Impact of cumulative time on the clinical outcomes of endoscopic submucosal dissection in gastric neoplasm

Endoscopic submucosal dissection (ESD) can be technically demanding and requires great attention to detail and prolonged concentration. We assumed that clinical outcomes of ESDs may be affected by cumulative time, and we aimed to compare complete resection rates and adverse events according to cumulative ESD time. This study involved 1,328 consecutive patients with 1,461 gastric tumors who underwent ESD from January 2008 to July 2011 in a tertiary-care academic medical center. The main outcome measurements were en bloc resection rate, complete resection rate, bleeding rate and perforation rate. Patients were divided into three groups according to cumulative time intervals (< 2 h vs. 2-4 h vs. a parts per thousand yen4 h). Complete resection rate did not differ among the three groups, but early post-ESD bleeding (EPEB) rate was significantly different among the three groups (2.5 vs. 3.5 % vs. 6.6 %, P = 0.040). In multivariate analysis, cumulative time period was an independent predictor of EPEB (2-4 h odds ratio [OR] 2.29, 95 % confidence interval [CI] 1.05-5.01, P = 0.038; a parts per thousand yen4 h OR 3.99; 95 % CI, 2.15-7.65, P < 0.001). The rate of perforation was higher in ESDs performed after completing prior endoscopies or outpatient clinic session compared to those performed without prior work (3.8 vs. 1.6 %, P = 0.004). Moreover, prior workload before ESD was an independent predictor of perforation in multivariate analysis (OR 2.77, 95 % CI, 1.37-5.60, P = 0.005). Our data suggest that cumulative ESD time did not influence en bloc or complete resection rate of ESD, but increased the rate of acute bleeding. Moreover, prior workload before ESDs may increase the risk of perforation.