Analysis of Hepatitis B Virus Reactivation After Radiotherapy in Patients With Hepatocellular Carcinoma Using the Lyman NTCP Model.

Purpose: To analyze the correlation of hepatitis B virus reactivation with patient-related and treatment-related dose-volume factors and to describe the feasibility of hepatitis B virus reactivation analyzed by a normal tissue complication probability model for patients with hepatocellular carcinoma treated with radiotherapy. Materials and Methods: Ninety patients with hepatitis B virus-related hepatocellular carcinoma treated with radiotherapy were enrolled in this retrospective study and were followed from June 2009 to December 2015. Of the 90 patients, 78 had received conventional fractionation radiotherapy to a mean dose of 39.6 to 50.4 Gy and 12 patients were scheduled to receive hypofractionation. The physical doses were converted into 2 Gy equivalents for analysis. The parameters, TD50 (1), n, and m, of the Lyman-Kutcher-Burman normal tissue complication probability model were derived using maximum likelihood estimation. Bootstrap and leave-one-out were employed to against model overfitting and improve the model stability. Results: Radiation-induced liver diseases were 17.8%, hepatitis B virus reactivation was 22.2%, and hepatitis B virus reactivation-induced hepatitis was 21.1%, respectively. In multivariate analysis, the V-5Gy was associated with hepatitis B virus reactivation; TD50 (1), m, and n were 32.3, 0.55, and 0.71 Gy, respectively, for hepatitis B virus reactivation. Bootstrap and leave-one-out results showed that the hepatitis B virus parameter fits were extremely robust. Conclusion: A Lyman-Kutcher-Burman normal tissue complication probability model has been established to predict hepatitis B virus reactivation for patients with hepatocellular carcinoma who received radiotherapy.