Predicting Role of Dosimetric Parameters for Nonclassic Radiation-Induced Liver Disease After Helical Tomotherapy in Child-Pugh Class a Primary Liver Carcinoma Patients

Abstract PurposeThis study sought to analyze the predicting role of dosimetric parameters for nonclassic radiation-induced liver disease (RILD) after helical tomotherapy (HT) in Child-Pugh (CP) class A primary liver carcinoma (PLC) patients.Patients and methodsA total number of 71 CP class A PLC patients treated with HT from June 2011 to June 2015 were retrospectively reviewed. Clinical characteristics and dose-volume histogram (DVH) were recorded, and liver functions were followed up for 4 months after radiotherapy.ResultsIn all, 57 patients (80.3%) were male, and 14 (19.7%) were female, with a median age of 53 years. The mean gross tumor volume (GTV) was 226.8 cm3. A median dose of 55.0 Gy was delivered by HT with a median fraction size of 2.6 Gy. Twelve patients (16.9%) were diagnosed with nonclassic RILD. The mean dose to normal liver (MDTNL) and the percentage of total liver volume receiving more than 25 - 35 Gy irradiations (V25 - V35) were related to nonclassic RILD. MDTNL showed the highest AUC (0.705, p=0.026). The optimal cut-off value of MDTNL was 21.3 Gy with a sensitivity, specificity and accuracy of 83.3%, 62.7% and 67.6%, respectively. The tolerable volume percentages for DVH were less than: V25 of 42.3%, V30 of 33.9%, and V35 of 28.3%.ConclusionThis study suggests that MDTNL, V25, V30 and V35 are dosimetric predictors for nonclassic RILD in CP class A PLC patients. MDTNL < 21.3Gy, V25 < 42.3%, V30 < 33.9%, and V35 < 28.3% may be used to optimize HT planning.