Abnormalities by pulmonary regions studied with computer tomography following local or local-regional radiotherapy for breast cancer

Purpose: To study pulmonary radiological abnormalities with computer tomogr aphy (CT) following different radiotherapy (RT) techniques for breast cance r with respect to regions and density, and their correlation to pulmonary c omplications and reduction in vital capacity (VC). Methods and Materials: CT scans of the lungs were performed prior to and 4 months following RT in 105 breast cancer patients treated with local or loc al-regional RT, The radiological abnormalities were analyzed with a CT-adap ted modification of a classification system originally proposed by Arriagad a, and scored according to increasing density (0-3) and affected lung regio ns (apical-lateral, central-parahilar, basal-lateral), The highest density grade in each region were added together to form scores ranging from 0-9, T he patients were monitored for RT-induced pulmonary complications. VC was m easured prior to and 5 months following RT, Results: Increasing CT scores were correlated with both local-regional RT a nd pulmonary complications (p < 0.001), The mean reduction of VC for patien ts scoring 4-9 (-202 mi) was larger than for patients scoring 0-3 (-2 mi) ( p = 0.035), The effect of confounding factors on the radiological scoring w as tested in the local-regional RT group. Scores of 4-9 were less frequentl y seen in the patients who had received adjuvant chemotherapy prior to RT. The importance of the respective lung regions on the outcome of pulmonary c omplications was tested. Only radiological abnormalities in the central-par ahilar and apical-lateral regions were significantly correlated to pulmonar y complications, Discussion: Radiological abnormalities detected on CT images and scored wit h a modification of Arriagada's classification system can be used as an obj ective endpoint for pulmonary side effects in breast cancer. The described model should, however, be expanded with information about the volume of lun g affected in each region before definite conclusions can be drawn concerni ng each region's relative importance for the development of pulmonary compl ications. The negative association between sequential chemotherapy and radi ological abnormalities should be confirmed in future studies. (C) 1999 Else vier Science Inc.