title: Cholecystectomy and the risk of esophageal and gastric cancer.
abstract: OBJECTIVE
  To conduct a meta-analysis of observational studies to explore the relationships between cholecystectomy and the risk of esophageal and gastric cancer (GC).
  
  
  METHODS
  The study design was retrospective, and carried out in the First People's Hospital of Nantong, Jiangsu, China from January 2012 to April 2012. Studies were identified by a literature search of MEDLINE and EMBASE through March 31, 2012, and by manually searching the reference lists of pertinent articles. The summary relative risks (SRRs) with their 95% confidence intervals (CIs) were calculated with a random-effects model.
  
  
  RESULTS
  A total of 12 estimates from 6 independent studies (including 1,622 esophageal cancer [EC] cases and 2,314 GC cases) were included in this meta-analysis. We found that cholecystectomy was not associated with risk of EC and GC (EC: SRRs--1.03; 95% CI: 0.94-1.13; heterogeneity: p=0.496; I2=0; n=4 studies; [GC: SRRs--1.03; 95% CI: 0.93-1.13; heterogeneity: p=0.652; I2=0; n=5 studies]). Sub-grouped analyses revealed that these null associations were independent of geographic location and study design. Based on 2 studies, we found patients undergoing cholecystectomy at least 10 years before had an elevated risk of esophageal adenocarcinoma (EAC).
  
  
  CONCLUSIONS
  The results of this meta-analysis suggest that cholecystectomy does not increase the risk of esophageal squamous cell carcinoma and GC development, but may increase EAC risk. More epidemiological research of a prospective design is needed to further clarify these associations in the future.
authors.affiliation: Department of Gastroenterology, the First People's Hospital of Nantong, Nantong, Jiangsu, China.
authors.forename: Zhenming
authors.initials: Z
authors.lastname: Ge
authors.forename: Chengjin
authors.initials: C
authors.lastname: Zhao
authors.forename: Yamin
authors.initials: Y
authors.lastname: Wang
authors.forename: Junbo
authors.initials: J
authors.lastname: Qian
mesh_terms: D016022:Case-Control Studies; D002763:Cholecystectomy / Q000009:adverse effects*; D015331:Cohort Studies; D004938:Esophageal Neoplasms / Q000209:etiology*; D006801:Humans; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000209:etiology*