title: Helicobacter pylori infection and the development of gastric cancer.
abstract: BACKGROUND
  Although many studies have found an association between Helicobacter 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 ulcers, gastric ulcers, gastric hyperplasia, or nonulcer dyspepsia at the time of enrollment; 1246 had H. pylori infection and 280 did not. The mean follow-up was 7.8 years (range, 1.0 to 10.6). Patients underwent endoscopy with biopsy at enrollment and then between one and three years after enrollment. H. pylori infection was assessed by histologic examination, serologic testing, 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 diffuse-type cancers. Among the patients with H. pylori infection, those with severe gastric atrophy, corpus-predominant gastritis, and intestinal metaplasia were at significantly higher risk for gastric cancer. We detected gastric 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 gastric atrophy, corpus-predominant gastritis, or intestinal metaplasia are at increased risk. Persons with H. pylori infection and nonulcer dyspepsia, gastric ulcers, or gastric hyperplastic polyps are also at risk, but those with duodenal ulcers are not.
authors.affiliation: Department of Gastroenterology, Kure Kyosai Hospital, Kure City, Japan. n-uemura@mua.biglobe.ne.jp
authors.forename: N
authors.initials: N
authors.lastname: Uemura
authors.forename: S
authors.initials: S
authors.lastname: Okamoto
authors.forename: S
authors.initials: S
authors.lastname: Yamamoto
authors.forename: N
authors.initials: N
authors.lastname: Matsumura
authors.forename: S
authors.initials: S
authors.lastname: Yamaguchi
authors.forename: M
authors.initials: M
authors.lastname: Yamakido
authors.forename: K
authors.initials: K
authors.lastname: Taniyama
authors.forename: N
authors.initials: N
authors.lastname: Sasaki
authors.forename: R J
authors.initials: RJ
authors.lastname: Schlemper
mesh_terms: D000328:Adult; D000368:Aged; D018572:Disease-Free Survival; D004381:Duodenal Ulcer / Q000150:complications; D004415:Dyspepsia / Q000150:complications; D005260:Female; D005756:Gastritis / Q000150:complications; D016481:Helicobacter Infections / Q000150:complications* / Q000175:diagnosis; D016480:Helicobacter pylori; D006801:Humans; D006965:Hyperplasia / Q000150:complications; D008297:Male; D008875:Middle Aged; D011127:Polyps / Q000150:complications; D011446:Prospective Studies; D013270:Stomach / Q000473:pathology; D013274:Stomach Neoplasms / Q000209:etiology*; D013276:Stomach Ulcer / Q000150:complications