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

• Signed Informed consent.
• Age ≥ 18 years.
• Pre-surgical disease evaluation including brain MRI/CT-scan and total body PET-FDG CT-scan prior to surgery.
• Histologically complete anatomical resection (R0) of stage pIB-IIIA (pTNM 8th edition) NSCLC.
• Presence of a common EGFR mutation (Del19 or L858R).
• Archival tumour tissue FFPE blocks from surgery available for centrally molecular analyses.
• 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.
• Patient who is capable, according to the investigator, of complying with the study's requirements and restrictions.
• Patient followed in the institution on a regular basis (every 3 to 6 months) according to standard recommendations.
• Estimated life expectancy > 3 years.
• 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.
• Male subjects who are sexually active with a woman of childbearing potential are eligible if an efficacious contraception method should be used during the treatment and during the 4 months following the last dose.

Exclusion criteria

• History of cancer, except for the following situations:

Patients with history of cancer for more than 3 years are eligible if they have been treated and considered cured. Patients with history of in situ carcinoma of the cervix or non-melanoma skin carcinoma are eligible.

• Neoadjuvant anti-cancer treatment (osimertinib and/or chemotherapy or other anti-cancer treatment).
• Incompletely resected NSCLC (R1 or R2).
• Any medical condition that would, according to the investigator's judgment, prevent the patient's participation in the clinical study.
• 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.