Objectives: The purpose of this study is to evaluate the result of stereotactic body radiotherapy (SBRT) using Cyberknife® System for unresectable advanced cholangiocarcinoma.

Methods: From September 2008 to October 2015, 34 Patients with unresectable localregional advanced (n=13) or recurrent (n=21) cholangiocarcinoma were included in this retrospective study. SBRT was delivered in a total dose of 40-50Gy in 3-8 fractions. The primary end point was local control rate after SBRT. Secondary end points were overall survival, progression-free survival, and toxicity, assessed using the Common Terminology Criteria for Adverse Events version 4.0.

Results: 34 paitents (36 lesions) with advanced cholangiocarcinoma were included. The median follow-up time were 14 months. The 1-year and 2-years actuarial LC rates were 89% and 79%, respectively. The 1-year OS and PFS rate were 59% and 39%, and the median OS and PFS were 13.9 and 10 months. The median survival for primary tumor and recurrence were 13.5 and 14.8 months, respectively. Univariate analysis showed that tumor size (<3.5cm) and receipt of systemic chemotherapy was associated with improved OS and PFS regardless of primary or recurrence tumor.

Conclusions: SBRT can be considered as an effect local modality for unresectable advanced cholangiocarcinoma. The combination of SBRT with chemotherapy may be more beneficial than SBRT alone.