Incidence of and risk factors for metachronous gastric cancer after endoscopic resection and successful Helicobacter pylori eradication: results of a large-scale, multicenter cohort study in Japan

Background A previous multicenter prospective randomized study from Japan showed that Helicobacter pylori eradication reduced the development of metachronous gastric cancer (MGC) after endoscopic resection for early gastric cancer. MGC risk, however, is not eliminated; yet few studies have evaluated its long-term incidence and risk factors. In this study, we investigated the incidence of and risk factors for MGC in patients who underwent endoscopic resection for early gastric cancer with successful H. pylori eradication. Methods A total of 594 patients who underwent endoscopic resection for early gastric cancer and successful H. pylori eradication at three institutions (National Cancer Center Hospital, University of Tokyo Hospital, and Wakayama Medical University Hospital) were analyzed retrospectively. Annual endoscopic surveillance was performed after initial endoscopic resection. MGC was defined as a gastric cancer newly detected at least 1 year after successful H. pylori eradication. Results Ninety-four MGCs were detected in 79 patients during the 4.5-year median follow-up period. Kaplan–Meier analysis showed the cumulative incidence of MGC 5 years after successful H. pylori eradication was 15.0 %; the incidence of MGC calculated by use of the person-year method was 29.9 cases per 1000 person-years. Multivariate analysis using the Cox proportional hazards model revealed that male sex, severe gastric mucosal atrophy, and multiple gastric cancers before successful H. pylori eradication were independent risk factors for MGC. Eleven percent of MGCs (10 of 94) were detected more than 5 years after successful H. pylori eradication. Conclusion Surveillance endoscopy for MGC in patients who have undergone endoscopic resection for early gastric cancer should be performed even after successful H. pylori eradication.