal lesions (median size 22.8mm, range 10-50mm; 18 placed in the right colon) were removed in 25 patients. Two of the lesions were adenomatous recurrences on scar of prior resection and one was a recurrence on a surgical anastomosis. The resection was performed en bloc in 76% of the cases. At the pathological examination, 14 lesions (56%) had advanced histology and seven (28%) were sessile serrated adenomas (two with high-grade dysplasia). Complete resection was observed in all the lesions removed en bloc. Intra-procedural bleeding was observed in two cases; both were managed endoscopically and were uneventful. No major adverse events occurred. Conclusion Underwater endoscopic mucosal resection appears to be an easy, safe and effective technique in a community setting. Further studies evaluating the efficacy of the technique (early and late recurrence), as well as comparing it with traditional mucosal resection, are warranted.