Survival Outcome Analysis of Stereotactic Body Radiotherapy and Immunotherapy (SBRT-IO) versus SBRT-alone in Unresectable Hepatocellular Carcinoma (HCC)

Abstract

Introduction While combination of stereotactic body radiotherapy (SBRT) and immunotherapy are promising, their efficacy and safety have not been compared with SBRT-alone in patients with unresectable HCC. Methods This retrospective study included 100 patients with non-metastatic, unresectable HCC in two hospitals. Eligible patients had tumor nodules ≤ 3 and Child-Pugh liver function score of A5 to B7. Seventy patients received SBRT-alone, and 30 patients underwent combined SBRT and immunotherapy (SBRT-IO). Overall survival (OS), time to progression (TTP), overall response rate (ORR), and toxicity were analyzed. We adjusted for the potential confounding factors using propensity score matching. Results The median tumor size was 7.3 cm (range, 2.6 – 18 cm). Twenty-five (25%) of patients had vascular invasion. Before propensity score matching, the 1-year and 3-year OS rate was 89.9% and 59.8% in the SBRT-IO group and 75.7% and 42.3% in SBRT-alone group (p=0.039). After propensity score matching (1:2), 25 and 50 patients were selected from the SBRT-IO and SBRT-alone group. The 1-year and 3-year OS was 92.0% and 63.9% in the SBRT-IO group versus 74.0% and 43.3% in the SBRT-alone group (p=0.034). The 1-year and 3-year TTP was better in SBRT-IO group (1-year: 68.9% versus 58.9% and 3-year: 61.3% versus 32.5%, p=0.057). The ORR of 88% (CR: 56%, PR: 22%) in SBRT-IO arm was significantly better than 50% (CR: 20%, PR: 30%) in the SBRT-alone arm (p=0.006). Three patients (12%) developed ≥ grade 3 immune-related treatment adverse events (n=2 hepatitis, n=1 dermatitis) leading to permanent treatment discontinuation. Discussion / Conclusion Adding immunotherapy to SBRT resulted in better survival with manageable toxicities. Prospective randomized trial is warranted.