title: Multimodality therapy for locoregional extrahepatic cholangiocarcinoma: a population-based analysis.
abstract: BACKGROUND
  Although surgical resection is the mainstay of treatment for extrahepatic cholangiocarcinoma, the majority of patients present with advanced disease. Due in part to numeric rarity, the optimum role of radiotherapy (RT) for extrahepatic cholangiocarcinoma, as well as its relative benefit, is an area of debate. The specific aim of this series was to estimate survival for extrahepatic cholangiocarcinoma patients receiving surgery and adjuvant RT using a robust population-based data set.
  
  
  METHODS
  Data were extracted from the Surveillance, Epidemiology, and End Results (SEER) limited-use data set for selected extrahepatic cholangiocarcinoma cases. Lognormal multivariate survival analysis was implemented to estimate survival for patients for treatment cohorts based on extent of surgical intervention and RT.
  
  
  RESULTS
  Parametric estimated median survival for patients receiving total/radical resection + RT was 26 months; it was 25 months for total/radical resection alone, 25 months for subtotal/debulking resection + RT, 21 months for subtotal/debulking resection, 12 months for RT alone, and 9 months for those not receiving surgery or RT. Parametric multivariate analysis revealed age, American Joint Committee on Cancer Stage, grade, and surgical/radiation regimen as statistically significant covariates with survival. Surgery alone and adjuvant RT cohorts demonstrated evidence of improved survival compared with no treatment; comparatively, RT alone was associated with survival decrement. Early improvement in survival in adjuvant cohorts was not observed at later time points.
  
  
  CONCLUSIONS
  Survival estimates using SEER data suggest an early survival advantage for adjuvant RT for patients with locoregional extrahepatic cholangiocarcinoma. Although future prospective series are needed to confirm these observations, SEER data represent the largest domestic population-based extrahepatic cholangiocarcinoma cohort, and may provide useful baseline survival estimates for future studies.
authors.affiliation: Department of Radiation Oncology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA. fullercd@uthscsa.edu
authors.forename: Clifton D
authors.initials: CD
authors.lastname: Fuller
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Wang
authors.forename: Mehee
authors.initials: M
authors.lastname: Choi
authors.forename: Brian G
authors.initials: BG
authors.lastname: Czito
authors.forename: John
authors.initials: J
authors.lastname: Cornell
authors.forename: Tania M
authors.initials: TM
authors.lastname: Welzel
authors.forename: Katherine A
authors.initials: KA
authors.lastname: McGlynn
authors.forename: Join Y
authors.initials: JY
authors.lastname: Luh
authors.forename: Charles R
authors.initials: CR
authors.lastname: Thomas
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery*; D018281:Cholangiocarcinoma / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery*; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018714:Radiotherapy, Adjuvant / Q000401:mortality; D016019:Survival Analysis