Impact of the timing of Helicobacter pylori eradication on the risk of development of metachronous lesions after treatment of early gastric cancer: a population-based cohort study.

BACKGROUND AND AIMS: Helicobacter pylori eradication can reduce the risk of metachronous lesions after the treatment of early gastric cancer. We aimed to analyze the impact of the timing of H pylori eradication on metachronous recurrence. METHODS: Data of patients who underwent endoscopic resection or partial gastrectomy for early stage gastric cancer and received H pylori eradication therapy were obtained from the Korean National Health Insurance Service database. Patients were classified into 3 groups according to the timing of the prescription for H pylori eradication: preresection; within 1 year postresection; and >1 year postresection. RESULTS: Among 19,767 patients, 7452 and 12,315 underwent endoscopic resection and surgery, respectively. The 5-year cumulative incidence of metachronous lesions after endoscopic resection was 14.0% in the preresection group, 12.3% in the within 1 year postresection group, and 16.9% in the >1 year postresection group. Surgery was performed in 1.2% of the preresection group, 1.3% of the within 1 year postresection group, and 2.9% of the >1 year postresection group. The within 1 year postresection group had a lower risk of development of metachronous lesions than the >1 year postresection group (hazard ratio [95% confidence interval]: after endoscopic resection, 0.79 [0.65-0.95]; after surgery, 0.39 [0.28-0.53]). The risk of development of metachronous lesions did not differ between the preresection and within 1 year postresection groups. CONCLUSION: Prescription of H pylori eradication therapy within 1 year after gastric cancer treatment reduces the risk of development of metachronous gastric neoplasms compared with a late prescription of eradication therapy in patients undergoing endoscopic resection and those undergoing surgery.