Helicobacter pylori Treatment and Gastric Cancer Risk After Endoscopic Resection of Dysplasia: A Nationwide Cohort Study.

BACKGROUND & AIMS: The study investigated the association between Helicobacter pylori treatment and the risk of gastric cancer after endoscopic resection of gastric dysplasia. METHODS: Patients who received endoscopic resection for gastric dysplasia between 2010 and 2020 from Korean nationwide insurance data were included. We verified the occurrence of new-onset gastric cancer and metachronous gastric neoplasm, which encompasses both cancer and dysplasia, >1 year after the index endoscopic resection. Newly diagnosed gastric cancer ≥3 years and ≥5 years was regarded as late-onset gastric cancer. A multivariable Cox regression model with H pylori treatment status as a time-dependent covariate was used to determine the risk of gastric cancer and metachronous gastric neoplasms. RESULTS: Gastric dysplasia in 69,722 patients was treated with endoscopy, and 49.5% were administered H pylori therapy. During the median 5.6 years of follow-up, gastric cancer developed in 2406 patients and metachronous gastric neoplasms developed in 3342 patients. Receiving H pylori therapy was closely related to lower gastric cancer risk (adjusted hazard ratio [aHR], 0.88; 95% confidence interval [CI], 0.80-0.96). H pylori treatment also significantly decreased metachronous gastric neoplasm development (aHR, 0.76; 95% CI, 0.70-0.82). Furthermore, H pylori therapy showed a prominent protective effect for late-onset gastric cancer development at ≥3 years (aHR, 0.84; 95% CI, 0.75-0.94) and ≥5 years (aHR, 0.80; 95% CI, 0.68-0.95). CONCLUSIONS: In this nationwide cohort, H pylori therapy after endoscopic resection of gastric dysplasia was associated with a reduced risk of gastric cancer and metachronous gastric neoplasm occurrence.