OBJECTIVES:Helicobacter pylori (H. pylori) eradication is strongly recommended for gastric cancer patients who undergo subtotal gastrectomy. The efficacy of proton pump inhibitor-based triple therapy for H. pylori eradication has not been adequately assessed in the gastric remnant. The aim of this study was to compare the efficacy of postoperative versus preoperative H. pylori eradication therapy.METHODS:A total of 138 distal gastric cancer patients with H. pylori infection were randomized to receive either preoperative (preop, N = 68) or postoperative (postop, N = 70) proton pump inhibitor-based triple therapy for H. pylori eradication. The regimen consisted of rabeprazole 10 mg, clarithromycin 500 mg, and amoxicillin 1,000 mg, all twice daily for 7 days. Eradication was assessed by rapid urease test and histology 12 wk after surgery.RESULTS:By intention-to-treat (ITT) analysis, H. pylori eradication rates were 84.6% (95% CI 73.5–92.4) in the preop group and 83.1% (95% CI 71.7–91.2) in the postop group (P = 0.99). By per protocol (PP) analysis, the rates were 87.3% (95% CI 76.5–94.4) in the preop group and 86.9% (95% CI 75.8–94.2) in the postop group (P = 0.99). In the postop group, eradication rates did not differ with reconstruction method (Billroth I vs II, 80.4% [95% CI 66.1–90.6] vs 89.5% [95% CI 66.9–98.7] by ITT analysis (P = 0.49), and 85.7% [95% CI 71.5–94.6] vs 89.5% (95% CI 66.9–98.7) by PP analysis, P = 0.99).CONCLUSIONS:In distal gastric cancer patients, the effect of proton pump inhibitor-based triple therapy for H. pylori eradication was not different whether given postoperatively or preoperatively.