THE RISK OF STOMACH-CANCER IN PATIENTS WITH GASTRIC OR DUODENAL-ULCERDISEASE

Background Helicobacter pylori infection, now considered to be a cause of gastric cancer, is also strongly associated with gastric and duode nal ulcer disease. The discovery of these relations has brought the lo ng-controversial connection between peptic ulcers and gastric cancer i nto focus. Methods We estimated the risk of stomach cancer in a large cohort of hospitalized patients with gastric or duodenal ulcers, as re corded in the Swedish Inpatient Register between 1965 and 1983. Altoge ther, 57,936 patients were followed through 1989, for an average of 9. 1 years. The standardized incidence ratio - the ratio of the observed number of cancers to the number expected on the basis of the incidence in the Swedish population at large - was used as a measure of relativ e risk. Results After peaking in the first 3 years of followup, the st andardized incidence ratio for gastric cancer among 29,287 patients wi th gastric ulcers leveled off at 1.8 (95 percent confidence interval, 1.6 to 2.0) and remained significantly increased throughout followup, which was as long as 24 years for some patients. Prepyloric ulcer, dia gnosed in 8646 patients, was not associated with a significant excess risk (standardized incidence ratio, 1.2; 95 percent confidence interva l, 0.8 to 1.6). In the cohort of patients with duodenal ulcers (24,456 patients), the incidence of gastric cancer was significantly lower th an expected. After the second year of follow-up, the standardized inci dence ratio was only 0.6 (95 percent confidence interval, 0.4 to 0.7) and remained stable thereafter. Conclusions Gastric ulcer disease and gastric cancer have etiologic factors in common. A likely cause of bot h is atrophic gastritis induced by H. pylori. By contrast, there appea r to be factors associated with duodenal ulcer disease that protect ag ainst gastric cancer. (C) 1996, Massachusetts Medical Society.