METAANALYSIS OF THE RELATIONSHIP BETWEEN HELICOBACTER-PYLORI SEROPOSITIVITY AND GASTRIC-CANCER

Background di Aims: Reports in the literature regarding the relationsh ip of Helicobacter pylori infection to gastric cancer are conflicting. The aim of this study was to identify the source of heterogeneity bet ween studies. Methods: Meta-analysis of cohort or case-control studies with age- and/or sex-matched controls, providing raw data on H. pylor i infection detected by serology, was used. Results: A fully recursive literature search identified 19 qualified studies with 2491 patients and 3959 controls. Test for homogeneity found a significant difference in odds ratio between patients with early and advanced gastric cancer (6.35 vs. 2.13; P = 0.01), patients with cardiac and noncardiac gastr ic cancer (1.23 vs. 3.08; P = 0.003), and population and hospital-base d controls (2.11 vs. 1.49; P < 0.001). The summary odds ratio for gast ric cancer in H. pylori-infected patients is 1.92 (95% confidence inte rval [CI], 1.32-2.78), 2.24 (95% CI, 1.15-4.4), and 1.81 (95% CI, 1.16 -2.84) for all studies, cohort, and case-control studies, respectively . H. pylori-infected younger patients have a higher relative risk for gastric cancer than older patients with odds ratios decreasing from 9. 29 at age less than or equal to 29 years to 1.05 at age greater than o r equal to 70 years. H. pylori infection is equally associated with th e intestinal or diffuse type of gastric cancer. Conclusions: H. pylori infection is a risk factor for gastric cancer. The heterogeneity of r eported results is caused by differences in the selection of controls, patient age, and the site and stage of gastric cancer.