The patients from 12 centers were included into the study. pN2 patients received PORT, pN1 patients did not. PORT was 3D-planned and consisted in 54-56 Gy in 27-28 fractions. One month after surgery, all patients completed EORTC QLQ C-30 questionnaires and had pulmonary function tests (PFT); cardiopulmonary symptoms were assessed by modified LENT-SOM score. Two years after, all patients free of disease repeated the same examinations. Changes in QLQ, LENT-SOM score and the results of PFT were compared for patients receiving and not PORT.

Inclusion Criteria:

• complete resection by lobectomy, bi-lobectomy or pneumonectomy of NSCLC,
• pN1 or pN2 disease,
• signed informed consent for participation in the study,
• Karnofsky Performance Status (KPS) higher than 70%.

Exclusion Criteria:

• presence of distant metastases,
• N2 diagnosed before surgery in imaging and/or mediastinoscopy,
• previous radiotherapy to the chest,
• no or inadequate mediastinal nodal dissection ,
• FEV1 after surgery lower than 1.0 liter,
• any active infectious process (including fistula formation) in the chest

It was assessed that during planned 3 years of accrual approximately 360 stage II patients treated with surgery alone and approximately 240 stage III patients treated with surgery and postoperative radiotherapy (PORT) would enter the study.The higher number of inclusions of pN1 was planned, because of expected higher percentage of cancer related deaths within two years in pN2 patients.

Patients with pN1 disease were followed in the thoracic surgery center and had no PORT. Patients with pN2 disease were referred to PORT.