This study will use real-world data to assess prevalence of brain metastases in metastatic non-small cell lung cancer (mNSCLC) patients and its impact on associated clinical outcomes.

This retrospective cohort database study will generate real-world evidence describing prevalence of brain metastases at metastatic diagnosis and by line of therapy, patient characteristics, treatment patterns, and clinical outcomes in metastatic non-small cell lung cancer (mNSCLC) patients

Inclusion Criteria:

1. Diagnosis of mNSCLC in study period (01/01/2015-06/30/2023) including newly diagnosed at metastatic stage or progression from advanced stage NSCLC

2. Age 18+ years at the time of diagnosis of mNSCLC

   Additional inclusion criteria for 1st Line of Therapy cohort:

3. Treated with systemic anti-cancer therapy in 1L setting

   Additional inclusion criteria for 2nd Line of Therapy and 3rd Line of Therapy cohorts:

4. Treated with systemic anti-cancer therapy in 2L setting treated with systemic anti-cancer therapy in 3L setting

Exclusion Criteria:

1. Evidence of other primary malignancy in the 365-day baseline period immediately prior to the first mNSCLC diagnosis in the study period
2. Evidence of stereotactic radiosurgery (SRS), stereotactic radiation therapy (SRT), or whole brain radiotherapy (WBRT) in the baseline period

Participants diagnosed with metastatic NSCLC between 2015-2023 treated with systemic therapy.