Stereotactic Ablative Radiotherapy for Oligometastatic Hepatocellular Carcinoma: A Multi-Institutional Retrospective Study (KROG 20-04).

We investigated the clinical efficacy of stereotactic ablative radiotherapy (SABR) in patients with oligometastatic hepatocellular carcinoma (HCC). The inclusion criteria were patients receiving definitive treatment for HCC with 1-5 metastatic lesions, <3 metastases in a single organ and receiving radiotherapy with fraction doses ≥6 Gy. A total of 100 patients with 121 metastatic lesions were reviewed. The most common site of metastasis was the bones (40%), followed by the lungs (38%). Systemic therapy was administered to 71% of patients. With a median follow-up of 13 months, the median overall survival (OS) was 16 months. The 2-year OS rate was 40%. The prognostic factors in univariate analysis were performance status, Child-Pugh class, primary HCC status, and time interval of metastasis. Performance status and Child-Pugh class remained in multivariate analysis. OS differed significantly depending on the number of prognostic factors: 46 months in patients with both factors (Group 1), 13 months with one factor (Group 2), and 6 months with no risk factor (Group 3) ( p < 0.001). Nine patients experienced grade 1 radiation pneumonitis. Given its efficacy and safety, SABR deserves active consideration in the treatment of oligometastatic HCC.