H. pylori decline associated with increased risk for esophageal adenocarcinoma

Results from a meta-analysis suggested an inverse association between CagA–positive Helicobacter pylori colonization and the risk for esophageal adenocarcinoma.

The prominent decline of H. pylori colonization may be partly responsible for the recent increased incidence of esophageal adenocarcinomas in Western countries, according to researchers from the NCI.

H. pylori has coexisted with modern humans and could previously be found in the stomachs of most humans. With advances in sanitation and use of antibiotics, however, this bacterium is rapidly disappearing from human populations, especially in Western countries. H. pylori has been linked to benign and malignant gastrointestinal tract diseases.

The researchers conducted a meta-analysis to examine the association between H. pylori and esophageal adenocarcinoma and esophageal squamous cell carcinoma. They searched the PubMed database, the ISI database and the references of the selected articles to select case-control or nested case-control studies that employed serology or endoscopic methods to detect H. pylori in the stomach. Nineteen studies were included in the meta-analysis.

For esophageal adenocarcinoma, the summary OR was 0.56 (95% CI, 0.46-0.68). Further analysis showed that colonization with CagA–positive strains was inversely associated with the risk for esophageal adenocarcinoma (OR=0.41; 95% CI, 0.28-0.62); negative strains did not have an inverse association (OR=1.08; 95% CI, 0.76-1.53). For esophageal squamous cell carcinoma, the summary OR was 1.10 (95% CI, 0.78-1.55).

This evidence suggested that colonization of the stomach with CagA–positive strains of H. pylori may protect against esophageal adenocarcinoma. For esophageal adenocarcinoma, there was little evidence of heterogeneity, and the results were robust to multiple subgroup analyses, according to the researchers.

Cancer Prev Res. 2008;1:329-338.