Clinical outcomes and learning curve of Tip-in endoscopic mucosal resection for 15-25mm colorectal neoplasms among non-experts.

Abstract

Tip-in endoscopic mucosal resection (EMR) has a high en bloc resection rate for large colorectal neoplasms. However, non-experts' performance in Tip-in EMR has not been investigated. We investigated whether Tip-in EMR can be achieved effectively and safely even by non-experts. This retrospective study included consecutive patients who underwent Tip-in EMR for 15-25mm colorectal nonpedunculated neoplasms at a Japanese tertiary cancer center between January 2014 and December 2020. Baseline characteristics, treatment outcomes, learning curve of non-experts, and risk factors of failing self-achieved en bloc resection were analyzed. A total of 597 lesions were analyzed (438 by experts and 159 by non-experts). The self-achieved en bloc resection (69.8% vs 88.6%, P<0.001) and self-achieved R0 resection (58.3% vs 76.5%, P<0.001) rates were significantly lower in non-experts with <10 cases of experience than in experts, but not in non-experts with >10 cases. Adverse event (P=0.165) and local recurrence (P=0.892) rates were not significantly different between experts and non-experts. Risk factors of failing self-achieved en bloc resection were non-polypoid morphology (OR 3.4, 95% CI 1.6-7.3, P=0.001), lesions with an underlying semilunar fold (OR 3.6, 95% CI 1.6-7.3, P<0.001), positive non-lifting sign (OR 3.1, 95% CI 1.2-8.0, P=0.023), and non-experts with an experience of ≤10 cases (OR 3.6, 95% CI 2.1-6.3, P<0.001). The clinical outcomes of Tip-in EMR for 15-25mm lesions performed by non-experts were favorable.