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Abstract Background Radiation-induced liver damage (RILD) occasionally occurs following carbon-ion radiotherapy (CIRT) for liver tumors, such as hepatocellular carcinoma (HCC), in patients with impaired liver function disease. However, the associated risk factors remain unknown. The present study aimed to determine the risk factors of RILD after CIRT. Methods We retrospectively analyzed 108 patients with HCC treated with CIRT at the Osaka Heavy Ion Therapy Center between December 2018 and December 2022. RILD was defined as a worsening of two or more points in the Child–Pugh score within 12 months following CIRT. The median age of the patients was 76 years (range 47–95 years), and the median tumor diameter was 41 mm (range 5–160 mm). Based on the pretreatment liver function, 98 and 10 patients were categorized as Child–Pugh class A and B, respectively. We analyzed patients who received a radiation dose of 60 Gy (relative biological effectiveness RBE) in four fractions. The median follow-up period was 9.7 months (range 2.3–41.1 months), and RILD was observed in 11 patients (10.1%). Results Multivariate analysis showed that pretreatment Child–Pugh score B ( p = 0.003, hazard ratio HR = 6.90) and normal liver volume spared from < 30 Gy RBE (VS 30 < 739 cm 3 ) ( p = 0.009, HR = 5.22) were significant risk factors for RILD. The one-year cumulative incidences of RILD stratified by Child–Pugh class A or B and VS 30 < 739 cm 3 or ≥ 739 cm 3 were 10.3% or 51.8% and 39.6% or 9.2%, respectively. Conclusion In conclusion, the pretreatment Child–Pugh score and VS 30 of the liver are significant risk factors for RILD following CIRT for HCC.
Hayashi et al. (Mon,) studied this question.