title: Radiotherapy is associated with improved survival in adjuvant and palliative treatment of extrahepatic cholangiocarcinomas.
abstract: OBJECTIVE
  Extrahepatic cholangiocarcinomas (EHC) are rare tumors of the biliary tree because of their low incidence, large randomized studies examining radiotherapy (RT) for EHC have not been performed. The purpose of this study was to examine the role of adjuvant and palliative RT in the treatment of EHC in a large patient population.
  
  
  METHODS
  This was a retrospective analysis of 4,758 patients with EHC collected from the Surveillance, Epidemiology, and End Results database. The primary endpoint was overall survival.
  
  
  RESULTS
  Patients underwent surgery (28.8%), RT (10.0%), surgery and RT (14.7%), or no RT or surgery (46.4%). The median age of the patient population was 73 years (range, 23-104), 52.5% were men, and 80.7% were white. The median overall survival time was 16 months (95% confidence interval [CI] 15-17), 9 months (95% CI 9-11), 9 months (95% CI 9-10), and 4 months (95% CI 3-4) for surgery and RT, surgery, RT, and no RT or surgery, respectively. The overall survival was significantly different between the surgery and surgery and RT groups (p < .0001) and RT and no RT or surgery groups (p < .0001) on the log-rank test. The propensity score-adjusted analyses of surgery and RT vs. surgery (hazard ratio, 0.94; 95% CI, 0.84-1.05) were not significantly different, but that for RT vs. no RT or surgery (hazard ratio, 0.61; 95% CI, 0.54-0.70) was significantly different.
  
  
  CONCLUSIONS
  These results suggest that palliative RT prolongs survival in patients with EHC. The benefit associated with surgery and RT was significant on univariate analysis but not after controlling for potential confounders using the propensity score. Future studies should evaluate the addition of chemotherapy and biologic agents for the treatment of EHC.
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA. shinohara@xrt.upenn.edu
authors.forename: Eric T
authors.initials: ET
authors.lastname: Shinohara
authors.forename: Nandita
authors.initials: N
authors.lastname: Mitra
authors.forename: Mengye
authors.initials: M
authors.lastname: Guo
authors.forename: James M
authors.initials: JM
authors.lastname: Metz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001650:Bile Duct Neoplasms / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D017734:Bile Ducts, Extrahepatic / Q000601:surgery; D018281:Cholangiocarcinoma / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010166:Palliative Care; D018714:Radiotherapy, Adjuvant / Q000401:mortality; D012189:Retrospective Studies; D018426:SEER Program; D016019:Survival Analysis; D055815:Young Adult