Comparison of carbon ion radiotherapy and transarterial chemoembolization for unresectable solitary hepatocellular carcinoma >3 cm: a propensity score-matched analysis.

Abstract

This study aimed to compare outcomes between carbon ion radiotherapy (C-ion RT) and transarterial chemoembolization (TACE) in patients with unresectable solitary hepatocellular carcinoma (HCC) >3 cm. Fifty-eight patients who had been treated with C-ion RT (C-ion RT group) and 34 treated with TACE (TACE group) were retrospectively enrolled between January 2016 and December 2021. Propensity score matching was conducted to account for differences between the two groups. The median follow-up duration was 42.1 months for all patients. Propensity score matching successfully balanced the two groups with 29 patients matched to each group. The 3-year overall survival (OS), progression-free survival (PFS) and local control (LC) rates in the C-ion RT vs TACE groups were 75.9% vs 45.4%, 44.8% vs 16.1% and 85.2% vs 23.2%, respectively. The C-ion RT group showed better OS (hazard ratio [HR], 0.578 [95% confidence interval (CI): 0.295-1.132]; P = 0.106), PFS (HR, 0.460 [95% CI: 0.254-0.835]; P = 0.009) and LC (HR, 0.155 [95% CI: 0.062-0.390]; P < 0.001) than the TACE group. Multivariate analysis indicated that C-ion RT was significantly associated with increased PFS (HR, 0.562 [95% CI: 0.341-0.926]; P = 0.024) and LC (HR, 0.282 [95% CI: 0.150-0.528]; P < 0.001). C-ion RT provided better OS, PFS and LC than TACE in patients with solitary HCC >3 cm. This study indicated that C-ion RT is a possible alternative to TACE, which is the standard of care for patients with medium-to-large-sized HCCs.