Pulmonary Effects of Radiation Therapy

Abstract

The cellular effects of irradiating the lungs are related to the histologic and clinical sequelae. The occurrence and severity of damage are semiquantitatively related to the volume of lung irradiated and the dose rate of irradiation. Radiation therapy is widely used for the treatment of malignant disease. The clinical syndrome occurs in up to about 10% of patients and consists of an acute transient phase, radiation pneumonitis, usually occurring 6-12 wk after radiation therapy. This is followed by clinical remission except in the most severe cases and gradual radiologic progression to the stage of radiation fibrosis over the next 6-12 mo. Concommittant chemotherapy, repeat courses of radiation and steroid withdrawal are exacerbating factors. Characteristic changes in pulmonary function and radiographic appearance are described, and management is reviewed.