Conventional endoscopic resection of small and large (≥1cm) colorectal lesions is well established and performed with the colon fully distended with gas. Conventional polypectomy is effective, but the rate of incomplete resection is approximately 10%. Incomplete eradication of precancerous lesions contributes to interval colorectal cancer; therefore, alternative techniques for resection that safely and effectively increase the rate of complete resection are important. Underwater resection (UR) of benign colorectal lesions is a novel technique that utilizes the advantages of water aided endoscopic methods and may decrease the incomplete resection rate of small and large non-pedunculated lesions.~The investigators propose the hypothesis that small (6-9mm) and large (≥1cm) non-pedunculated neoplastic colorectal lesions resected by UR (partially distended, water filled lumen without submucosal fluid injection), will significantly decrease the incomplete resection rate (IRR) compared to conventional polypectomy performed in a gas distended lumen.~Small (6-9mm) and large (≥1cm) non-pedunculated benign neoplastic colorectal lesions identified during screening, surveillance, diagnostic or therapeutic colonoscopy will be randomized to conventional polypectomy (in a gas distended lumen with or without submucosal fluid injection) versus UR (partially distended, water filled lumen without submucosal injection) at the patient level. Small (6-9mm) lesions will be removed with a 9mm firm, thin wire cold snare and large (≥1cm) lesions will be removed by snare electrocautery. Efforts to remove lesions en bloc with a small rim of normal mucosa will be made, although some larger lesions (≥2cm) may require piecemeal resection. Submucosal fluid injection with a solution may be used with conventional techniques for large and/or flat lesions. Post-polypectomy incomplete resection rates will be assessed from 4 quadrant biopsies obtained around the resection site immediately post-resection.
The aim of this study is to compare the efficacy of underwater resection (polypectomy) versus conventional polypectomy techniques for small and large colorectal lesions identified during colonoscopy.