e18529 Background: The role of preoperative pulmonary rehabilitation is unclear. The aim of the study is short-term efficacy of pulmonary rehabilitation in patients with thoracic tumors and borderline abnormal spirometry results before thoracic surgery. Methods: We observed 12 patients (7 women, 5 men) in mean age of 64 (range 46-82) years. Clinical inclusion criteria were: diagnosis of thoracic tumors and reduced values of FEV1 and FVC predicting postoperative complications. Spirometry and 6MWT were chosen for evaluation of lung function and physical performance during rehabilitation. These tests were performed twice during screening phase to eliminate the factors of learning, and were repeated after first and second week of rehabilitation. Pulmonary rehabilitation included two weeks of training on the treadmill with individually selected speed, physiotherapy exercises and breathing training with using of Triflo. Results: The analyses of results of spirometry and 6MWT before and after 2 weeks of pulmonary rehabilitation indicated the significant differences in values of: 1)FEV1 (L): 1,38 ± 0,23 vs 1,61 ± 0,29 (p=0,01) 2) FEV1 (%N): 56,3 ± 13,9 vs 67,8 ± (p=0,007) 3) FVC (L): 2,24 ± 0,37 vs 2,74 ± 0,67 (p=0,03) 4) FVC (%N): 73,5 ± 15,7 vs 91,2 ± 12,7 (p=0,01) 5) 6MWT distance (m): 251 ± 79 vs 310 ± 74 (p=0,003). Although improvement after rehabilitation, 3 patients were disqualified from lobectomy due to unsatisfactory performance status. Another 3 patients experienced complications during perioperative period. Analysis of pulmonary rehabilitation efficacy showed that 6 patients with favourite outcome after thoracic surgery differed significantly in comparing to others. They achieved significantly higher difference in following parameters: 1) FEV1 (L): 0,4 vs 0,06 (p=0,02) 2) FVC (L): 0,91 vs 0,09 (p=0,02) 3) 6MWT distance (m): 93 vs 25 (p=0,016). Conclusions: A two-week pulmonary rehabilitation leads to significant improvement of lung function and physical performance in patients with thoracic tumors and borderline abnormal spirometry results. A clinically significant increase of absolute values of FEV1, FVC and 6MWT distance may indicate a favourite outcome after thoracic surgery.