Defining Radiation-Induced Hepatic Toxicity in Hepatocellular Carcinoma Patients Treated with Stereotactic Body Radiotherapy

The definition and criteria of radiation-induced hepatic toxicity (RIHT) in hepatocellular carcinoma patients vary among studies. Therefore, the reported rates of RIHT differ among studies, and this causes confusion. In this study, we evaluated RIHT using several laboratory and clinical parameters, and analyzed which criterion is more correlated with RT and survival. Forty-five HCC patients treated with stereotactic body radiotherapy were included for the analysis. All patients had unresectable HCC and Child-Pugh (CP) class A or B baseline liver function. A median total dose of 45 Gy was delivered by CyberKnife in 3 fractions. For individual laboratory parameter, ≥ grade 2 toxicity development of bilirubin, albumin, or prothrombin time by Common Terminology Criteria of Adverse Effects (CTCAE) was correlated with mean liver dose and survival. However, serum transaminases had no correlation with liver mean dose and survival, and were rather affected by other local treatments. Compared to the CTCAE, the increase in the CP score of 2 points or more was better correlated with liver failure and overall survival, and it was not affected by other local treatments or tumor progression. We concluded RIHT was better defined by the change in the CP score rather than the CTCAE in patients treated by stereotactic body radiotherapy for HCC.