Learning curve for endoscopic submucosal dissection (ESD) in the United States: Large, untutored, single-operator experience.

Background and study aims Endoscopic submucosal dissection (ESD) allows removal of tumors en-bloc. Western adoption of ESD has been hindered by its steep learning curve. Western data regarding ESD learning curve are limited. We analyzed the learning curve of a single endoscopist at a tertiary referral center in the United States. Patients and methods All consecutive ESDs performed by a single endoscopist at a tertiary referral center in the United States from 2015 through 2022 were identified. Descriptive statistics and CUSUM analysis were used to describe the learning curve for en-bloc, R0 resection, and resection speed. Results In our study, 503 patients with 515 lesions were included. Severe submucosal fibrosis was found in 17% of the lesions. The rates of en-bloc, R0, and curative resections were 81.9%, 71.1%, and 68.4%, respectively. CUSUM analysis showed that the learning curve plateaued at 268, 347, and 170 cases for en-bloc resection, R0 resection, and achieving a resection speed > 9 cm 2 /hr. Fibrosis significantly affected the R0 resection rate in the regression analysis (95% confidence interval 0.21-0.55). In colonic ESD curve analysis, the learning plateau was reached after 185 cases for both en-bloc and R0 resection. Conclusions Following ex-vivo training in an animal model, an untutored expert operator achieved competency in ESD between 250 and 350 procedures. Our data can inform development of future training programs in the West.