The pulmonary effects of thoracic irradiation

Radiation-induced pulmonary injury is common following treatment for a variety of tumors in and around the thorax. While symptomatic injury is unusual, subclinical injury identified by formal pulmonary function tests and/or radiographs is very common. In this article, the radiologic, symptomatic, and physiologic pulmonary effects of whole and partial thoracic irradiation are summarized from the animal and human data available. The risk of developing significant lung injury appears to be most dependent upon the radiation dose and volume of lung irradiated. Additional studies are needed to develop algorithms to predict the physiologic consequences of a proposed radiation treatment program such that reasonable risk-benefit assessments can be made. This may lead to improvements in the therapeutic ratios that facilitate dose escalation and improve local tumor control and cure rates.