Long-term cardiac mortality following radiation therapy for Hodgkin's disease: analysis with the relative seriality model

Purpose: (a) To assess the increased risk of death due to ischemic heart di sease (IHD) in a group of patients treated for Hodgkin's disease (HD) with radiation therapy (RT) as the primary treatment. (b) To quantify the dose r esponse of IHD using a biophysical model. Materials and methods: Patient material consisted of 157 patients diagnosed for HD between 1972 and 1985 who received RT as the primary treatment at R adiumhemmet, Karolinska Hospital. The general population formed the control group. The RT treatments were reconstructed based on the individual treatm ent data and simulator films. Individual clinical and dosimetrical data wer e analyzed with the relative seriality model. The material was also analyze d grouping the material according to dose-volume constraints. Results: Of the 157 patients, 13 (8.3%) died due to IHD. The standardized m ortality ratio (SMR) was 5.0 (95% CI, 2.7-8.6). Analysis of dose-volume his tograms (DVH) showed an increasing risk with increasing dose to a larger vo lume fraction. The observed individual clinical complication data could not be modeled unambiguously. The group analysis resulted in the dose-response parameters: D-50 = 71 Gy, gamma = 0.96 and s = 1.0. Conclusions: A significantly increased risk of death due to IHD following R T for HD was found. The risk was found to increase with higher dose and lar ger volume fraction irradiated. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.