Underwater Resection of Non-pedunculated Colorectal Lesions

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.

Inclusion Criteria:

- Adult (≥18 years old) male and female patients.

- Scheduled for outpatient colonoscopy.

- Patient able to provide informed consent.

- Benign, small (6-9mm) and large (≥1cm) non-pedunculated colorectal lesions.

Exclusion Criteria:

- Diminutive (≤5mm) and pedunculated polyps.

- Lesions suspected of harboring deep submucosal invasion.

- Patients who decline to participate or are unable to provide informed consent.