Improved oncologic outcomes by ablative radiotherapy in patients with bone metastasis from hepatocellular carcinoma

Purpose: For bone metastasis from hepatocellular carcinoma (HCC), radiotherapy (RT) has been used a palliative treatment with little impact on survival. Currently, ablative RT is popularly used, and a more than palliative effect is expected. Herein, we investigated the clinical efficacy of ablative RT in patients with bone metastasis from HCC. Methods: In total, 530 patients with 887 lesions treated in 1992-2019 were reviewed. Oligometastasis was defined as the presence of < 5 lesions. Total doses were normalized to obtain biologically effective doses (BEDs). The cut-off threshold of the BED was determined via receiver operating characteristics curve analysis. The Kaplan-Meier method was used to calculate overall survival (OS); propensity score matching (PSM) was performed to balance the heterogeneity in cases while comparing BEDs of ≥ 60 and < 60 Gy. Results: The most common site of metastasis was the spine (59%); 59 patients (11%) presented with oligometastasis, and 76.2% of patients showed objective pain palliation after RT. Median OS was 5.1 months for all patients; patients with oligometastasis showed longer OS than those without (9.8 vs. 4.7 months). A Cox proportional hazards model showed that performance status, Child-Pugh class, extraosseous metastasis, primary HCC status, α-fetoprotein level, and radiation dose (BED) were significant prognostic factors. Post PSM, BED was the only treatment-related prognostic factor that remained significant; the median OS durations were 8.1 and 4.4 months when the BEDs were ≥ 60 and < 60 Gy, respectively. Conclusion: Ablative RT improved OS and pain palliation in patients with bone metastasis from HCC.restrictio