Resection depth and layer of cold snare polypectomy versus endoscopic mucosal resection

Cold snare polypectomy (CSP) has not undergone sufficient histopathological evaluation. This study aimed to clarify the histopathological features of CSP specimens, including resection depth and layer, as compared with endoscopic mucosal resection (EMR).

Polyps were recruited retrospectively. Sessile, semi-pedunculated, and 0-IIa polyps of ≤ 9 mm were selected by propensity score matching and classified as either a complete resection or one with an unevaluable/positive (X/+) margin. Resection depth and layer were estimated and the risk factors for an X/+ margin were evaluated.

A total of 1072 polyps were enrolled. After matching, 184 polyp pairs were selected. An X/+ margin was seen in 105/184 (57%) vs. 70/184 (38%) CSP vs. EMR specimens (p < 0.001): specimen damage was 53/184 (29%) vs. 30/184 (16%) (p < 0.01) and vertical margin (VM) X/+ was 11/184 (6%) vs. 2/184 (1%) (p < 0.05). Among 193 completely resected specimens, resection depth from the muscularis mucosae in CSP vs. EMR was 76 vs. 338 µm (p < 0.001) and resection layer was the submucosa in 7/79 (9%) vs. 105/114 (92%) (p < 0.001). In multivariate analysis, CSP was a risk factor for procedure-associated VMX/+ [odds ratio (OR) 6.80, 95% confidence interval (CI) 1.33–34.69, p < 0.05]. Sessile serrated adenoma/polyp (SSA/P) was a risk factor for VMX/+ margin in CSP specimens (OR 58.36, 95% CI 7.45–456.96, p < 0.001).

SSA/P and colorectal cancer may not be suitable for CSP adoption.