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

Background: The development of immunotherapy resistance is associated with a poor prognosis in patients diagnosed with hepatocellular carcinoma (HCC) who are undergoing treatment with immune checkpoint inhibitors (ICI). This study aimed to evaluate the efficacy and safety of subsequent radiotherapy (RT) for patients with advanced-stage HCC who had lesion enlargement or new lesions (NLs) during 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.