Stereotactic ablative body radiotherapy for previously untreated solitary hepatocellular carcinoma

Background and Aims: Stereotactic ablative body radiotherapy (SABR) is a relatively new treatment for hepatocellular carcinoma (HCC). The outcomes of SABR for previously untreated solitary HCC unfit for ablation and surgical resection were evaluated. Methods: Untreated solitary HCC patients treated with SABR were retrospectively studied. Between 2005 and 2012, 221 HCC patients underwent SABR. Among them, patients with untreated solitary HCC, treated with only SABR or SABR preceded by transarterial chemoembolization, were eligible. Based on baseline liver function and liver volume receiving ≥20Gy, 35-40Gy in five fractions was prescribed to the planning target volume surface. Results: Sixty-three patients were eligible, with a median follow-up duration of 31.1 (range 12.0-88.1) months. No patients were lost to follow-up. Twenty patients were treated with only SABR. In 43 patients treated with SABR preceded by transarterial chemoembolization, accumulation of lipiodol in the tumor remained complete in five, a partial defect in 38 on pre-SABR computed tomography. The 1-, 2-, and 3-year local control rates were 100%, 95%, and 92%, respectively; the intrahepatic recurrence-free rates were 76%, 55%, and 36%, respectively; and the overall survival rates were 100%, 87%, and 73%, respectively. Grade 3 laboratory toxicities in the acute, subacute, and chronic phases were observed in 10, 9, and 13 patients, respectively, and ascites occurred in one patient. Conclusions: Local control and overall survival after SABR for untreated solitary HCC were excellent despite the candidates being unfit for resection and ablation. SABR is safe and might be an alternative to resection and ablation.