Inclusion of Incidental Radiation Dose to the Cardiac Atria and Ventricles Does Not Improve the Prediction of Radiation Pneumonitis in Advanced-Stage Non-Small Cell Lung Cancer Patients Treated With Intensity Modulated Radiation Therapy

Purpose: To evaluate whether inclusion of incidental radiation dose to the cardiac atria and ventricles improves the prediction of grade >= 3 radiation pneumonitis (RP) in advanced-stage non-small cell lung cancer (AS-NSCLC) patients treated with intensity modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT).Methods and Materials: Using a bootstrap modeling approach, clinical parameters and doseevolume histogram (DVH) parameters of lungs and heart (assessing atria and ventricles separately and combined) were evaluated for RP prediction in 188 AS-NSCLC patients.Results: After a median follow-up of 18.4 months, 26 patients (13.8%) developed RP. Only the median mean lung dose (MLD) differed between groups (15.3 Gy vs 13.7 Gy for the RP and non-RP group, respectively; P=.004). The MLD showed the highest Spearman correlation coefficient (Rs) for RP (Rs = 0.21; P= 3 RP, whereas the heart DVH parameters were seldom included in the model.Conclusion: Incidental dose to the cardiac atria and ventricles did not improve RP risk prediction in our cohort of 188 AS-NSCLC patients treated with IMRT or VMAT. (C) 2017 Elsevier Inc. All rights reserved.