Population-Based Gastric Cancer Screening in Japan: Evolution, Challenges, and Lessons for Implementation.

Japan has developed one of the world's most established population-based gastric cancer screening systems through more than six decades of continuous refinement in public health policy, technological innovation, and quality assurance. This review summarizes the historical development, technological evolution, quality assurance framework, and future perspectives of gastric cancer screening in Japan, while providing comparisons with major gastric cancer screening programs and prevention initiatives worldwide. Japanese gastric cancer screening can be traced to the postwar adaptation of mass tuberculosis radiographic screening systems, followed by the nationwide implementation of double-contrast upper gastrointestinal radiography. Subsequent advances in gastrointestinal endoscopy, including high-resolution imaging, magnifying endoscopy, and image-enhanced endoscopy, have facilitated the transition toward endoscopic screening and improved early gastric cancer detection. Japan has also established highly standardized quality assurance systems, including structured training, credentialing, standardized examination protocols, defined quality indicators, and continuous program monitoring of screening performance. These efforts have supported the standardization and continuous quality improvement of population-based gastric cancer screening programs. The incidence and risk-factor profile of gastric cancer are changing rapidly because of declining Helicobacter pylori prevalence, population aging, and increasing recognition of Helicobacter pylori-naïve gastric cancer. Consequently, future screening systems will likely require greater incorporation of personalized risk stratification, optimized allocation of endoscopic resources, and emerging technologies such as artificial intelligence-assisted endoscopy and structured digital quality assurance systems. Japan's experience provides a valuable case study illustrating how quality assurance, technological innovation, and public health infrastructure can be integrated to support population-based gastric cancer screening.