Carbon-ion radiotherapy achieves outcomes equivalent to surgical resection for hepatocellular carcinoma.

[AIM] This study aimed to compare the clinical outcomes of carbon-ion radiotherapy (CIRT) to those of surgical resection (SR) in patients with HCC.

[METHODS] This retrospective study included 116 and 947 patients initially receiving CIRT and SR in Japanese institutions from September 2010 and June 2022. We used inverse probability of treatment weighting (IPTW) analysis to correct for imbalances in baseline patient characteristics between the 2 groups.

[RESULTS] The median observation period was 3.3 years (IQR: 1.4-5.8) in the SR group and 2.8 years (IQR: 1.6-4.5) in the CIRT group (p=0.2). Before IPTW analysis, the median recurrence-free survival (RFS) was 2.3 years in the SR group and 2.2 years in the CIRT group, with no statistical significance (p=0.3). After IPTW analysis, the median RFS was 2.5 years in the SR group and 2.3 years in the CIRT group, which remained statistically nonsignificant (p=0.9). The median overall survival (OS) was not reached in the SR group, while it was 7.4 years in the CIRT group. The SR group demonstrated better survival compared to the CIRT group (p=0.02). In the IPTW cohort, the median OS was not reached in the SR group, while it remained 7.4 years in the CIRT group, showing no significant difference (p=0.4). Multivariate analyses showed that treatment choice (SR vs. CIRT) was not identified as a predictive factor for both RFS and OS.

[CONCLUSIONS] CIRT showed no statistically significant differences in RFS or OS compared with SR, suggesting its potential as a curative treatment option for early-stage HCC.