Stereotactic Ablative Body Radiotherapy Versus Microwave Ablation for the Treatment of Early‐Stage Hepatocellular Carcinoma

BACKGROUND: Stereotactic ablative body radiotherapy (SABR) shows promise as curative therapy for early-stage hepatocellular carcinoma (HCC). We retrospectively assessed the efficacy of SABR and microwave ablation (MWA) in a multi-centre Australian cohort, comparing local recurrence (LR), mortality, and toxicity. METHODS: This was a retrospective cohort study of 215 early stage HCC tumours treated with SABR across 4 referral centres. Cohort comparison was made to single centre data of MWA in 121 tumours. RESULTS: The main aetiologies of liver disease were hepatitis C and alcohol. The SABR cohort had higher prior HCC treatment (70% vs. 48%; p < 0.001), and more tumours > 2 cm (58% vs. 40%; p = 0.002). LR in the SABR cohort were 4.9% and 6.2% at 1 and 2 years respectively. LR rates in the MWA cohort were 12.4% and 17.3% at 1 and 2 years respectively (p = 0.006). After adjustment for age, sex, MELD, previous HCC treatment, tumour size, and AFP, the SABR cohort had reduced risk of LR compared to MWA (aHR 0.24; 95% CI 0.1-0.58, p = 0.001). Survival was higher in the MWA cohort to the SABR cohort (p < 0.001) despite higher rates of LR. Treatment related complications were common, but mild. Serious adverse events (AE) were rare in both groups. CONCLUSION: SABR demonstrated reduced LR compared to MWA in HCC tumours > 2 cm. The worse survival rates in the SABR cohort may reflect patient factors independent of HCC. Our study findings provide further justification for randomised-controlled trials investigating SABR as primary treatment for early-stage HCC.