Effect of Administration of a Proton Pump Inhibitor for Ulcerative Differentiated Early Gastric Cancer Prior to Endoscopic Submucosal Dissection.

OBJECTIVES Predicting the depth of invasion for early gastric cancer (EGC) with ulcerative findings may prove difficult. The purpose of this study was to evaluate the extent of ulcer healing and clinical effectiveness of proton pump inhibitor (PPI) administration for ulcerative differentiated EGC prior to endoscopic submucosal dissection (ESD). METHODS A total of 214 patients with ulcerative differentiated EGC who were treated by ESD were retrospectively analyzed, among whom 129 had been administered a PPI prior to ESD and 85 patients had not. The degree of ulcer healing following administration of PPI and the clinical outcome were compared between the PPI and non-PPI groups. RESULTS The ulcer healing rate (80.7 vs. 30.6%, p<0.001) and complete ulcer healing rate (45.0 vs. 16.5%, p<0.001) differed significantly between the PPI and non-PPI groups, respectively. The ESD procedure time was 86.0 (73) vs. 100.0 (68.0) min (p=0.044). However, no significant differences were observed in the en bloc resection rate, complete resection rate, or the incidence of adverse events. Based on the multivariate regression analysis, PPI administration [odds ratio (OR)=4.909, 95% confidence interval (CI): 2.459-9.799, p<0.001] and mucosal cancer (OR=9.336, 95% CI: 2.693-32.362, p<0.001) were independent predictive factors for complete ulcer healing. Partial or complete ulcer healing following PPI administration had a better predictive ability than EUS for mucosal invasion (kappa value 0.553 vs. 0.101; Youden index 0.553 vs. 0.132). CONCLUSIONS Partial or complete ulcer healing following PPI administration predicts differentiated EGC that is confined to the mucosa.