Factors associated with technical difficulty of endoscopic submucosal dissection for early gastric cancer that met the expanded indication criteria: post hoc analysis of a multi-institutional prospective confirmatory trial (JCOG0607)

There are few reports on the technical difficulty of gastric endoscopic submucosal dissection (ESD). The aim of this study was to investigate the factors associated with the technical difficulty of ESD for early gastric cancer (EGC) using the data from the multicenter non-randomized confirmatory trial of expanded indication criteria of ESD (JCOG0607).The major inclusion criteria were as follows: (1) histologically proven intestinal-type adenocarcinoma; (2) cT1aN0M0; (3) lesion without finding of ulcer (UL-negative) with 2 cm in size, or UL-positive with ≤ 3 cm; (4) age 20-75 years. The difficult case was defined as ESD taking ≥ 120 min, piecemeal resection, and/or developing perforation during procedure.Between June 2007 and October 2010, 470 patients were enrolled from 29 institutions. Median procedure time was 79 (range 14-462) min, and it was ≥ 120 min in 127 patients. Twelve patients developed perforation during ESD, and the procedure time was ≥ 120 min in 9 of them. Therefore, 130 patients (27.7%) were identified as difficult cases. Multivariable analysis showed that UL-negative with 5 cm (vs. UL-negative with ≤ 3 cm, odds ratio, 24.993; 95% CI 6.130-101.897, p 0.0001) had the largest odds ratio and followed by UL-negative with 3-5 cm upper or middle portion of stomach and age ≤ 60 years were significantly associated with difficulty.UL-negative lesion with 3 cm, upper or middle portion of stomach and age ≤ 60 years were independent factors associated with technical difficulty of ESD for EGC. Trial registered number was UMIN000000737.