The purpose of this trial is to compare the evolution of patients receiving first line treatment for locally advanced or metastatic lung cancer, taking into account if they were requested or not the EGFR mutation test as part of the diagnosis and treatment strategy. There is no assignment to any particular therapeutic strategy.

Study of cases and controls on diagnosis and treatment strategies in patients with NSCLC with or without EGFR mutations.

Inclusion Criteria:

• Patients with confirmed diagnosis of lung adenocarcinoma, stage IIIb/IV.
• Patients under 1st line treatment against lung adenocarcinoma.

Exclusion Criteria:

• Patients not having the information required by the protocol.

Patients will be recruited from specialized sites; all the participating investigators will be oncologists.