Colorectal endoscopic submucosal dissection (ESD) performed by experienced endoscopists with limited experience in...

Since colorectal endoscopic submucosal dissection (ESD) requires higher-level skills than endoscopic mucosal resection (EMR), it is recommended to acquire sufficient experience in gastric ESD prior to attempting colorectal ESD. We evaluated the ability of experienced endoscopists with limited experience in gastric ESD to perform colorectal ESD.

We retrospectively reviewed 120 colorectal ESDs performed by two endoscopists who had expertise in colonoscopy and colorectal EMR but experience of fewer than five gastric ESDs. Main outcomes were the en bloc resection rate with tumor-free margins (R0 resection rate) and adverse events rate. Using only clinical characteristics prior to ESD, we also identified factors affecting outcomes.

A total of 113 patients (94.2 %) received en bloc resection, and the R0 resection rate was 80.0 % (96/120). Perforation and postoperative hemorrhage occurred in eight (6.7 %) and two (1.7 %) patients, respectively. Dividing the 120 cases into three learning phases, R0 resection and perforation rates improved from 77.5 % (31/40) and 12.5 % (5/40) in phase 1 to 85.0 % (34/40) and 2.5 % (1/40) in phase 3, respectively. Multivariate analysis revealed that lesions at junctions (dentate line, sigmoid-descending junction, splenic flexure, hepatic flexure, ileocecal valve) and lesions with factors reflecting fibrosis in the submucosal layer (based on endoscopic findings before ESD) were significantly correlated with R0 resection failure, with adjusted odds ratios of 10.5 (95 % CI 2.1-67.6) and 10.4 (2.7-48.6), respectively.

Colorectal ESD is feasible for experienced endoscopists with limited experience in gastric ESD. Novices should avoid lesions at junctions or those with factors reflecting fibrosis.