Sensitivity and specificity of endoscopic and radiographic screening for localized gastric cancer in a real-world, population-based setting.

BACKGROUND: In Japan, radiography with barium meal and endoscopy are recommended methods for population-based gastric cancer screening for individuals aged ≥ 50 years. However, no recent real-world evidence is available on the performance of endoscopic and radiographic screening in detecting localized gastric cancer. Therefore, we estimated the sensitivity and specificity of endoscopy and radiography in detecting gastric cancer and its clinical stages in a real-world, population-based screening setting. METHODS: We cross-referenced data from a population-based gastric cancer screening database with a regional cancer registry database. We calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value of endoscopy (n = 61,658) and radiography (n = 73,653) for gastric cancer and its clinical stages. Age- and sex-standardized sensitivity values were estimated using regression standardization. RESULTS: For localized gastric cancer, endoscopy showed higher sensitivity (83.4% vs. 65.3%), specificity (99.0% vs. 88.7%), and PPV (27.4% vs. 2.2%) than radiography. The corresponding estimates for men were 83.3% vs. 65.6%, 98.7% vs. 87.3%, and 31.1% vs. 3.1%; for women, they were 83.6% vs. 64.5%, 99.3% vs. 89.9%, and 20.5% vs. 1.2%. The age- and sex-standardized sensitivity of endoscopy was also higher than that of radiography (83.6% vs. 65.3%, p < 0.001). CONCLUSIONS: In this descriptive study, endoscopy showed higher sensitivity, specificity, and PPV than radiography for gastric cancer overall and across its clinical stages (localized, regional, distant). Our findings provide updated evidence to inform population-based screening efforts in countries with high gastric cancer incidence.