Scott R. Douglas, MD1, Leland Stratton, MD2, Ross C. Buerlein, MD1, James Patrie, MS2, Vanessa M. Shami, MD, FACG3, Bryan Sauer, MD, MSc (Clin Res)1, Cynthia Yoshida, MD2, Andrew Copland, MD3, James Scheiman, MD, FACG1, Dushant Uppal, MD1, Daniel Strand, MD1, Andrew Y. Wang, MD, FACG1
1University of Virginia, Charlottesville, VA; 2University of Virginia Health System, Charlottesville, VA; 3University of Virginia Digestive Health Center, Charlottesville, VA
Introduction: Underwater endoscopic mucosal resection (UEMR) is an alternative to conventional submucosal-lift EMR (CEMR) for removal of large non-pedunculated colorectal polyps. Retrospective studies have suggested that UEMR may be more effective at reducing lesion recurrence than CEMR, when performed by experts in this technique. The aim of this study was to compare the generalized safety and effectiveness of UEMR to CEMR for removal of large colorectal polyps when performed by expert endoscopists at a tertiary referral center.
Methods: Patients who had UEMR or CEMR performed by one of 7 experienced endoscopists ( >50 large polyp resections/year) at a single university-based health system between 3/2015 and 7/2018 were included. Each of the 7 endoscopists regularly performed CEMR but adopted UEMR before or during this study. Patients were identified retrospectively using CPT codes and data was collected from our electronic medical record.
Results: 186 patients who underwent 142 UEMR and 98 CEMR procedures were included (Table 1). Mean size of polyps removed was 30.7 mm (range: 15-120 mm) for UEMR and 25.3 mm (range: 15- 50 mm) for CEMR (P=0.001). There were a significantly greater number of tubulovillous adenomas in the UEMR group (22% vs. 37%, P=0.02). For polyps ≥4 cm, the residual polyp rate on the first follow-up colonoscopy was 26% for UEMR and 60% for CEMR (OR 4.2, P=0.05), as confirmed by biopsies. However, there was no statistically significant difference between UEMR vs. CEMR for lesion recurrence for polyps < 4 cm in size. For all polyp sizes, there was no difference in rates of complete macroscopic resection, en bloc resection, number of colonoscopies to reach clearance, and need for adjunctive resection techniques (i.e., argon plasma coagulation, hot biopsy avulsion) between the groups (Table 2). There were no instances of perforation. No significant differences in rates of intra-procedural or delayed procedural bleeding were found between groups (Table 3).
Discussion: When generalized across multiple endoscopists at a university-based health system, there was no observed benefit of UEMR compared to CEMR for colorectal polyps under 4 cm in size. However, for lesions 4 cm and greater, UEMR was superior in terms of reduced rates of residual lesion at the first follow-up colonoscopy. Prospective trials are required to further delineate the comparative impact of UEMR vs. CEMR with respect to rates of residual neoplasia.
Citation: Scott R. Douglas, MD; Leland Stratton, MD; Ross C. Buerlein, MD; James Patrie, MS; Vanessa M. Shami, MD, FACG; Bryan Sauer, MD, MSc (Clin Res); Cynthia Yoshida, MD; Andrew Copland, MD; James Scheiman, MD, FACG; Dushant Uppal, MD; Daniel Strand, MD; Andrew Y. Wang, MD, FACG. P0571 - UNDERWATER ENDOSCOPIC MUCOSAL RESECTION MAY ONLY BE SUPERIOR TO CONVENTIONAL ENDOSCOPIC MUCOSAL RESECTION FOR THE TREATMENT OF COLORECTAL POLYPS 4 CM OR LARGER. Program No. P0571. ACG 2019 Annual Scientific Meeting Abstracts. San Antonio, Texas: American College of Gastroenterology.