H. pylori infection and the development of gastric cancer.

BACKGROUND: Recently, many study have shown that Helicobacter pylori infection is crucial in development of atrophic gastritis, which is closely associated with gastric cancer. We conducted a long-term endoscopic prospective follow-up study to investigate the development of gastric cancer in H. pylori-positive and -negative patients. METHODS: 1,603 patients who underwent endoscopy and were assessed as to the presence of H. pylori infection by histology, rapid urease test and serologic test between April 1990 and March 1993 were entered. We prospectively studied 1246 subjects with and 280 subjects without H. pylori infection for a mean follow-up of 7.8 years (range 1-10.6 years). RESULTS: Gastric cancer of both the intestinal and diffuse type developed in 36 (2.9%) infected patients but in none of the uninfected patients during follow-up. There was an increased risk for gastric cancer in infected patients with severe gastric atrophy and corpus predominant gastritis and intestinal metaplasia. Gastric cancer was detected in 21 (4.7%) of the patients with non ulcer dyspepsia, in 10 (3.4%) of those with gastric ulcer and in 5 (2.2%) of those with gastric hyperplastic polyp, at enrollment. No gastric cancer was detected in duodenal ulcer patients. CONCLUSION: These results suggest that the development of both types of gastric cancer is caused by H. pylori-associated gastritis, and the risk for development of gastric cancer in H. pylori-negative subjects is extremely low. Subjects having H. pylori-positive gastric mucosa with severe atrophy and/or corpus gastritis may be at particularly high risk for gastric cancer.