Study of Interest of Personalized Radiotherapy Dose Redistribution in Patients With Stage III NSCLC

Inclusion Criteria: * Male or female patients, * Age over 18 years and below 75-year-old, * Good general condition: WHO performance status ≤ 1, * Histological evidence of non-small cell lung cancer, * Measureable tumour according to RECIST 1.1 evaluation criteria, * Mediastinoscopy or endobronchial ultrasound to prove the histological stage N2/N3, * Patient eligible to curative-intent radio-chemotherapy, * Absence of pleural involvement, of pulmonary or extra-thoracic metastatic localisation, * Absence of co-morbidity contra-indicating radio-chemotherapy, * Lung function: FEV1 ≥ 40% of theoretical value and DLCO/VA ≥ 60% of theoretical value and PaO2 ≥ 60 mm Hg, * Tumour FDG uptake higher than mediastinal background noise on baseline PET/CT, * Haematological parameters: * Neutrophil count ≥ 1.5x109/L and platelet count ≥ 100x109/L, * Haemoglobin ≥ 9 g/dL, * Provisional RT plan confirming that the dose objectives (minimal dose of 62.7 Gy (95% of the prescribed dose) in 98% of target volumes and 70.3 Gy for the "boosted" volume at 74 Gy) and constraints (lungs, spinal cord) are met (ICRU83), * Estimated creatinine clearance ≥ 60 mL/min, * Signed informed consent * Affiliated or beneficiary of a social benefit system Exclusion Criteria: * Histology other than non-small cell lung cancer, * Absence of FDG uptake on FDG-PET/CT scan before induction chemotherapy, * Patients for whom curative radiotherapy is not indicated (tumour extension, metastases, general condition, co-morbidities), * Significant interstitial disease on CT scan, * Previous neoplastic disease of less than 5 years duration or progressive (without basal cell carcinoma of the skin, in situ carcinoma of the cervix), * Previous thoracic radiotherapy, * Patient enrolled in another therapeutic trial, * Pregnant women or women of child-bearing potential or breast feeding mothers, * Adult subjects who are under protective custody or guardianship, * Patient unable to comply with the specific obligations of the study (geographic, social or physical reasons), * Uncontrolled diabetes with blood glucose ≥10 mmol/L, * Hypersensitivity to the active substance (FDG) or to any of the excipients, * Patients unable to understand the purpose of the study (language, etc.).