Annual Scientific Meeting
Introduction: Safe and effective resection of large colonic polyps remains a challenge for the practicing endoscopist. Recently, an underwater technique for endoscopic mucosal resection (UEMR) has emerged as an alternative to conventional injection-assisted EMR (CEMR). While the effectiveness of UEMR technique seems to be borne out in several case series and retrospective analyses, prospective data regarding its performance against CEMR technique is lacking.
Methods: This study was a prospective international multicenter randomized controlled trial involving 4 tertiary referral centers, 3 in the US and 1 in Italy, in order to compare the outcomes and safety of UEMR versus CEMR technique for large colon polyps (15mm or larger). Block randomization was used to assign patients to either the UEMR arm or CEMR arm. Primary outcome was the rate of curative resection, as documented by presence of residual neoplasia on 3-6 month surveillance colonoscopy. Secondary outcomes included resection time, total procedure time, en bloc resection rates, and adverse events.
Results: A total of 303 patients with 303 lesions were enrolled in this trial. 145 patients were randomized into the CEMR arm, and 158 patients were enrolled in the UEMR arm. Among those in the CEMR arm, 13 patients crossed over into the UEMR arm at the discretion of the performing endoscopist. Among those in the UEMR arm, 1 patient crossed over to the CEMR arm. At follow up, a total of 95 patients had surveillance colonoscopy performed in the CEMR arm, with residual neoplasia found in 16 of these patients (16.8%). In the UEMR arm, 118 patients followed up, with residual neoplasia found in 10 of these patients (8.5%) [p=0.06] The resection time and total procedure time were found to be less in the UEMR arm and there was a significantly higher rate of en bloc resection achieved by UEMR versus CEMR (P< 0.01). There was no difference in the rate of adverse events.
Discussion: This large multicenter randomized study supports that UEMR technique is a safe and effective alternative to CEMR technique and should be considered a first line option in the management of large laterally spreading colorectal tumors.