Helicobacter pylori infection and the development of gastric cancer.

Background: Although many studies have found an association between Helicob acter pylori infection and the development of gastric cancer, many aspects of this relation remain uncertain. Methods: We prospectively studied 1526 Japanese patients who had duodenal u lcers, gastric ulcers, gastric hyperplasia, or nonulcer dyspepsia at the ti me of enrollment; 1246 had H. pylori infection and 280 did not. The mean fo llow-up was 7.8 years (range, 1.0 to 10.6). Patients underwent endoscopy wi th biopsy at enrollment and then between one and three years after enrollme nt. H. pylori infection was assessed by histologic examination, serologic t esting, and rapid urease tests and was defined by a positive result on any of these tests. Results: Gastric cancers developed in 36 (2.9 percent) of the infected and none of the uninfected patients. There were 23 intestinal-type and 13 diffu se-type cancers. Among the patients with H. pylori infection, those with se vere gastric atrophy, corpus-predominant gastritis, and intestinal metaplas ia were at significantly higher risk for gastric cancer. We detected gastri c cancers in 21 (4.7 percent) of the 445 patients with nonulcer dyspepsia, 10 (3.4 percent) of the 297 with gastric ulcers, 5 (2.2 percent) of the 229 with gastric hyperplastic polyps, and none of the 275 with duodenal ulcers . Conclusions: Gastric cancer develops in persons infected with H. pylori but not in uninfected persons. Those with histologic findings of severe gastri c atrophy, corpus-predominant gastritis, or intestinal metaplasia are at in creased risk. Persons with H. pylori infection and nonulcer dyspepsia, gast ric ulcers, or gastric hyperplastic polyps are also at risk, but those with duodenal ulcers are not. (N Engl J Med 2001;345:784-9.) Copyright (C) 2001 Massachusetts Medical Society.