The researchers are doing this study is to find out whether treating brain metastasis with SRS after 3 months of therapy with osimertinib is better than treating with osimertinib alone in people with NSCLC. The researchers will also look at how the study intervention impacts participants' quality of life. The researchers will measure quality of life by having participants complete questionnaires.
Age ≥ 18 years
Non-small cell lung cancer (NSCLC) with somatic activating mutation in EGFR diagnosis, confirmed at enrolling institution
At least one intact brain metastasis at baseline prior to TKI therapy initiation, visible on MRI brain with contrast (but without a minimum diameter requirement)
Either TKI-naïve or started TKI ≤ 3-months prior (with documented start date and available imaging prior to TKI start)
Unable to undergo contrast-enhanced MRI brain
Prior brain-directed radiotherapy
Evidence of leptomeningeal disease on MRI total spine and/or lumbar puncture cytology. The latter are not mandated by protocol but are rather at the discretion of the treating medical team as clinically indicated.
Neurologic symptoms or presence of a lesion in the brainstem, motor strip, or other eloquent brain area that is felt to warrant immediate intervention with SRS