Dose-Response Relationship in Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma: A Pooled Analysis of an Asian Liver Radiation Therapy Group Study

Abstract

Purpose: Despite the worldwide implementation of stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma (HCC), there is a lack of consensus guideline on prescription dose. Herein, this multinational study aimed to investigate the effects of the prescribed radiation dose on oncologic outcomes of SBRT for HCC.

Methods and Materials: The multi-institutional retrospective cohort included 510 patients treated with SBRT between 2010 and 2016. All relevant clinical factors and factors related to SBRT were analyzed to evaluate freedom from local progression (FFLP) and overall survival (OS). Based on a biologically effective dose (BED) cutoff value of 100 Gy, 198 tumors were selected from each group in propensity score matching (PSM).

Results: Baseline characteristics in the BED <100 Gy group were unfavorable (Child-Pugh class B, 19%; advanced stage, 72%; median tumor size was 4 cm) compared with the BED ≥100 Gy group. With a median follow-up of 22 (interquartile range, 9.8-37.6) months, the 2-year FFLP and OS rates were 77% and 73%, respectively. Patients treated with a BED ≥100 Gy showed better rates of 2-year FFLP and OS than patients treated with a BED <100 Gy (FFLP, 89% vs 69%; OS, 80% vs 67%; P < .001). In the multivariable analysis before and after PSM, BED ≥100 Gy was identified as the main prognostic factor for both FFLP and OS (P < .01). Additionally, a dose-response relationship was observed between FFLP and BED (odds ratio, 0.92 per 5 Gy, P = .048).

Conclusions: A BED ≥100 Gy was significantly associated with outcomes, and a dose-response relationship was observed between local tumor progression and BED. Given that SBRT is being increasingly used in HCC, detailed consensus guidelines regarding SBRT dose prescription should be established.