Stereotactic body radiotherapy dose and its impact on local control and overall survival of patients for locally advanced intrahepatic and extrahepatic cholangiocarcinoma

Purpose: Non-resectable cholangiocarcinoma (CCC) is a significant therapeutic challenge because of bad prognosis. This study analyzed the outcome after SBRT for intra-and extrahepatic CCC. Material and methods: Sixty-four patients with 82 CCC lesions from a retrospective multicenter database were analyzed. Available parameters were analyzed for local control (LC), overall survival (OS) and toxicity. Results: Median follow-up time for patients alive was 35 months (range 7-91 months). Median overall survival (OS) time was 15 months; 2-year and 3-year OS rates were 32% and 21%. Median prescribed biological effective radiation dose (BED, alpha/beta = 10) was 67.2 Gy(10) (range, 36-115 Gy(10); SD: 20 Gy(10)) in median 8 fractions (range, 3-17; 95% CI: 3-12), median BEDmax was 91 Gy(10). BED was the only prognostic factor for LC and OS. Patients receiving BEDmax >91 Gy(10) had a median OS of 24 months vs. 13 months for those receiving lower doses (p = 0.008). LC rates at 12 and 24 months were 91% and 80% for BEDmax > 91 Gy(10) vs. 66% and 39% for lower doses (p = 0.009). Of note, tumor size and PTV were neither predictive nor prognostic for LC and OS. Treatment tolerance was good with 17% of grade 1 gastroduodenitis, 11% of grade 2-3 cholangitis and 4.7% of grade 3 gastrointestinal bleeding. Conclusion: This is the largest reported series on SBRT in cholangiocarcinoma. Overall survival and local control were significantly improved after higher doses (BED) and tolerance was excellent. (C) 2018 Elsevier B.V. All rights reserved