title: Risk of cancer in patients with cholecystitis: a nationwide population-based study.
abstract: OBJECTIVE
  The objective of this study was to evaluate the risk of cancer in patients diagnosed with cholecystitis and possible interactions between cholecystitis and cholecystectomy.
  
  
  METHODS
  A retrospective population-based cohort study was conducted among patients diagnosed with cholecystitis that were registered in the National Health Insurance Research Database in Taiwan between January 1, 2000 and December 31, 2010. Standardized incidence ratios (SIRs) were calculated to compare the incidence of cancer in these patients to that of the general population. Adjusted hazard ratios (HRs) were also calculated to investigate whether cholecystitis increased the risk for specific cancers.
  
  
  RESULTS
  During a median observation period of 5.4 years, 1541 cancers occurred in 20,431 patients with cholecystitis, yielding a SIR of 1.97 (95% confidence interval [CI], 1.88-2.07). A significantly greater risk of biliary tract cancer (adjusted HR 1.72; 95% CI, 1.08-2.75) was observed after adjusting for potential risk factors. In contrast, cholecystectomy was found to attenuate the cancer risk, with the reduction of adjusted HR from 2.34 (95% CI, 1.62-3.37) to 1.28 (95% CI, 0.76-2.14).
  
  
  CONCLUSIONS
  Cholecystitis is an independent risk factor to extrahepatic biliary tract cancers, whereas cholecystectomy can attenuate the cancer risk of cholecystitis.
authors.affiliation: Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, Taiwan.
authors.forename: Pei-Chang
authors.initials: PC
authors.lastname: Lee
authors.affiliation: School of Medicine, National Yang-Ming University, Taipei, Taiwan; Cancer Center, Taipei Veterans General Hospital, Taipei, Taiwan; Institute of Public Health, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Yu-Wen
authors.initials: YW
authors.lastname: Hu
authors.affiliation: School of Medicine, National Yang-Ming University, Taipei, Taiwan; Cancer Center, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Psychiatry, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
authors.forename: Li-Yu
authors.initials: LY
authors.lastname: Hu
authors.affiliation: Division of Hematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, Taiwan.
authors.forename: San-Chi
authors.initials: SC
authors.lastname: Chen
authors.affiliation: Division of Hematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, Taiwan.
authors.forename: Sheng-Hsuan
authors.initials: SH
authors.lastname: Chien
authors.affiliation: Department of Psychiatry, Chiayi Branch, Taichung Veterans General Hospital, Taichung, Taiwan; Department of Information Management, National Chung-Cheng University, Chiayi, Taiwan.
authors.forename: Cheng-Che
authors.initials: CC
authors.lastname: Shen
authors.affiliation: Department of Family Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Chiu-Mei
authors.initials: CM
authors.lastname: Yeh
authors.affiliation: Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, Taiwan; School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Chun-Chia
authors.initials: CC
authors.lastname: Chen
authors.affiliation: Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, Taiwan; School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Han-Chieh
authors.initials: HC
authors.lastname: Lin
authors.affiliation: School of Medicine, National Yang-Ming University, Taipei, Taiwan; Cancer Center, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Sang-Hue
authors.initials: SH
authors.lastname: Yen
authors.affiliation: School of Medicine, National Yang-Ming University, Taipei, Taiwan; Division of Hematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, Taiwan.
authors.forename: Cheng-Hwai
authors.initials: CH
authors.lastname: Tzeng
authors.affiliation: Institute of Public Health, National Yang-Ming University, Taipei, Taiwan; Department of Family Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Tzeng-Ji
authors.initials: TJ
authors.lastname: Chen
authors.affiliation: School of Medicine, National Yang-Ming University, Taipei, Taiwan; Institute of Public Health, National Yang-Ming University, Taipei, Taiwan; Division of Hematology and Oncology, Department of Medicine, Taipei Veterans General Hospital, Taiwan. Electronic address: chiajenliu@gmail.com.
authors.forename: Chia-Jen
authors.initials: CJ
authors.lastname: Liu
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001661:Biliary Tract Neoplasms / Q000453:epidemiology / Q000209:etiology; D002763:Cholecystectomy / Q000706:statistics & numerical data; D002764:Cholecystitis / Q000150:complications* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology
keywords: Cancer risk; Cholecystectomy; Cholecystitis