Eligibility criteria:

• Completely resected (R0), histologically confirmed NSCLC with pathological T1-T3 category and pathological proof of N1 or N2 disease
• Adequate pre-surgical disease assessment (chest CT and upper abdominal CT – mandatory; mediastinoscopy or PET mandatory if clinical N2 is suspected on chest CT; other examinations according to signs and symptoms to exclude metastatic disease)
• Adequate lymph node sampling
• Randomization between 14 and 42 days after surgery
• Adequate post-surgical recovery
• Age > 18 years
• WHO Performance Status 0 or 1
• Adequate liver and renal function (ALT < 1.5 ULN, bilirubin within normal limits, creatinine < 1.5 ULN) and adequate haematology (haemoglobin >11g/dL, WBC>2.000/L, PLT>100.000/L)
• Written informed consent
• No previous treatment with chemotherapy
• No histological diagnosis of SCLC or mixed NSCLC/SCLC type
• No apparent involvement of mediastinal lymph nodes at preoperative staging (cN2)
• No evidence of metastatic disease (M1)
• Stable medical conditions (e.g. no myocardial infarction within 12 months, unstable angina, active psychiatric disorder)
• No active infection
• No history of malignancy other than basal-cell skin cancer or in situ cervical cancer
• No history of severe renal or liver insufficiency
• No history of a recent gastrointestinal bleeding or active ulcer disease or extensive gastro-intestinal surgery that may affect the drug absorption
• No participation in any investigational study within 30 days prior to enrollment
• No pregnancy or lactation or inadequate contraception
• No known hypersensitivity to celecoxib, other COX-2 inhibitors or aspirin (aspirin triad)
• No chronic use of NSAID’s (selective inhibitors of COX-2 and non- selective COX inhibitors), acetylsalicylic acid (aspirin) nor oral steroids >14 days during one month prior to surgery nor anticipated chronic use of the above drugs during the study