LEARNING CURVE IN COLONIC ENDOSCOPIC SUBMUCOSAL DISSECTION: A COMPREHENSIVE META-ANALYSIS

BACKGROUND AND AIMS:
Endoscopic submucosal dissection (ESD) represents a minimally invasive, endoscopic curative resection technique for foregut and hind gut submucosal pathology. Despite its potential, ESD poses a significant challenge with a steep learning curve, compounded by the absence of comprehensive meta-analyses addressing this curve.

METHODS:
A systematic search of electronic databases from January 1997 through November 2023 identified 650 studies. After rigorous review, 75 relevant articles were considered, with data extraction from 17 studies (N=4,745) meeting inclusion criteria. Pooled proportions were calculated using fixed and random-effects models, with a 95% confidence interval (C.I.). Proficiency was defined by using the benchmark of greater than 90% en bloc resection rate, greater than 80% resection rate and greater than 9 cm²/h resection speed.

RESULTS:
The analysis included lesions in the right colon (37.84%), left colon (23.76%), and rectum (35.21%). Among 4,745 cases, 78.90% involved men, with a mean age of 66.43 years (SD= 2.81). Notably, 47.62% of endoscopists were experts, while 52.38% were trainees. Proficiency in ESD was achieved after 61.21 procedures (95% CI: 26.17-96.25), with a mean procedure duration of 97.02 minutes (95% CI: 83.07-110.97) and a mean dissection speed of 9.43 mm²/min (95% CI: 10.97-7.88). Malignant pathology comprised 49.62% of lesions, with EN bloc resection and R0 resection rates of 91.96% and 83.87%, respectively. The overall adverse event rate was 6.82% (95% CI: 6.12-7.55) [Figure 1], including perforation (4.22%, 95% CI: 3.67-4.81) and bleeding (2.41%, 95% CI: 1.99-2.86). No significant difference in dissection speed was observed between experts and trainees. However, the trainee group exhibited higher adverse event rates (7.63% vs. 6.29%) and bleeding rates (+1.17%, 95% CI: 1.05-2.23). Egger bias indicator yielded a bias value of 1.17 (p=0.12) [Figure 2].

CONCLUSIONS:
Our analysis reveals proficiency in colonic ESD is achieved after approximately 61 procedures, with a mean dissection speed of 97 minutes and an overall adverse event rate of 6.82%. Expert practitioners demonstrated lower adverse event and bleeding rates compared to trainees. These findings can inform endoscopy scheduling, educational planning, and competency evaluations within ESD training programs. Future research and randomized trials should continue to investigate the learning curve of ESD.