title: The role of postoperative radiation therapy (PORT) in the treatment of extrahepatic bile duct cancer: a surveillance, epidemiology, and end results (SEER) population-based investigation.
abstract: OBJECTIVE
  Extrahepatic bile duct cancers (EBDC) are aggressive cancers for which the importance of the use of postoperative radiation therapy (PORT) in potentially curative cases remains the subject of clinical investigation.
  
  
  METHODS
  The 1973-2004 National Cancer Institute Surveillance Epidemiology and End Results (SEER) database was analyzed for patients with EBDC who had undergone cancer-directed surgery. Patients who died <3 months after surgery were excluded from analysis. Patients with distant metastases, with unknown stage or interventions, or benign histologies were excluded.
  
  
  RESULTS
  Nine hundred fifty-six patients were selected. Tumor-related factors, such as regional (vs. local) disease and an increasing number of lymph nodes predicted for the delivery of PORT. In unadjusted univariate analysis, patients treated from 1973 to 2004 who fit the selection criteria had a lower 3-year survival rate if they received PORT vs. no PORT (3 year survival 31.3% vs. 39.6%, p = 0.04), but this improvement did not hold in multivariate survival analysis or in univariate analysis of patient subsets.
  
  
  CONCLUSIONS
  Based on analysis of the SEER database, there was no definitive evidence for improved survival with the addition of PORT to radical surgery. This analysis should be approached with caution given its observational and retrospective nature. In addition, it should be remembered that the SEER database lacks information on the use of chemotherapy, radiation technique, and the completeness of resection.
authors.affiliation: Department of Therapeutic Radiology, Yale School of Medicine, HRT 133, 333 Cedar St., New Haven, CT 06520, USA.
authors.forename: James B
authors.initials: JB
authors.lastname: Yu
authors.forename: Roy H
authors.initials: RH
authors.lastname: Decker
authors.forename: Jonathan P S
authors.initials: JP
authors.lastname: Knisely
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000401:mortality / Q000628:therapy*; D017734:Bile Ducts, Extrahepatic; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018426:SEER Program