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

SIMPLE SUMMARY: The concept of oligometastasis has not been widely shared in the hepatocellular carcinoma (HCC). This study is a multi-institutional retrospective study. We reviewed the data of patients who received SABR for HCC. The results showed that SABR for all metastatic lesions appeared to be an effective and safe treatment for oligometastatic HCC. The median OS for all patients was 16 months, with a 2-year OS rate of 40%. Long-term survival is expected in patients with good performance status and liver function. ABSTRACT: 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.