Endoscopic submucosal dissection (ESD) is an established treatment for superficial colorectal tumors. However, its technical difficulty varies according to lesion location, and right-sided colonic lesions often present poor scope maneuverability, making the procedure more challenging. We previously reported that balloon-assisted endoscopy (BAE) improves scope control in retrospective analyses. This randomized study aimed to compare balloon-assisted ESD (BAESD) with conventional ESD (CESD) for technically difficult right-sided colonic lesions.

This single-center prospective randomized controlled trial was conducted at Jichi Medical University Hospital. Patients with superficial right-sided colonic tumors (20–50 mm) judged to have poor maneuverability during preoperative colonoscopy were randomly assigned (1:1) to BAESD or CESD. The primary endpoint was the ESD completion rate. Secondary endpoints included procedure time, dissection speed, specimen size, en bloc resection rate, R0 resection rate, operator change, and complications. Analyses were performed on both an intention-to-treat (ITT) and per-protocol (PP) basis.

Thirty patients were enrolled (14 in the BAESD group and 16 in the CESD group). In the ITT analysis, the ESD completion rate was 100% (14/14) in the BAESD group and 75% (12/16) in the CESD group, showing a higher trend in favor of BAESD, although without statistical significance (P = 0.103). All incomplete CESD cases were successfully completed after conversion to BAESD. Procedure time (93 vs. 102 minutes), dissection speed (20.2 vs. 21.5 mm²/min), en bloc resection rate (100% in both groups), and R0 resection rate (93% vs. 88%) were comparable. One microperforation occurred in the BAESD group and was managed endoscopically; no delayed bleeding or severe complications were observed.

Although recent technical advancements such as traction devices and injectable knives have expanded the indications for colorectal ESD, scope maneuverability based on lesion location remains a key determinant of technical difficulty. While statistical significance was not reached, the 100% completion rate in the BAESD group and the successful completion of all CESD-interrupted cases after switching to BAESD are clinically meaningful. BAESD may facilitate complete ESD in technically difficult right-sided colonic lesions and represents a practical rescue strategy.