Cost-effectiveness of RIMS1 methylation-guided gastric cancer surveillance after Helicobacter pylori eradication

BACKGROUND: The cost-effectiveness of methylation-guided surveillance after Helicobacter pylori eradication remains uncertain. RESEARCH DESIGN AND METHODS: From a healthcare system perspective, a cohort model compared annual, biennial, and RIMS1 methylation-guided surveillance over 30 years in Japanese patients aged 50 years with open-type gastric atrophy. Differences in stage at diagnosis were calibrated from annual-surveillance data. Costs and quality-adjusted life-years (QALYs) were discounted at 3.0% annually. Sensitivity analyses examined uncertainty; an exploratory analysis used Korean inputs. RESULTS: At US$52,037.74/QALY, methylation-guided surveillance had the highest net monetary benefit (NMB). Compared with biennial surveillance, its incremental cost-effectiveness ratio was US$47,021.24/QALY and incremental NMB was US$62.56/person. It reduced routine endoscopies by 40.9% versus annual surveillance. Cost-effectiveness varied with surveillance duration, endoscopy-related utility loss, implementation costs, and risk misclassification. Across 5,000 probabilistic draws, methylation-guided surveillance had the highest mean NMB, but biennial surveillance was more often optimal (51.2% vs 36.0%). The preferred strategy in the Korean analysis varied with endoscopy costs. CONCLUSIONS: In the base-case analysis, RIMS1-guided surveillance was cost-effective, increasing QALYs compared with biennial surveillance and reducing endoscopy use compared with annual surveillance. Its estimated cost-effectiveness depends on the assumed improvement in stage at diagnosis with more frequent surveillance.