Characterization of Treatments and Disease Course for Women with Breast Cancer Brain Metastases: 5-Year Retrospective Single Institution Experience.

Purpose Around 30% of patients with breast cancer will develop brain metastases (BM). We sought to characterize the disease course, treatments and outcome for our patient cohort. Materials and methods We extracted clinicopathological data from electronic records from January 2015 to December 2020. Results were generated using SPSS statistics v27. Results We identified 98 patients. Median overall survival (OS) from BM diagnosis was 3 months [hormone receptor (HR)+/human epidermal growth factor receptor 2 (HER2)-], 8 months [HR+/HER2+], 7 months [HR-/HER2+] and 2 months [triple negative breast cancer (TNBC)]. Whole brain radiotherapy (WBRT) (n=48, 70%) was most frequently used followed by surgery (n=15, 22%) and stereotactic radiosurgery (n=6, 8%). In patients who received WBRT alone (n=40) the median OS post WBRT was 2.6 months. Conclusion After BM development, half of the patients had systemic therapy and 70% had local therapy, but only the HER2 subgroup had a prolonged OS likely reflecting central nervous system (CNS) activity of anti-HER2 drugs. TNBC patients had the worst prognosis. Although our cohort is small, OS was >1 year for 60% of HER2+ patients who received trastuzumab emtansine after BM development, which is encouraging for antibody drug conjugates and CNS activity. Patients who received WBRT had a higher burden of CNS disease and had an OS of less than 3 months.