Radiation-induced liver disease in three-dimensional conformal radiation therapy for primary liver carcinoma: The risk factors and hepatic radiation tolerance

Purpose: To identify risk factors relevant to radiation-induced liver disease (RILD) and to determine the hepatic tolerance to radiation. Methods and Materials: The data of 109 primary liver carcinomas (PLC) treated with hypofractionated three-dimensional conformal radiation therapy (3D-CRT) were analyzed. Seventeen patients were diagnosed with RILD and 13 of 17 died of it. Results: The risk factors for RILD were late T stage, large gross tumor volume, presence of portal vein thrombosis, association with Child-Pugh Grade B cirrhosis, and acute hepatic toxicity. Multivariate analyses demonstrated that the severity of hepatic cirrhosis was a unique independent predictor. For Child-Pugh Grade A patients, the hepatic radiation tolerance was as follows: ( 1 ) Mean dose to normal liver (MDTNL) of 23 Gy was tolerable. ( 2 ) For cumulative dose–volume histogram, the tolerable volume percentages would be less than: V 5 of 86%, V 10 of 68%, V 15 of 59%, V 20 of 49%, V 25 of 35%, V 30 of 28%, V 35 of 25%, and V 40 of 20%. ( 3 ) Tolerable MDTNL could be estimated by MDTNL (Gy) = −1.686 + 0.023 * normal liver volume (cm 3 ). Conclusion: The predominant risk factor for RILD was the severity of hepatic cirrhosis. The hepatic tolerance to radiation could be estimated by dosimetric parameters.