Symptomatic radiation-induced pericarditis in Hodgkin's disease.

This is a retrospective review of 193 evaluable patients treated with radiation therapy to the mediastinum for Stages I, II and III-A Hodgkin's disease. Eligible patients were those receiving 3000 rad or more to the mediastinum and no chemotherapy prior to the radiation. During the study period, 13 patients developed symptomatic pericarditis. The interval post treatment to the development of symptoms was six to 34 months. The incidence of pericarditis was studied as a function of: (1) the dose of radiation at a depth of 2 cm, 5 cm and the midplane of the mediastinum; (2) the ratio of anterior to posterior weighting of dose; (3) the presence or absence of intrathoracic tumor; (4) the size of the tumor when present; and (5) the fraction of the heart exposed to the radiation beam. There was a significant increase in the incidence of pericarditis with an increased dose of radiation at 2 cm, 5 cm and midplane depths and also with the presence of a large intrathoracic tumor. A reduction in mediastinal dose is recommended.