Definition
Radiation pneumonitis is a common toxicity that occurs in patients undergoing radiation therapy for thoracic malignancies and is a known toxicity occurring in patients undergoing radiation therapy for breast malignancies. Radiation pneumonitis can have considerable impact on patient morbidity, including a patient’s quality of life and respiratory function. However, it usually resolves if treated with corticosteroids. It is rarely fatal.
Pathophysiology
Radiation pneumonitis is the inflammation of the lung tissue due to radiation therapy treatment to thoracic and some breast malignancies.
Incidence/prevalence
The incidence of symptomatic radiation pneumonitis for all sites is approximately 7%.r
The incidence rates of ≥ grade 3 radiation pneumonitis toxicity, in patients who have been treated for thoracic malignancies are as follows:
- RT alone 12-28%r
- RT and chemotherapy 62.7% (≥ grade 2)r
The incidence of pneumonitis is not increased by the use of trastuzumab.r
The incidence rates of ≥ grade 2 radiation pneumonitis toxicity, in patients who have been treated for breast cancer are as follows:
- RT alone ≤ 3%
- RT and chemotherapy (paclitaxel) 8-15%
The incidence rates of ≥ grade 2 radiation pneumonitis toxicity, in patients who have been treated for mediastinal lymphoma are as follows:
Onset/duration
Radiation pneumonitis most commonly occurs between 1 and 6 months after treatment.
Risk factors
The dose of radiation is correlated with the incidence of radiation pneumonitis, as is the total lung volume irradiated, the location of the tumour, the use of chemotherapy (particularly taxanes), pulmonary dysfunction prior to RT and patient age ≥ 70.r