title: Cholecystectomy as a risk factor for oesophageal adenocarcinoma.
abstract: BACKGROUND
  Owing to an increased risk of oesophageal bile exposure after cholecystectomy, an association with oesophageal adenocarcinoma is possible. There are some data in support of this hypothesis, and the aim of this study was to ascertain whether the association could be confirmed.
  
  
  METHODS
  A population-based cohort study was undertaken to compare the number of cases of oesophageal adenocarcinoma observed in a cohort of patients who have had a cholecystectomy in Sweden during 1965-2008 with the expected number, calculated from the entire Swedish population of corresponding age, sex and year. The risk of oesophageal adenocarcinoma was assessed by calculating the standardized incidence ratio (SIR) with 95 per cent confidence intervals.
  
  
  RESULTS
  The cholecystectomy cohort included 345 251 patients who were followed up for a mean of 15 years and contributed 4 854 969 person-years at risk. The total of 126 new cases of oesophageal adenocarcinoma was greater than expected (SIR 1.29, 1.07 to 1.53). The strength of the association between cholecystectomy and oesophageal adenocarcinoma tended to increase with longer follow-up after cholecystectomy. There was no association between cholecystectomy and oesophageal squamous cell carcinoma (SIR 0.93, 0.81 to 1.08), and in an unoperated cohort of 192 960 patients with gallstones no increased risk of oesophageal adenocarcinoma was identified (SIR 0.99, 0.71 to 1.35).
  
  
  CONCLUSIONS
  Cholecystectomy appears to be linked to an increased risk of oesophageal adenocarcinoma, but the absolute risk is small.
authors: Upper Gastrointestinal Research, Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden. jesper.lagergren@ki.se
authors: J
authors: J
authors: Lagergren
authors: F
authors: F
authors: Mattsson