title: Meta-analysis: oral bisphosphonates and the risk of oesophageal cancer.
abstract: BACKGROUND
  Bisphoshonates, which are used in the treatment and prevention of osteoporosis, have recently been implicated in the development of oesophageal cancer; however, studies report conflicting data.
  
  
  OBJECTIVE
  To conduct a meta-analysis of studies reporting on the association between bisphosphonates and oesophageal cancer to quantify the relationship.
  
  
  METHODS
  A search was conducted through Medline, PubMed, Embase and Current Contents Connect to 2 August 2012. We calculated pooled odds ratios and 95% CIs using a random effects model for the risk of oesophageal cancer associated with exposure to bisphosphonates, as well as for the different periods of exposure.
  
  
  RESULTS
  Seven studies, with 19 700 oesophageal cancer cases, met our inclusion criteria. We found a positive relationship between exposure to bisphosphonates and oesophageal cancer, with an odds ratio (OR) of 1.74 with a 95% CI of 1.19-2.55. Heterogeneity was observed (I(2 ) = 85%, P < 0.001). Publication bias was not present. An increased risk of oesophageal cancer was also found in the group exposed to bisphosphonates for a longer period of time, compared with the group who experienced a shorter period of exposure (OR 2.32; 95% CI 1.57-3.43 vs. OR 1.35; 95% CI 0.77-2.39). An increased risk was associated with exposure to Etidronate (OR 1.58; 95% CI 1.12-2.24), but not to Aledronate.
  
  
  CONCLUSIONS
  Exposure to bisphosphonates may be associated with an increased risk of oesophageal cancer. More studies are needed to confirm the relationship.
authors.affiliation: The Whiteley-Martin Research Centre, Discipline of Surgery, The University of Sydney, Sydney Medical School, Nepean, Penrith, NSW, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Andrici
authors.forename: M
authors.initials: M
authors.lastname: Tio
authors.forename: G D
authors.initials: GD
authors.lastname: Eslick
mesh_terms: D000284:Administration, Oral; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000009:adverse effects*; D004164:Diphosphonates / Q000008:administration & dosage / Q000009:adverse effects*; D004938:Esophageal Neoplasms / Q000139:chemically induced*; D006801:Humans; D008962:Models, Theoretical; D016017:Odds Ratio; D016032:Randomized Controlled Trials as Topic; D012306:Risk
chemical_list: D050071:Bone Density Conservation Agents; D004164:Diphosphonates