Implementation of Underwater Endoscopic Mucosal Resection for Colorectal Polyps at a Tertiary Center in Sweden

Aims Underwater endoscopic mucosal resection (uEMR) enables larger en bloc resections compared to conventional EMR, making it a valuable addition to the advanced polypectomy toolkit. Sahlgrenska University Hospital/Östra, is a tertiary center for colorectal polypectomy in Western Sweden (approximately 1.7 million residents). Between 350-450 advanced polypectomies are performed at our center annually. In 2023 we introduced uEMR, which was primarily performed by two experienced endoscopists, each skilled in both conventional and piecemeal EMR. Each case was reviewed in a multidisciplinary team meeting before selecting a resection technique. The aim of our study is to report data and insights from the first year of uEMR implementation at a Swedish tertiary center.

Methods Since 2019, all advanced polypectomy procedures performed at Sahlgrenska University Hospital/Östra have been registered in a prospective database. We conducted a retrospective review of all uEMR cases performed in 2023.

Results A total of 95 uEMR cases were reviewed. The median patient age was 71 years, with a median polyp size of 30 mm (IQR: 25-45mm) and a median SMSA score of 13 (IQR: 11-15). Most polyps were classified as Paris 0-IIa (51.6%), JNET 2A (58.9%) and located in the right colon (ascending colon and caecum, 64.2%). A total of 7,4% of the patients were treated with ASA and 23.2% were on anticoagulant therapy. Complications included intraoperative bleeding in 7.4% (n=7) and perforation in 5.3% (n=5) of the cases. Two cases required surgery due to concomitant bleeding and perforation which was not amenable to endoscopic therapy. All other complications were managed endoscopically. Delayed bleeding occurred in one case, and no delayed perforations were observed. Technical success was achieved in 97.9%, with en bloc resection and R0 resection rates of 46,3% and 40%, respectively. The largest en bloc resection measured 80 x 60mm, and the largest piecemeal resection measured 120 x 80mm. Early recurrence (within 6-12 months) was observed in 2 out of 50 cases. Adenocarcinoma was diagnosed in 5.3% of cases (n=5), with three requiring additional surgery due to high-risk histopathological features.

Conclusions The implementation of uEMR at a tertiary center with experienced endoscopists demonstrated high technical success rate (97.9%) and en bloc resection rates (46.3%), despite resection of large, complex lesions with high SMSA scores. Although complication rates were higher than those reported in the literature, they occurred during the early adoption phase of a novel technique.

Publication History

Article published online:
27 March 2025