Impact of Intrahepatic External Beam Radiotherapy in Advanced Hepatocellular Carcinoma Patients Treated with Tyrosine Kinase Inhibitors.

Introduction: We aimed to investigate whether concurrent use of intrahepatic external beam radiotherapy (EBRT) is a viable option for patients with advanced hepatocellular carcinoma (HCC) undergoing tyrosine kinase inhibitor (TKI) therapy.

Methods: A total of 453 patients with Barcelona Clinic Liver Cancer stage C (BCLC C) HCC, who started first-line treatment with TKI with intrahepatic EBRT (TKI + RT, = 97) or TKI without intrahepatic EBRT (TKI, = 356) were analyzed. The overall survival (OS) and progression-free survival (PFS) were compared in the overall cohort, patients who received at least 8 weeks of TKI treatment and a propensity score-matched cohort.

Results: OS and PFS were better in those treated with TKI + RT than TKI (8.6 vs. 4.4 months and 4.5 vs. 2.3 months, respectively, with < 0.001). Of note, the TKI + RT group demonstrated significantly longer time to intrahepatic tumor progression. In subgroup analysis, TKI + RT led to better OS than TKI in all subgroups and PFS was significantly improved in patients without extrahepatic metastasis and those with portal vein invasion. There was no significant difference in treatment discontinuation due to adverse events between the TKI + RT and TKI groups (32.0% vs. 37.9%, = 0.34). Furthermore, patients treated with TKI + RT showed better liver function preservation over time compared to TKI without intrahepatic EBRT. Comparable treatment outcomes were observed between patients who received at least 8 weeks of TKI treatment and the propensity score-matched cohort.

Conclusion: Concurrent intrahepatic EBRT targeting the liver and/or macrovascular invasion can be a viable option to improve outcomes of BCLC stage C patients receiving TKI therapy with an aim to control intrahepatic progression and preserving the liver function.