Multicenter prospective study of stereotactic body radiotherapy for previously untreated solitary primary hepatocellular carcinoma: The STRSPH study.

AIM: To prospectively evaluate the efficacy and safety of stereotactic body radiotherapy (SBRT) for patients with previously untreated solitary primary hepatocellular carcinoma (HCC).

METHODS: The main eligibility criteria included the following: (1) primary solitary HCC; (2) no prior treatment for HCC; (3) Child-Turcotte-Pugh score of seven or less; and (4) unsuitability for or refusal of surgery and RFA. The prescribed dose of SBRT was 40 Gy in five fractions. The primary endpoint was three-year overall survival (OS); the secondary endpoints included local progression-free survival (LPFS), local control (LC), and adverse events. The accrual target was 60 patients, expecting a three-year OS of 70% with a 50% threshold.

RESULTS: Between 2014 and 2018, 36 patients were enrolled; enrolment was closed early because of slow accrual. The median tumor size was 2.3 cm. The median follow-up at the time of evaluation was 20.8 months. The three-year OS was 78% (95% confidence interval [CI]: 53-90%). The three-year LPFS and LC proportion were 73% (95% CI: 48-87%) and 90% (95% CI: 65-97%), respectively. Grade 3 or higher SBRT-related toxicities were observed in four patients (11%), and grade 5 toxicities were not observed.

CONCLUSIONS: This study showed acceptably low incidence of SBRT-related toxicities. LC and OS after SBRT were comparable for previously untreated solitary HCC for patients unfit for resection and RFA. Although a definitive conclusion cannot be drawn by this study, the promising results indicate that SBRT may be an alternative option in the management of early HCC.