Combined Stereotactic Body Radiotherapy and Immunotherapy Versus Transarterial Chemoembolisation in Locally Advanced Hepatocellular Carcinoma: A Propensity Score Matching Analysis

Abstract Immunotherapy has achieved modest clinical activity in HCC patients. Propensity score matching analysis was conducted to compare the efficacy and safety of combined stereotactic SBRT-IO versus TACE in patients with locally advanced HCC in a tertiary centre of Hong KongPatients with locally advanced HCC who were medically inoperable for, refractory to, or refused to curative surgical interventions were eligible. The primary outcome was PFS; the secondary outcomes were OS, ORR as per mRECIST version 1.1, and TRAEs. Matching pair analysis was performed to compare the clinical outcomes.A total of 226 patients were eligible. 16 patients in the SBRT-IO group were matched with 48 patients treated with TACE. The median tumour size was 10 cm (range: 2.9-19.6 cm) and 20.3% of the patients had portal vein invasion. The 12-month and 24-month PFS were significantly better in the SBRT-IO group (93.3% vs 16.7% and 77.8% vs 2.1%, respectively, p<0.001); the 12-month and 24-month OS were also better in the SBRT-IO arm (93.8% vs 31.3% and 80.4% vs 8.3%, respectively, p<0.001). The ORR was 87.5% (CR: 50%, PR: 37.5%) in SBRT-IO arm compared to 16.7% (CR: 2.4%, PR: 14.3%) in those receiving TACE alone (p<0.001). There were fewer ≥ grade 3 TRAE (60.4% vs 18.8%, p=0.004) and treatment discontinuations (25% vs 12.5%, p=0.295) due to adverse events in the SBRT-IO arm.SBRT-IO had significant superior survival and less treatment toxicity than TACE in patients with locally advanced HCC. Our results provide rationale for studying this combination therapy in prospective randomised trials.