Temporal evolution of breast cancer brain metastases treatments and outcomes

Brain metastases (BMs) are a common complication of advanced breast cancer (BC), and their management has significantly evolved. We evaluated the clinical impact of these changes dividing patients diagnosed with BCBMs at three Institutions according to year of BMs diagnosis: 2000-2007 (group A), 2008-2014 (group B) and 2015-2022 (group C). Stereotactic radiotherapy increased (p < 0.001), and WBRT decreased (p = 0.010) over time. Among HER2+ BC patients, more received anti-HER2 therapy after BM diagnosis in recent years (p < 0.011). Overall survival (OS) did not improve in the entire cohort (p = 0.260); however, OS improved in patients with HR-/HER2+ BC (median OS 8.7, 10.1, 23.7 months in group A, B, C, respectively; p = 0.002). HER2-positivity, not prognostic in group A, became prognostic in group C (p < 0.001). While therapy for patients with BCBMs significantly changed over two decades, an OS improvement was observed only in HR-/HER2+ patients, potentially due to increased availability of anti-HER2 therapies with intracranial activity.