ESTRO 2022 - Abstract Book

S1083

Abstract book

ESTRO 2022

Results A total of 45 patients were analyzed: Forty-one patients with hepatocellular carcinomas (91.1%) and four (8.9%) with intrahepatic cholangiocarcinoma. The median of maximum tumor diameter was 29 mm (range: 6-50 mm) and of total tumor diameter (the sum of the diameters of each tumor) was 30 mm (6-72 mm). Two lesions were treated simultaneously in 11 cases (24.6%). The identified factors predicting benefits in PBT differed depending on the selected NTCP model. In the analysis of Child-Pugh grade A cases, the total tumor diameter was a significant factor (p<0.01) in three NTCP models predicting ≥ grade 3 radiation-induced liver disease (RILD). Tumor location (hilum vs others) and number of tumors (1 vs 2) were also significant factors (p<0.01) in the other two models predicting changes in the Child-Pugh score or albumin- bilirubin (ALBI) grade. Around two-thirds of patients with ≥ 2 factors may benefit from PBT in Child-Pugh grade A (Figure)

Conclusion From radiation-related hepatic toxicity considerations, the total tumor diameter, location, and number of tumors were suggested to be important factors to predict benefits of PBT in Child-Pugh grade A cases, with the maximum diameter of ≤ 5 cm. These factors may allow us to predict the benefits of PBT in advance.

PO-1285 Clinical impact of carbon ion radiotherapy for hepatocellular carcinoma with Child-Pugh B cirrhosis

Y. Hiroshima 1 , M. Wakatsuki 2 , T. Kaneko 3 , H. Makishima 4 , H. Ishikawa 1 , H. Tsuji 5

1 QST Hospital, National Institutes for Quantum Science and Technology, Radiotherapy, Chiba city, Japan; 2 QST Hospital, National Institutes for Quantum Science and Technology, Radiotherpy, Chiba city, Japan; 3 Yamagata University Hospital, Radiotherapy, Yamagata city, Japan; 4 University of Tsukuba, Radiotherapy, Tsukuba city, Japan; 5 QST Hospital, National Institutes for Quantum Science and Technology, Radiotherpay, Chiba city, Japan Purpose or Objective The purpose of this study is to evaluate the clinical efficacy of carbon ion radiotherapy (CIRT) for hepatocellular carcinoma (HCC) in patients with group B in the Child-Pugh classification. Materials and Methods Fifty-eight patients and 69 regions with HCC who received CIRT at our hospital from May 2000 to March 2020 were eligible for the study. Their median age was 71 years (range, 49-84), the number of men and women was 36 and 22, and performance status were 0/1/2 in 43/12/3 patients, respectively. The number of patients with a history of HBV/HCV was 7/33, respectively, the median of tumor diameter was 3.2 cm (range, 0.7-13.5 c ｍ ), and vascular invasion was observed in 13 cases. Child-Pugh score was 7/8/9 in 42/13/3 patients, and ALBI score was 1/2a/2b/3 in 1/7/46/4 patients, respectively. The median follow-up period was 20.5 months (range, 2.3-108 months). Dose fractions were 45Gy (RBE)/2fraction (fr) in 9cases, 48Gy (RBE)/2fr in 24, 52.8Gy (RBE)/4fr in 27, and 60Gy (RBE)/4fr in 9, respectively. Results CIRT has been completed as planned for all patients. Until now, 45 patients died, and 43 patients had recurrences including locoregional ones and/or distant metastasis. The 1- and 2- year rates of overall survival (OS), progression-free survival and local recurrence-free rates were 80.4%/46.0%, 38.6%/6.9%, 96.4%/96.4%, respectively. During the observation period, hepatic Grade 3 adverse event of CTCAE was observed in one patient in the acute phase and two patients in the late. No Grade 4 or higher adverse events were observed. The Child-Pugh score worsened after CIRT in 24.1% of patients in the acute phase and 39.7% in the late phase, but worsened from Child-Pugh score B to C in 1.7% of patients in the acute phase and 5.2% in the late phase. In univariate analysis, there was a significant difference in Child-Pugh score before CIRT in OS (p=0.008). Regarding the influence of the worsening of Child-Pugh score after CIRT on OS, worsening in the acute phase