Supplementary Material for: EndoTrac-assisted vs conventional ESD in superficial gastric neoplasms: A multicenter randomized controlled trial

Background and Aims: Endoscopic submucosal dissection (ESD) is a technically demanding curative treatment for early gastric cancer. The EndoTrac traction device was designed to enhance maneuverability during ESD. This study evaluated whether EndoTrac-assisted ESD (ET-ESD) improves outcomes versus conventional ESD (C-ESD) in patients with superficial gastric neoplasms. Methods: In this multicenter, single-blind, randomized controlled trial, 142 patients from 11 Japanese centers were assigned to undergo ET-ESD (n=72) or C-ESD (n=70). The primary endpoint was ESD procedure time. Secondary endpoints included efficacy, safety, and device-related outcomes. Operator experience, lesion characteristics, knife type, and institutional ESD volume were recorded and analyzed. Results: Median procedure times were 53.5 minutes for ET-ESD and 57.0 for C-ESD (P=0.56). Among trainees, ET-ESD was associated with a shorter procedure time than C-ESD (59.0 vs. 85.5 minutes; P=0.02). In subgroup analyses of trainee cases, shorter times with ET-ESD were associated with several scenarios (e.g., lesions ≤20 mm, upper/middle third of the lesser curvature, needle-type knife, and low-volume centers). In a multivariable analysis among trainees, ET-ESD remained independently associated with shorter procedure time (B= -24.8 minutes; 95% CI, -43.8 to -5.8; P=0.012). In the overall cohort, en bloc and R0 resection rates, adverse events, and device-related complications were similar between groups. Conclusions: ET-ESD did not significantly shorten procedure time in the overall cohort. Nonetheless, exploratory subgroup analyses suggested potential benefits among trainees, small lesions, technically challenging locations, and low-volume centers.