A Prospective Cohort Study to Evaluate Molecular pRognostic Factors and Resistance Mechanisms to Osimertinib in Adjuvant Treatment of Completely Resected pIB-IIIA Non-small Cell Lung Carcinoma With Common EGFR Mutations (L858R and Del19)

Inclusion Criteria

• •1. Signed Informed consent.
• •2. Age ≥ 18 years.
• •3. Pre-surgical disease evaluation including brain MRI/CT-scan and total body PET-FDG CT-scan prior to surgery.
• •4. Histologically complete anatomical resection (R0) of stage pIB-IIIA (pTNM 8th edition) NSCLC.
• •5. Presence of a common EGFR mutation (Del19 or L858R).
• •6. Archival tumour tissue FFPE blocks from surgery available for centrally molecular analyses.
• •7. Patient eligible to receive osimertinib adjuvant therapy in a 3-year intent to treat decision; patients could receive if necessary adjuvant chemotherapy before starting osimertinib treatment.
• •8. Patient who is capable, according to the investigator, of complying with the study's requirements and restrictions.
• •9. Patient followed in the institution on a regular basis (every 3 to 6 months) according to standard recommendations.
• •10. Estimated life expectancy \> 3 years.
• •11. Woman patients who are of childbearing potential are eligible:
• •* They must have a negative pregnancy test before the first dose of osimertinib.
• •* They must agree to use effective methods of contraception throughout the course of treatment and should be maintained for 2 months after the end of treatment.
• •2. Neoadjuvant anti-cancer treatment (osimertinib and/or chemotherapy or other anti-cancer treatment).
• •3. Incompletely resected NSCLC (R1 or R2).
• •4. Any medical condition that would, according to the investigator's judgment, prevent the patient's participation in the clinical study.
• •5. Active infection (e.g. patients receiving treatment for infection) including hepatitis C virus (HCV) and human immunodeficiency virus (HIV), or active uncontrolled hepatitis B infection except for the situations described in APPENDIX I. Screening for chronic conditions is not required.