Risk of gastric cancer in the second decade of follow-up after Helicobacter pylori eradication

Background and aimsEradication of Helicobacter pylori reduces the risk of gastric cancer. In this study, we investigated the risk beyond 10 years after eradication of H. pylori.MethodsWe conducted a retrospective cohort study of 2737 patients who had yearly endoscopic follow-up after cure of H. pylori infection. For comparison of gastric cancer risk in the second decade of follow-up with that in the first decade, we calculated standardized incidence ratios (SIRs) by dividing the number of observed cases of gastric cancer in the second decade of follow-up by that of expected cases which was estimated using the incidence rate ratio of age in the first decade.ResultsDuring the follow-up for as long as 21.4 years (mean 7.1 years), gastric cancer developed in 68 patients (0.35% per year). The SIRs for diffuse-type gastric cancer was infinity (0 expected case and 4 observed cases) in patients with mild gastric mucosal atrophy and 10.9 (95% confidence interval 4.53-26.1) with moderate atrophy, whereas no significant increase of SIRs was observed in intestinal-type cancer regardless of the grade of baseline gastric atrophy or in diffuse-type cancer in patients with severe atrophy even though who had the highest risk.ConclusionsThe longer the follow-up, the greater the risk of developing diffuse-type gastric cancer becomes in patients with mild-to-moderate gastric atrophy at baseline. Endoscopic surveillance should be continued beyond 10 years after cure of H. pylori irrespective of the severity of gastric atrophy.