Pericarditis and myocardial infarctions after Hodgkin's disease therapy

From 1971 to 1984, 499 patients with all stages of Hodgkin's disease received mediastinal irradiation at the Institut Gustave-Roussy by 25 MV photons from a linear accelerator. Thirty-five pericarditis (10-year cumulative incidence rate of 9.5%) and 13 myocardial infarctions (MI) (10-year cumulative incidence rate of 3.9%) were observed. In contrast, no cases were diagnosed in a parallel series of 138 Hodgkin's disease patients treated without mediastinal irradiation during the same period of time (p less than 0.005 for pericarditis, p less than 0.05 for MI). By multivariate analysis, the role of total radiation dose given to the mediastinum and that of fraction size were evaluated, adjusting for age, sex, mediastinal involvement, and type of chemotherapy. The pericarditis risk was significantly increased with total dose greater than or equal to 41 Gy (relative risk (RR) = 3.25, p = 0.006) and with dose per fraction greater than or equal to 3.0 Gy (RR = 2.0, p = 0.06). The myocardial infarction risk was not found to be related to total dose nor to fraction size in this series, possibly because of the small number of events.