Observational, retrospective cohort study that will include patients diagnosed with NSCLC and ALK rearrangement between January 2015 and December 2020.

Inclusion Criteria:

• Patients older than 18 years;
• Newly diagnosed advanced stage IIIB-IV NSCLC (AJCC 8th edition) or locally advance/distant relapse in the period of January 2015 to December 2020.
• NSCLC with pathological confirmation of ALK rearrangement by immunohistochemistry, fluorescent in situ hybridization (FISH) or next generation sequencing (NGS);
• ECOG 0-4;
• Patients with CNS metastases are also considered eligible, regardless of the initial treatment instituted.

Exclusion Criteria:

- Incomplete medical chart in terms of date of diagnosis, ALK test results and outcomes

Diagnostic patients with NSCLC and ALK rearrangement between January 2015 and December 2020.