Role of adjuvant radiotherapy in extrahepatic bile duct cancer: A multicenter retrospective study (Korean Radiation Oncology Group 18-14).

Abstract Purpose To evaluate the role of adjuvant radiotherapy (RT) after curative resection in patients with extrahepatic bile duct (EHBD) cancer. Methods Between January 2000 and December 2015, 1475 patients with EHBD cancer who underwent curative resection were accrued from 14 institutions in Korea. Among these, 959 patients did not receive any adjuvant therapy (RT(−) group), while 516 underwent postoperative RT with or without chemotherapy (RT(+) group). Results The median age was 67 years. Nodal involvement was present in 482 patients (32.7%), and resection margin was involved in 293 patients (19.9%). RT(+) group had more patients with proximal tumours, advanced tumours, nodal involvement, perineural invasion, and involved resection margin than RT(−) group (all p  Conclusions Adjuvant RT combined with chemotherapy improved survival outcomes of resected EHBD cancer patients. Considering the greatest benefit observed in patients receiving CCRT followed by chemotherapy, a randomised controlled trial comparing chemotherapy alone and CCRT followed by chemotherapy is urgently needed.