Changes in Pulmonary Function Following Image-Guided Stereotactic Lung Radiotherapy

The goal of this study was to present the changes in pulmonary function after SBRT in 127 patients with clinical stage I NSCLC or a single lung metastasis. These patients were either too high risk for an operation or preferred a non-operative treatment approach. PFTs were measured at several time points including within 10 weeks of starting SBRT and then 6 weeks, 3 months, 6 months, 9 months, 1 year and 2 years after treatment (median follow-up was 25 months). At 12 months, there were significant decreases in TLC (-3.6%), FVC (-5.7%), FVC % predicted (-4.6%), FEV1 (-4.1%), and corrected DLCO (-5.2%) compared to baseline. At 24 months, there were significant decreases in FVC (-8.9%), and FEV1 (-7.6%) compared to baseline. When compared to surgical series, the reductions in lung function appear later and are smaller.