Post-Treatment Performance Status and Prognosis in Patients with Brain Metastases as the First Manifestation of Advanced Non-Small Cell Lung Cancer.

BACKGROUND: Brain metastasis (BM) can substantially affect performance status (PS) and survival in patients with non-small cell lung cancer (NSCLC). We evaluated changes in PS after BM treatment and their association with overall survival (OS) in patients presenting with symptomatic BM as the initial manifestation of NSCLC. METHODS: We retrospectively analyzed patients without a prior history of lung cancer who were newly diagnosed with symptomatic BM between December 2010 and November 2025. We evaluated changes in PS and their association with OS. A 60-day landmark analysis was performed to address potential immortal time bias. RESULTS: Sixty-two patients were included, with a median OS of 16 months. Favorable post-treatment PS was associated with longer OS, whereas pretreatment PS was not. In the 60-day landmark analysis of 54 patients, favorable post-treatment PS and the use of tyrosine kinase inhibitors or immune checkpoint inhibitors, relative to conventional chemotherapy, were associated with longer OS. PS improved by ≥1 grade in 52% of the landmark cohort, and the proportion with PS 0-1 increased from 39% to 69%. Among patients with baseline PS ≥2, younger age and baseline PS of 2 were associated with improvement to PS 0-1. CONCLUSION: Favorable post-treatment PS was associated with longer OS. Reassessment of PS after BM treatment may provide additional prognostic information and inform subsequent treatment decisions.