title: Postoperative radiotherapy appeared to improve the disease free survival rate of patients with extrahepatic bile duct cancer at high risk of loco-regional recurrence.
abstract: OBJECTIVE
  To investigate the outcomes of postoperative radiotherapy (RT), in patients with extrahepatic bile duct (EHBD) cancer by comparing the survival rate between patients undergoing surgery alone or surgery plus postoperative RT, and to identify the prognostic factors affecting survival.
  
  
  METHODS
  Between 2000 and 2013, 52 patients with EHBD cancer underwent surgical resection. Of these, 33 patients did not receive postoperative RT (group I), and 19 patients did (group II). R1 resection was significantly more frequent in group II. The median radiation dose was 5,040 cGy.
  
  
  RESULTS
  The 3-year overall survival (OS) rate for group I and group II was 38% and 56%, respectively (p = 0.274). The 3-year disease free survival (DFS) rate for group I and group II was 20% and 31%, respectively (p = 0.049), and the 3-year loco-regional recurrence free survival (LRFS) rates were 19% and 58%, respectively (p = 0.002). Multivariate analyses showed that postoperative RT and lymphovascular invasion were independent prognostic factors for DFS and LRFS. Overall, 42 patients (80%) experienced treatment failure. Distant metastasis was the predominant pattern of failure in group II.
  
  
  CONCLUSIONS
  Postoperative RT after surgical resection appeared to improve the loco-regional control and DFS rate. More effort is needed to reduce distant metastasis, the major pattern of failure, in patients who receive postoperative RT.
authors.affiliation: Department of Radiation Oncology, Keimyung University Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Korea.
authors.forename: Mi Young
authors.initials: MY
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Keimyung University Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Korea.
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Surgery, Keimyung University Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Korea.
authors.forename: Yonghoon
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Sang Jun
authors.initials: SJ
authors.lastname: Byun
keywords: Extrahepatic bile duct cancer; Postoperative; Radiotherapy; Survival