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Management of HCC is challenging as liver cirrhosis, comorbidities and tumor location can limit the choice of treatment modality. The majority of patients will be ineligible for resection or transplantation and several factors including tumor size and location impact on the feasibility and efficacy of thermal ablation or transarterial therapies. SBRT has demonstrated high rates of local control in multiple series, however, few studies have reported on SBRT specifically in the treatment naïve, curative intent setting.  We report the outcomes of patients with solitary early-stage HCC treated with SBRT as first line definitive therapy.

This is a multi-institutional retrospective study between 2010 and 2019 of patients with a new diagnosis of BCLC stage 0/A HCC and a single ≤5cm lesion, Child-Pugh (CP) A compensated liver function who underwent SBRT as first line, curative intent therapy.  The primary end point was freedom from local progression (FFLP). Secondary end points were progression-free survival (PFS), overall survival (OS) and treatment related toxicity.

68 patients met inclusion criteria with a median follow-up of 20 months (range, 3-58). Median age was 68 years (range, 50-86), 54 (79%) were male, 62 (91%) had cirrhosis and 50 (74%) patients were ECOG 0. The predominant etiologies of liver cirrhosis were NAFLD (48%), HCV (35%) and ALD (34%). Median HCC diameter was 2.6cm (range, 1.3-5) and serum AFP was 5.1 (range, 1.5-2275). Median prescription BED10 dose was 93Gy (range, 48-125Gy). The 2-year FFLP, PFS and OS were 94%, 60% and 88%, respectively. Two patients had local failures and did not undergo further treatment due to decline in general and hepatic function unrelated to SBRT. The predominant cause of disease progression was out-of-field intrahepatic relapse, occurring in 16 patients. Of those patients, 13 (81%) patients underwent additional liver directed therapy, 1 patient commenced systemic therapy and 2 patients received best supportive care in light of co-morbidities. Grade 2 and 3 clinical toxicity (excluding asymptomatic biochemical and hematological) was reported in 9 (13.2%) and 0 (0%) patients, respectively. A rise of ≥2 in CP-score was observed in six patients with cirrhosis (9.6%) within 3 months of SBRT.

SBRT is a well-tolerated, definitive first-line treatment option in patients with BCLC stage 0/A, single HCC with high rates of local control and warrants further study in the treatment naïve setting. The ongoing multicentre TROG 21-07 study is randomising non-surgical patients with solitary HCC ≤3cm to SBRT or thermal ablation and an additional “ablation ineligible” cohort with HCC ≤5cm to SBRT or transarterial therapies (ACTRN1262100144875).