Prospective study of long-term pulmonary manifestations of mantle irradiation.

Given the high cure rate of patients with Hodgkin's disease, the complications related to therapy take on great significance. Mantle irradiation to the thorax is used in virtually all patients with early stage Hodgkin's disease. Prior studies of patients receiving mantle irradiation demonstrated short-term (up to 24 months) abnormalities of pulmonary function. In the present study, we prospectively studied 13 patients for up to 60 months after irradiation only with serial pulmonary function tests, arterial blood gas tests, diffusing capacity of carbon monoxide, chest radiographs, and ventilation-perfusion scans. No respiratory symptoms attributable to therapy were noted. Frequent radiographic changes (62%) were found consisting of apical fibrosis, paramediastinal fibrosis, or pleural thickening. Two patients developed an asymptomatic spontaneous pneumothorax that resolved with conservative management. Ventilation-perfusion scans often (73%) revealed decreased perfusion to the lung apices with associated ventilatory deficits in one-half of these patients. Patients with intrathoracic disease had decreased lung volumes prior to therapy, and lung volumes did not change following irradiation. Lung mechanics were normal throughout the study. Gas exchange at rest was normal in patients with extrathoracic disease. Patients with intrathoracic disease often presented with an abnormal arterial PO2 and widened alveolar-arterial partial pressure gradient for oxygen. However, these parameters normalized by 9 months after therapy. Despite the frequent development of radiographic and V/Q scan abnormalities in the lung apices, patients tolerated mantle radiotherapy remarkably well. In fact, patients with intrathoracic disease demonstrated improved gas exchange at rest following therapy.