[H. pylori infection and the development of gastric cancer in Japan].

In Japan, where the incidence of gastric cancer is the highest in the world due to its different health care insurance system from Europe and the US, early-stage gastric cancer is more often discovered by endoscopy. This paper describe the relationship between H. pylori infection and development of gastric cancer in Japan. Our study shows that, during the 8 year follow-up, gastric cancer developed in 36 of the 1,246 H. pylori-infected patients(2.9%), but in none of the 280 uninfected patients. In terms of the development status of gastric cancer over time, our study estimated the risk of gastric cancer in H. pylori-positive patients to be about 5% at ten years. Epidemiologically, just as cancer of the liver is closely associated with hepatitis C viral infection, a majority of gastric cancers are known to develop from the persistent inflammation of the gastric mucosa caused by H. pylori infection. It is therefore considered rare for clinical gastric cancer to develop in uninfected patients--rigorously diagnosed after taking into account the possibility of false negative results occurring in various test methods--or, in other words, in gastric mucosa having no persistent inflammation.