title: Risk of hepato-biliary cancer after cholecystectomy: a nationwide cohort study.
abstract: BACKGROUND
  Epidemiologic studies have identified cholecystectomy as a possible risk factor for cancers in Western countries. The aim of this study was to estimate the risk of hepato-biliary cancer after cholecystectomy in Taiwan.
  
  
  METHODS
  Based on the Taiwan National Health Insurance Research Database, 2,590 cholecystectomized patients without prior cancers in the period 1996-2008 were identified from a cohort dataset of 1,000,000 randomly sampled individuals. The standard incidence ratio (SIR) of each cancer was calculated.
  
  
  RESULTS
  After a median follow-up of 4.82 years, 67 liver cancer and 17 biliary tract cancer patients were diagnosed. Patients who received cholecystectomy had higher risks of liver cancer (SIR, 3.29) and biliary tract cancer (SIR, 8.50). Cholecystectomized patients aged ≤60 years had higher risks of liver cancer (SIR, 11.14) and biliary tract cancer (SIR, 55.86) compared to those aged >60 years (SIR, 2.31 and 5.67). Female cholecystectomized patients had higher risks of liver cancer (SIR, 4.18) and biliary tract cancer (SIR, 10.56) than males (SIR, 2.96 and 7.26). Cholecystectomized patients with cirrhosis had higher SIR of liver cancer than patients without cirrhosis (SIR, 33.84 vs. 1.41).
  
  
  CONCLUSIONS
  Cholecystectomy may be associated with an increased risk of hepato-biliary cancer. Further and regular surveillance should be performed on such patients.
authors.affiliation: Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, 201 Shih-Pai Road, Sec. 2, Taipei, 112, Taiwan.
authors.forename: Wei-Yu
authors.initials: WY
authors.lastname: Kao
authors.forename: Chian-Yaw
authors.initials: CY
authors.lastname: Hwang
authors.forename: Chien-Wei
authors.initials: CW
authors.lastname: Su
authors.forename: Yun-Ting
authors.initials: YT
authors.lastname: Chang
authors.forename: Jiing-Chyuan
authors.initials: JC
authors.lastname: Luo
authors.forename: Ming-Chih
authors.initials: MC
authors.lastname: Hou
authors.forename: Han-Chieh
authors.initials: HC
authors.lastname: Lin
authors.forename: Fa-Yauh
authors.initials: FY
authors.lastname: Lee
authors.forename: Jaw-Ching
authors.initials: JC
authors.lastname: Wu
mesh_terms: D001661:Biliary Tract Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D002763:Cholecystectomy / Q000009:adverse effects*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000453:epidemiology* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018570:Risk Assessment; D013624:Taiwan