ESTRO 2025 - Abstract Book

S1815

Clinical – Upper GI

ESTRO 2025

3073

Digital Poster Clinical results of proton beam therapy for patients with HCC: A merit of the BCLC staging on prognosis prediction Takahiro Waki 1,2 , Takeshi Ogata 1 , Dongcun Jin 1 , Kotaro Yoshio 3 , Norihisa Katayama 2 , Kuniaki Katsui 4 , Takao Hiraki 5 1 Department of Radiology, Tsuyama Chuo Hosptal, Tsuyama, Japan. 2 Department of Radiology, NHO Okayama Medical Center, Okayama, Japan. 3 Department of Proton Beam Therapy, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan. 4 Department of Radiology, Division of Radiation Oncology, Kawasaki Medical School, Kurashiki, Japan. 5 Department of Radiology, Faculty of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan Purpose/Objective: To evaluate the efficacy and toxicity of proton beam therapy (PBT) for patients with hepatocellular carcinoma (HCC). To examine the relationship between the Barcelona Clinic Liver Cancer (BCLC) stage and the prognosis of HCC patients treated with PBT. Material/Methods: Retrospective analysis of 63 patients who received PBT between March 2016 to March 2024 was performed. There were 46 males and 17 females, with a median age of 77 years (range, 41-93). Patients received 66.0 Gy (RBE) in 10 fractions for peripheral tumors and 72.6 Gy (RBE) in 22 fractions for central tumors. 11, 19, 7 and 26 cases were classified to 0, A, B and C stage on the BCLC staging system, respectively. 10, 23 and 30 cases had underlying HBV, HCV and other liver disease, respectively. Median serum AFP and platelet level at the start of irradiation were 10.1 IU/ml (range, 1.2-9044.6) and 147.0 10^3/uL (range, 44.0-391.0), respectively. Median mean normal liver dose (MLD) and the proportion of the normal liver receiving ≥ 20 Gy ( NL V 20Gy ) were 1484.0 cGy (range, 402.0-3306.0) and 25.3 % (range, 7.3-54.0), respectively. On UICC 8 th version, clinical T1, T2, T3 and T4 were 36, 9, 7 and 11 cases, respectively. Median ICG-R15 value was 16 % (range, 1-64). 27 cases had the history of prior local therapy of HCC. Results: The median follow-up period was 39.5 months (range, 1.6-89.9 months). The 3-/ 5-year overall survival (OS), disease specific survival (DSS), progression-free survival (PFS), and local control (LC) rates were 71.8/56.1%, 82.7/77.7%, 30.5/27.4%, and 82.9/82.9%, respectively. In multivariate analysis using the Cox proportional hazards model, very early - intermediate stage (BCLC-0, A and B), presence of underlying viral liver disease, low serum AFP level, low MLD and low NL V 20Gy were significantly favorable factors for OS or DSS. Early T-stage, high serum platelet level, low ICG R15 value and non-presence of prior local therapy were significantly favorable factors for PFS. Classic and non classic radiation induced liver damage were observed in 0 and 2 cases, respectively. PBT related Grade 3, 4 and 5 late toxicities were observed in 7, 1 and 0 cases, respectively. Conclusion: PBT was feasible and tolerable for patients with HCC. The BCLC staging was useful for predicting prognosis of HCC patients treated with PBT.

Keywords: Proton beam therapy, HCC, BCLC staging