Prospective Study of Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma on Waitlist for Liver Transplant.

BACKGROUND AND AIMS There are no prospective data on stereotactic body radiation therapy (SBRT) as a bridge to liver transplantation for HCC. This study aimed to evaluate the efficacy and safety of SBRT as bridging therapy, with comparison with transarterial chemoembolization (TACE) and high-intensity focused ultrasound (HIFU). APPROACH AND RESULTS Patients were prospectively enrolled for SBRT under a standardized protocol from July 2015 and compared with a retrospective cohort of patients who underwent TACE or HIFU from 2010. The primary endpoint was tumor control rate at 1 year after bridging therapy. Secondary endpoints included cumulative incidence of dropout, toxicity, and posttransplant survival. During the study period, 150 patients were evaluated (SBRT, n = 40; TACE, n = 59; HIFU, n = 51). The tumor control rate at 1 year was significantly higher after SBRT compared with TACE and HIFU (92.3%, 43.5%, and 33.3%, respectively; P = 0.02). With competing risk analysis, the cumulative incidence of dropout at 1 and 3 years after listing was lower after SBRT (15.1% and 23.3%) compared with TACE (28.9% and 45.8%; P = 0.034) and HIFU (33.3% and 45.1%; P = 0.032). Time-to-progression at 1 and 3 years was also superior after SBRT (10.8%, 18.5% in SBRT, 45%, 54.9% in TACE, and 47.6%, 62.8% in HIFU; P < 0.001). The periprocedural toxicity was similar, without any difference in perioperative complications and patient and recurrence-free survival rates after transplant. Pathological complete response was more frequent after SBRT compared with TACE and HIFU (48.1% vs. 25% vs. 17.9%, respectively; P = 0.037). In multivariable analysis, tumor size <3 cm, listing alpha-fetoprotein <200 ng/mL, Child A, and SBRT significantly reduced the risk of dropout. CONCLUSIONS SBRT was safe, with a significantly higher tumor control rate, reduced the risk of waitlist dropout, and should be used as an alternative to conventional bridging therapies.