Background: There are conflicting data as to the role of Helicobacter pylori in the development of esophageal squamous cell carcinoma. We aimed to conduct a systematic review and quantitative meta-analysis to determine the relationship between H. pylori infection and squamous cell carcinoma of the esophagus.
Methods: Four electronic databases (Medline, PubMed, Embase, and Current Contents) were searched to 2014, with no language restrictions for observational studies. Additional manual searches were made of reference lists of relevant articles. From 3428 citations identified in this search, a total of 40 studies were identified meeting our inclusion criteria. Pooled odds ratios and 95% confidence intervals were calculated using a random effects model.
Results: The overall observation included 3806 cases and 15897 controls from 40 studies, of which 1749 cases and 5824 controls were H. pylori positive. Overall there was no statistically significant protective effect of H. pylori infection on esophageal squamous cell carcinoma (OR=0.82; 95% CI: 0.63-1.06). There was no evidence of publication bias (p=0.53)., but there was significant heterogeneity (I2=74%). Those with H. pylori cagA positive strains were associated with an increased risk of developing esophageal squamous cell carcinoma (OR=1.39; 95% CI: 1.14-1.71). There was no heterogeneity among these studies (I2=0%). This finding was further enforced by the strong relationship demonstrated in developing countries (OR=1.7; 95% CI: 1.25-2.32).
Conclusions: We have shown an association between H. pylori cagA positivity and esophageal squamous cell carcinoma.