Efficacy and safety of subsequent radiotherapy in patients with advanced-stage hepatocellular carcinoma treated with immune checkpoint inhibitors

Background: This study aimed to evaluate the efficacy and safety of subsequent radiotherapy (RT) for patients with advanced-stage hepatocellular carcinoma (HCC) who had lesion enlargement or new lesions (NLs) during immune checkpoint inhibitor (ICI) therapy. Methods: This retrospective observational study enrolled 36 patients with advanced-stage HCC who underwent subsequent RT for lesion enlargement or NLs during ICI therapy from two centers. The primary endpoints were progression-free survival (PFS) and overall survival (OS). The secondary endpoints included objective response rate (ORR), disease control rate (DCR), 1-and 2-year local control (LC) rates, in-field PFS (IFPFS), out-field PFS (OFPFS), and safety.Results: The median follow-up time was 15.3 months. The median PFS was 7.4 months [95% confidence interval (CI): 3.1-11.7 months], and the median OS was 18.8 months (95% CI: 17.1-20.5 months). ORR and DCR were 38.9% and 72.2%, respectively. In addition, the median IFPFS was 17.8 months (95% CI: 11.5-24.2 months), median OFPFS was 7.9 months (95% CI: 3.4-12.5 months), and estimated 1-and 2-year LC rates were 67.1% and 31.9%, respectively. The most common treatment-related adverse events (all grades) were diarrhea (33.3%), rash (30.6%), and malaise (27.8%); a total of 14 (38.9%) patients developed grade 3-4 AEs. Conclusions: Subsequent RT showed reliable antitumor effects and an acceptable safety profile in patients with advanced-stage HCC who had unsatisfactory response to ICI therapy; therefore, it could serve as an optional salvage strategy.