11 The Rising Incidence of Esophageal Adenocarcinoma is Not Accompanied With an Increase in Mortality: Results of a Population-Based Cohort Study

Abstract

Background:It has been proved thatH. pylori eradication prevents the incidence of metachronous gastric cancer after endoscopic resection (ER) of primary early gastric cancer during short-term follow-up. However, it has not been clarified whether preventive effect of H. pylori eradication for gastric cancer continues in the long term. To determine the long-term effect of H. pylori eradication on the development of gastric cancer, a follow-up study of a JGSG trial (Lancet 2008; 372: 392-7) was conducted. Methods: In this multi-center, openlabel, randomized controlled trial, 544 patients who received ER of early gastric cancer were randomly assigned to the H pylori eradication group (n=272) or to the control group (n= 272). Endoscopy was performed every year after randomization to evaluate metachronous cancer. Diagnosis of a new gastric cancer at another site of the stomach was defined as primary endpoint. Metachronous cancers were confirmed through histological examination. The frequency of metachronous cancer in the eradication group was compared to that in the control group. Results: There were no significant differences between eradication and control groups in baseline characteristics. The follow-up period was 10 years at maximum. After three years of follow-up, metachronous gastric cancer was detected in 32 participants. In the end, metachronous gastric carcinoma had developed in 22 patients in the eradication group and 43 in the control group. In the modified intention-to-treat population, including patients with at least one post-randomization assessment of tumor status and adjusting for loss to follow-up (255 patients in the eradication group, 250 in the control group), the hazard ratio for metachronous gastric carcinoma was 0.497 (95% CI 0.2970.831; p=0.008). The eradication group and the control group showed no difference in characteristics of metachronous cancer. Conclusions: This study showed that H. pylori eradication prevented the development of metachronous gastric cancers after ER during long-term follow-up.