Underwater polypectomy without submucosal injection for colorectal lesions ≤ 20 mm in size—a multicenter retrospective observational study

BACKGROUND: Underwater polypectomy (UWP) of large (≥20mm) colorectal lesions is well described, but reports of UWP for lesions ≤20mm in size, which account for >95% of polyps encountered in routine clinical practice, are limited. We assessed the feasibility of UWP in routine practice across various sites for colorectal lesions ≤20mm in size. METHODS: A multicenter retrospective study was performed on pooled data from 9 colonoscopists at 3 U.S., 1 Taiwanese and 2 Italian sites. Outcomes related to UWP on lesions ≤20mm in size were analyzed. RESULTS: In 117 patients, UWP netted 169 lesions. Polypectomy by hot (HSP, 54%) or cold (CSP, 41%) snare, and cold forceps (CFP, 5%) were performed successfully without endoscopic evidence of residual neoplasia or immediate clinically significant adverse events. The majority (74.6%) were tubular adenomas; 60.9% were from the proximal colon. Histopathologic margins were positive in 4 and unavailable in 26 CSP and 24 HSP specimens. The remainder had negative resection margins on pathologic reports. CONCLUSION: UWP for colorectal lesions ≤20mm in routine practice across multiple sites confirms the feasibility and acceptability of this technique. Improvement of resection outcomes by UWP in routine practice deserves further evaluation in a randomized controlled trial.