Single-institutional analysis of radiotherapy and orthotopic liver transplant for patients with unresectable cholangiocarcinoma.

Abstract

466 Background: There is increasing interest in effective strategies for locoregional therapy for cholangiocarcinoma, particularly given the evolving role of orthotopic liver transplant (OLT) for select patients. This single-institution retrospective study compares the clinical efficacy and toxicity of stereotactic body radiotherapy (SBRT), conventional fractionation chemoradiation (CRT), or SBRT as a bridge to OLT in patients with unresectable early stage and locally advanced cholangiocarcinoma. Methods: We reviewed a total of 31 patients from 2010 to 2023 with intrahepatic cholangiocarcinoma (ICC), extrahepatic cholangiocarcinoma (ECC), and perihilar cholangiocarcinoma who were treated with SBRT (n=22) or CRT (n=9). SBRT was delivered in 1-5 fractions, median dose of 40 Gy, and dose ranging from 16 Gy to 60 Gy. CRT was delivered in 13-28 fractions, median dose of 50.2 Gy, and dose ranging from 45 Gy to 52.5 Gy. Kaplan-Meier was used to analyze overall survival (OS), progression-free survival (PFS), and local control (LC). Acute and late G3+ toxicity was scored using CTCAE, version 5.0. Results: We identified 13 patients with ICC, 5 with ECC, and 13 with perihilar disease where SBRT or CRT was part of upfront definitive treatment. With a median follow-up time of 11 months, there was no statistical difference between SBRT vs. CRT for OS (median 21 vs. 22 months; p=0.36), PFS (median 14.2 vs. 11 months; p=0.09), and 1-year LC (73.2% vs. 66.7%; p=0.10). However, SBRT appeared to have lower proportions of acute grade 3+ (9.1% vs. 33.3%) and chronic grade 3+ toxicities (22.7% vs. 33.3%). Four patients with early stage perihilar or ICC underwent SBRT as successful bridge to transplant, with no evidence of disease progression at 5.4 months. An additional 2 out of 8 patients were removed from protocol due to disease progression and 2 others remain on protocol, awaiting OLT. Conclusions: In our series of unresectable cholangiocarcinoma, we found no difference in OS, PFS, and LC for patients treated with SBRT vs. CRT, although the former appeared to have lower toxicity and a trend towards improved PFS. Further research is needed to compare SBRT and CRT as definitive treatment or bridge to OLT for patients with unresectable cholangiocarcinoma.