ENDOSCOPIC GASTRIC CANCER SCREENING IN JAPAN: THE PRESENT AND FUTURE

Abstract

The evidences, problems and future of endoscopic gastric cancer screening in Japan are discussed. Endoscopic gastric cancer screening has reduced gastric cancer deaths to 23-71% of the number of gastric cancer deaths prior to the introduction of endoscopic gastric cancer screening. The effect of endoscopic gastric cancer screening in reducing gastric cancer deaths is greater than that of upper gastrointestinal X-ray screening with barium sulphate (UGIS). The feasibility of endoscopic gastric cancer screening depends on the capacity of endoscopic examination, budget for screening and access to facilities where individuals undergo endoscopic examination. If endoscopic gastric cancer screening is not feasible, secondary endoscopic examination after UGIS in which the background gastric mucosa is evaluated for chronic gastritis, is more efficient than primary endoscopic screening. Merits and demerits of endoscopic screening should be considered before introducing endoscopic gastric cancer screening because endoscopic examination is associated with severe adverse events. The Japan Ministry of Health, Labour and Welfare aims at a gastric cancer screening rate of 40% or greater. However, the prevalence of Helicobacter pylori infection is decreasing, and the adjusted number of gastric cancer deaths has been decreasing in Japan. Therefore, a simple policy that encourages an increase in the screening rate is not always efficient irrespective of increasing the budget and workload of medical staffs. A primary endoscopic screening system may be needed to stratify subjects with gastric cancer risks such as H. pylori infection and atrophy. Not only risk stratification but also endoscopic screening by special technologists or nurses who are assisted by artificial intelligence (AI) may decrease the workloads of endoscopists. It is expected that intervention with such gastric cancer screenings may reduce gastric cancer deaths more efficiently than the natural decrease in gastric cancer deaths in the future.