Forecasting age-standardized incidence rates of gastric cancer from 1990-2050 in Japan according to H. pylori prevalence and eradication scenarios.

Background: This study examines the influence of H. pylori eradication policies on gastric cancer incidence rates in Japan utilizing nationally representative registry data. It evaluates the impact of the H. pylori eradication policies introduced in 2000 and 2013, along with future eradication scenarios, on age-standardized gastric cancer rates.

Methods: Data from prefectural cancer registries and national health surveys were analyzed using Poisson regression and autoregressive integrated moving average models. Predictors such as H. pylori prevalence, alcohol consumption, salt intake, body mass index, and smoking prevalence were included. The study assessed past policies by comparing incidence rates with and without the policy changes of 2000 and 2013. Future policies were evaluated through five scenarios, incorporating the cumulative impact of eradication efforts from 2000 and 2013, and a projected 75% reduction by 2050. The evaluation also compared eradication targets for age groups 40-69 and 20-39.

Results: Past H. pylori eradication policies were associated with decreased age-standardized gastric cancer incidence rates in Japan, reducing the rate from a projected 39.3 per 100,000 without the 2000 and 2013 policies to 24.9 per 100,000 under current policies. Future policies, integrating the cumulative effects of the 2000 and 2013 eradication efforts and projecting a 75% reduction in H. pylori prevalence, were projected to further reduce gastric cancer incidence.

Conclusion: The H. pylori eradication policies of 2000 and 2013 have significantly reduced gastric cancer incidence rates in Japan. Model projections suggest that expanded eradication efforts could lead to additional reductions, further lowering the future burden of gastric cancer in Japan.