Helicobacter bilis in Human Gallbladder Cancer: Results of aCase-control Study and a Meta-analysis

Introduction: Gallbladder cancer is an uncommon neoplasm of uncertain etiology and poor survival.Recently, interest has been generated in bacterial infections and cancers. Helicobacter is one such bacteriumfound to be associated with gastric MALToma, gastric adenocarcinoma and hepatobiliary neoplasms. Patientsand methods: Fifty four gallbladder cancer and 55 controls with cholelithiasis were studied. Helicobacter biliswas identified using 16S rRNA PCR. Relative risk and odds ratio with 95% CI were estimated. A detailed searchof literature was carried out and selected relevant articles were extracted. A meta analysis was carried outusing a random effect model.
Results: Helicobacter bilis was identified in 32/54 patients and 32/55 controls, Therelative risk of gallbladder cancer in H. bilis positive cases was 1.05 (95% CI 0.49 to 2.24). Of the 10 identifiedcase control studies on Helicobacter in the hepatobiliary tract 3 each were on gallbladder cancer and H. bilis. Inmeta analysis a pooled odds ratio of 4.13 (95% CI 2.68-6.36) favoring Helicobacter was observed. Pooled analysisof published studies on gallbladder cancer showed an odds ratio of 1.24 (95% CI 0.63-2.44).
Conclusions: Thepresent study failed to demonstrate any increase in risk of gallbladder cancer in presence of Helicobacter bilis.It may be hypothesized that increased risk observed in earlier studies may be indirectly due to increase in therisk of gallstones, although lack of any study specifically looking at this aspect and absence of normal controlsin the present study makes this assumption superfluous.