Predictors of technical difficulty for trainees in esophageal endoscopic submucosal dissection.

Background: Esophageal endoscopic submucosal dissection (ESD) is technically challenging, especially for trainees, and requires a safe training system. This study aimed to identify predictors of technical difficulty facing trainees performing esophageal ESD to establish such system.

Methods: This was a single-center retrospective study of patients with esophageal cancer who underwent ESD performed by trainees between January 2010 and August 2022. Technical difficulties were defined as muscularis propria exposure and long procedure time (≥ 90 min). Factors associated with these technical difficulties were investigated.

Results: A total of 798 lesions in 721 patients were evaluated. Muscularis propria exposure occurred in 298 lesions (37.3%), including 10 perforations (1.3%). The procedure time was ≥ 90 min in 134 lesions (16.8%). In the multivariate analysis, tumor size ≥ 20 mm, tumors ≥ 1/2 of the circumference, and those close to previous treatment scars significantly increased the incidence of both difficulties, whereas tumors in the upper esophagus significantly decreased this incidence. Furthermore, female sex and tumors in the left wall were independent predictors of muscularis propria exposure, and elevated morphology was an independent predictor of long procedure time. Muscularis propria exposure and long procedure time occurred in more than half of the cases with three or more predictors of each difficulty.

Conclusions: Large tumors and tumors close to previous treatment scars increase technical difficulties for trainees in esophageal ESD. Conversely, tumors in the upper esophagus reduce these difficulties. These results enable us to predict the difficulty level preoperatively and select appropriate cases in stepwise training.