Abnormalities on chest radiographs following radiation therapy for breast cancer

The aim of this study was to study pulmonary radiological abnormalities with chest radiography following different radiotherapy (RT) techniques for breast cancer with respect to regions and density, and their association with pulmonary complications and reduction in vital capacity (VC). Chest radiographs were performed 5 months following local or loco-regional RT in 167 breast cancer patients. The radiological abnormalities were analysed with a classification system originally proposed by Arriagada and evaluated according to increasing density (0-3) and affected lung regions (apical-lateral, basal-lateral, central-parahilar). The highest-density grades in each region were added together to form scores ranging from 0 to 9. The patients were monitored for RT-induced pulmonary complications. The VC was measured prior to and 5 months following RT. An independent evaluation of 51 patients was performed by a second radiologist to control the reproducibility of the classification system. Increasing scores were associated with loco-regional RT and pulmonary complications (P < 0.001). The mean reduction of VC for patients scoring 0-3 (-30 ml) vs 4-9 (-161 ml) was not statistically significant (P = 0.10). Scores of 4-9 were more frequently observed in older patients (P < 0.001). The independent evaluations by two radiologists revealed good agreement (P < 0.001) and no systematic inter-observer variation. Radiological abnormalities on chest radiographs, scored according to Arriagada, can be used as an objective end point for RT-induced pulmonary side effects in breast cancer.