Opportunistic Gastric Cancer Endoscopic Screening Integrated Into Population‐Based Colorectal Cancer Screening: A Retrospective Economic Cost‐Comparison Study

BACKGROUND: Gastric cancer (GC) remains a major cause of cancer-related mortality worldwide, with prognosis and treatment costs strongly influenced by disease stage at diagnosis. Endoscopic GC screening has been proposed for intermediate-to-high-risk countries, although its economic feasibility remains uncertain. This study evaluated the costs associated with opportunistic GC screening integrated into a colorectal cancer screening programme and compared modeled early-stage management scenarios with the real-world costs of managing Stages II-IV disease. METHODS: A retrospective cost-comparison study was conducted from the perspective of the Portuguese National Health Service. Screening costs were derived from 377 fecal immunochemical testing-positive individuals undergoing one-time opportunistic esophagogastroduodenoscopy (EGD) during colonoscopy within the organized colorectal cancer screening programme, and treatment costs from a retrospective cohort of 222 patients with gastric adenocarcinoma. Direct medical costs were analyzed according to disease stage and compared with two modeled early-stage management scenarios. RESULTS: Gastric precancerous conditions were identified in 46.9% of screened individuals, and gastric adenocarcinoma was detected in 0.8% (3/377). The estimated screening cost was €17,249 per cancer detected. Mean treatment and follow-up costs per patient were €32,140 for Stage II disease, €33,073 for Stage III disease, and €19,287 for Stage IV disease. The estimated cumulative cost of screening followed by ESD was €27,624, whereas screening followed by surgical treatment of Stage I disease was estimated at €44,493. CONCLUSIONS: GC management is associated with substantial healthcare expenditure. The potential economic value of opportunistic GC screening is likely to depend on the detection of lesions amenable to endoscopic treatment. TRAIL REGISTRATION: NCT07522320.