Prediction of technically difficult endoscopic submucosal dissection for large superficial colorectal tumors: a novel clinical score model

Abstract Background and Aims Endoscopic submucosal dissection (ESD) is a promising technique for removing superficial gastrointestinal tumors, but ESD is technically difficult. The aims of this study were to establish a clinical score model for grading technically difficult colorectal ESD (CR-ESD). Methods Data on patients, lesions, and outcomes of CR-ESD at 2 centers were analyzed. The objective parameter of successful ESD within 60 minutes was set as an end point to evaluate the difficulty. Independent predictors of difficulty in the derivation cohort were identified by multiple logistic regression analysis and used to develop a clinical score. We validated the score model in the validation cohort. Results The clinical score comprised the following: tumor size of 30 to 50 mm (1 point) or ≥50 mm (2 points); ≥2/3 circumference of the lesion (2 points); location in the cecum (1 point); flexure (2 points) or dentate line (1 point); and laterally spreading tumor non-granular lesions (1 point). Areas under receiver-operator characteristic curves for the score model were comparable (derivation [0.70] vs internal validation [0.69] vs external validation [0.69]). The probability of successful ESD within 60 minutes in easy (score = 0), intermediate (score = 1), difficult (score = 2-3), and very difficult (score ≥4) categories were 75.0%, 51.3%, 35.6%, and 3.4% in the derivation cohort, 73.3%, 47.9%, 31.8%, and 16.7% in the internal validation cohort, and 79.5%, 66.7%, 43.3%, and 20.0% in the external validation cohort, respectively. Conclusions This clinical score model accurately predicts the probability of successful ESD within 60 minutes and can be applied to grade the technical difficulty before the procedure.