Planning the De-escalation of Population-Based Gastric Cancer Screening in Japan in the Post-Helicobacter pylori Era

Japan developed population-based gastric cancer screening in response to a large gastric cancer burden. Historically, the screening-eligible population had widespread exposure to Helicobacter pylori (H. pylori), a major cause of gastric cancer. The current national model identifies adults aged 50 years or older as the principal screening-eligible population and recommends biennial radiographic or endoscopic screening. This epidemiologic premise is changing as H. pylori-naïve birth cohorts enter screening-eligible ages, shifting the baseline risk profile underlying uniform age-based screening. H. pylori infection and H. pylori-related mucosal changes, including atrophic gastritis and intestinal metaplasia, are central determinants of gastric cancer risk in Japan. A systematic review and meta-regression estimated H. pylori-naïve prevalence at 21.1% for the 1930 birth cohort, 75.3% for 1970, and 97.7% for 2010, with a plateau above 95% after 2000. A meta-analysis of 248,482 H. pylori-naïve adults identified 96 gastric cancer cases. The pooled screen-detected prevalence was 0.029%, corresponding to approximately one case per 3,500 screened individuals; the pooled incidence was 1.40 per 10,000 person-years. Combined with future population projections, the H. pylori-naïve proportion among adults aged 50 years or older is projected to increase from 57.6% in 2026 to 85.8% in 2056. These projections indicate that uniform screening will increasingly include adults with low baseline gastric cancer risk. Japan is therefore approaching the point at which uniform biennial screening for all adults aged 50 years or older will require reassessment. The current screening program may largely continue through the 2030s, but later starting ages and longer screening intervals should be evaluated during the 2040s. By the 2050s, routine population-based screening for average-risk adults may need to be phased out within a planned de-escalation strategy, while individuals with established high-risk conditions continue to receive appropriate clinical follow-up or surveillance.