title: Helicobacter species are associated with possible increase in risk of hepatobiliary tract cancers.
abstract: BACKGROUND
  Attempts at early identification of hepatobiliary cancers have failed due to non-availability of a sensitive test. Prevention offers the best chance to reduce the morbidity and mortality from these. Identification of an etiological agent and especially if the potentially identified cause can be eradicated like Helicobacter sp. infection, will not only reduce incidence but also the mortality.
  
  
  METHODS
  This article reviews 15 studies on Helicobacter species in hepatobiliary cancers identified on pubmed, scopus and google scholar search. Of these, Five were single group and 10 were case control. These 10 case control studies were included in the meta analysis, which was carried out using odds ratio and both a fixed and random effect model, 95% confidence intervals for odds ratio was calculated. Chi square test for heterogeneity was employed. The overall effect was calculated using Z test.
  
  
  RESULTS
  The cumulative sample size of cases was 205, of which 115 were positive (56%) for Helicobacter, while among 263 controls 53 (20%) were found to be positive for Helicobacter infection. The positivity rate in case control studies was higher than that observed in single group studies. The cumulative odds ratio for the study sample was 8.72 (95% CI 4.78-15.91) (Z=7.07; p<0.00001).
  
  
  CONCLUSIONS
  There is enough evidence to suggest a possible role of Helicobacter species in hepatobiliary tract cancers. However, the results from different regions of the world differ. Studies also differ on method of Helicobacter detection, subsite of cancer with in the hepatobiliary tract and choice of controls thus introducing heterogeneity. Further case control studies with larger sample size are required to settle the question.
authors: Department of Surgical Oncology, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221 005, India. manojpandey@vsnl.com
authors: Manoj
authors: M
authors: Pandey
authors: Mridula
authors: M
authors: Shukla
mesh_terms: D001661:Biliary Tract Neoplasms / Q000453:epidemiology / Q000209:etiology*; D016481:Helicobacter Infections / Q000150:complications* / Q000453:epidemiology; D016480:Helicobacter pylori; D006801:Humans; D008113:Liver Neoplasms / Q000453:epidemiology / Q000209:etiology*