<i>Helicobacter pylori</i> eradication treatment and the risk of gastric adenocarcinoma in a Western population.

Abstract

Gastric infection with <i>Helicobacter pylori</i> is a strong risk factor for non-cardia gastric adenocarcinoma. The aim of this study was to assess whether the risk of gastric adenocarcinoma and non-cardia gastric adenocarcinoma decreases after eradication treatment for <i>H. pylori</i> in a Western population. This was a nationwide, population-based cohort study in Sweden in 2005-2012. Data from the Swedish Prescribed Drug Registry provided information on <i>H. pylori</i> eradication treatment, whereas information concerning newly developed gastric adenocarcinoma was retrieved from the Swedish Cancer Registry. The risk of gastric adenocarcinoma and non-cardia gastric adenocarcinoma in individuals who had received <i>H. pylori</i> eradication treatment was compared with the background population of the corresponding age, sex and calendar year distribution, yielding standardised incidence ratios (SIRs) with 95% CIs. During the follow-up of 95 176 individuals who had received eradication treatment (351 018 person-years at risk), 75 (0.1%) developed gastric adenocarcinoma and 69 (0.1%) developed non-cardia gastric adenocarcinoma. The risk of gastric adenocarcinoma decreased over time after eradication treatment to levels below that of the corresponding background population. The SIRs were 8.65 (95% CI 6.37 to 11.46) for 1-3 years, 2.02 (95% CI 1.25 to 3.09) for 3-5 years and 0.31 (95% CI 0.11 to 0.67) for 5-7.5 years after eradication treatment. When restricted to non-cardia adenocarcinoma, the corresponding SIRs were 10.74 (95% CI 7.77 to 14.46), 2.67 (95% CI 1.63 to 4.13) and 0.43 (95% CI 0.16 to 0.93). Eradication treatment for <i>H. pylori</i> seems to counteract the development of gastric adenocarcinoma and non-cardia gastric adenocarcinoma in this Western population.