RT Journal Article SR Electronic T1 What predicts radiation pneumonitis best? Pulmonary injury after curatively intended radiotherapy of early-stage lung cancer JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP PA4846 DO 10.1183/13993003.congress-2016.PA4846 VO 48 IS suppl 60 A1 Berg, Janna A1 Bengtson, May-Bente A1 Brustugun, Odd Terje A1 Helland, Ã…slaug YR 2016 UL http://erj.ersjournals.com/content/48/suppl_60/PA4846.abstract AB Introduction Several studies reports changes in lung function after radiotherapy and evaluate the CT morphological pattern of pulmonary injury.We present preliminary data from our prospective lung cancer study, looking for predictive factors for radiation pneumonitis after curatively intended radiotherapy in patients with inoperable lung cancer stage I-IIIB.Material and methods We have serial measurements from 31 patients, of whom 18 and 13 received stereotactic and fractionated radiotherapy 2 Gyx33, respectively. The patients were followed by several methods (spirometry, total lung capacity, clinical COPD Questionnaire and radiological changes etc.) at baseline, 6 weeks, 3, 6, 9 and 12 months after therapy.Results Five patients in the stereotactic radiotherapy group (27 %) and 5 patients the fractionated group (39%) developed radiation pneumonitis grad 1-4. The lung function was reduced at 3 months follow-up, measured as a significant fall in FVC (p=0.02) and FEV1 (p=0.12) at 6 months.Patients receiving stereotactic radiotherapy reported dyspnoea at 6 months follow-up simultaneously with radiological changes, 1-3 month later than pulmonary functions changes. Patients receiving fractionated radiotherapy, showed reduced lung function and reported dyspnoea already at 6 weeks after therapy, with radiological changes occurring after 1-3 months, 3 months earlier than patients in the stereotactic group.Conclusion The changes in pulmonary function of patients with radiation pneumonitis occur earlier than radiological changes and symptoms. Patients should be followed tightly with both radiology and testing of lung function the first year after treatment.