Tailored proton beam therapy for hepatocellular carcinoma: Addressing unmet needs through a multidisciplinary approach.

[BACKGROUND] Since December 2015, the Proton Beam Therapy (PBT) center at Samsung Medical Center has treated 2000 cases involving 1823 patients with HCC who were ineligible for Barcelona Clinic Liver Cancer (BCLC) guideline-recommended standard treatments. This study evaluated clinical outcomes and explored the potential role of PBT as an alternative local modality.

[METHODS] We retrospectively reviewed patients with HCC treated with PBT. The primary endpoint was freedom from local progression (FFLP), and the secondary endpoints were overall survival (OS) and toxicity.

[RESULTS] The annual number of PBT cases increased, among all cases, 93.0 % targeted intrahepatic lesions, while 7.0 % targeted extrahepatic lesions. FFLP was evaluated in intrahepatic cases with a median follow-up of 19.5 months (interquartile range [IQR], 8.5-39.7). The 2-year FFLP exceeded 90 % across the treatment periods without significant differences (P = 0.51). According to the BCLC stages (0, A, B, and C), the 2-year FFLP rates were 95.5 %, 93.9 %, 98.5 %, and 87.6 %, respectively, and the 3-year FFLP rates were 91.1 %, 91.3 %, 95.0 %, and 83.3 %, respectively (P < 0.001). The median OS follow-up was 18.7 months (IQR 7.9-38.6). The 3-year OS rates were 81.1 % in BCLC stage 0; 65.5 %, stage A; 45.5 %, stage B; and 37.2 %, stage C, respectively (P < 0.001).

[CONCLUSION] This large, single-center study demonstrated that PBT provided favorable local control and survival outcomes, supporting its role as a promising local ablative modality to address the unmet therapeutic needs in HCC.