ESTRO 2024 - Abstract Book

S2240

Clinical - Upper GI

ESTRO 2024

2260

Digital Poster

Pencil beam scanning proton beam therapy for huge (>10cm) hepatocellular carcinoma.

Jen-Yu Cheng 1 , Yu-Ming Wang 1,2 , Eng-Yen Huang Huang 1,2 , Meng-Wei Ho 1,3 , Fang-Jing Li 1 , Bing-Shen Huang 3,1

1 Kaohsiung Chang Gung Memorial Hospital, Radiation Oncology, Kaohsiung, Taiwan. 2 Chang Gung University College of Medicine, School of Traditional Chinese Medicine, Taoyuan, Taiwan. 3 Linkou Chang Gung Memorial Hospital, Radiation Oncology, Taoyuan, Taiwan

Purpose/Objective:

The prognosis for unresectable large (>10cm) hepatocellular carcinoma (HCC) is poor. Currently, effective treatment methods for such patients are limited. Proton beam therapy (PBT) has shown promise in achieving favorable local control while preserving adequate liver function. This study aims to assess the clinical efficacy of PBT for patients with large HCC.

Material/Methods:

A retrospective analysis was conducted on patients with unresectable non-metastatic huge (>10cm) HCC from September 2019 to November 2021 at Kaohsiung Chang Gung Memorial Hospital (K-CGMH) and Linkou Chang Gung Memorial Hospital (LK-CGMH). Pencil beam scanning proton beam therapy was administered to irradiate gross tumor to a dose of 72.6 Gy (relative biological effectiveness) in 22 fractions. Respiratory management techniques, including abdominal compression and respiratory gating, were employed to reduce respiratory motion based on breathing amplitude. Daily cone beam computed tomography (CBCT) imaging was utilized for patient setup and tracking the anatomy changes. Regular adaptive planning was performed at intervals exceeding 3-5 weeks from the simulation. The study outcomes, including local control and overall survival, were evaluated using Kaplan-Meier analysis. The response rate was determined according to modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria. Gastrointestinal (GI) and liver toxicities were also assessed.

Results:

A total of 64 patients were enrolled, with a median follow-up period of 15.9 months. The median sizes of the largest and cumulative tumors were 12.9 cm and 15 cm, respectively. Forty-eight percent of the patients (31) presented with portal vein tumor thrombosis, with 24 patients classified as Japanese Vp 3 or 4, and 19 patients received concurrent target and/or immunotherapy. 45.3% of patients (29) had multiple lesions, while 10.9% (7) had regional lymph node metastasis. The one and 2-year local control rates were 92.0% and 82.6%, respectively, and the one and 2-year overall survival rates were 83.4% and 58.7%, respectively. The median survival was not reached. The tumor response rate (including complete and partial response) was 90.6%. There were two cases (3.1%) of Grade 3 GI toxicities requiring endoscopic intervention and a 6.7% risk of radiation-induced liver disease.