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

Background and Aim: 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. Methods: This retrospective study included consecutive patients who underwent Tip‐in EMR for 15–25 mm 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. Results: 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). Conclusion: The clinical outcomes of Tip‐in EMR for 15–25 mm lesions performed by non‐experts were favorable. [ABSTRACT FROM AUTHOR]