Risk factors and survival outcomes in patients with brain metastases from breast cancer.

Development of central nervous system (CNS) metastases in breast cancer (BC) is associated with poor prognosis. The incidence of CNS metastases in metastatic BC is reported to be about 10-16 %, but different subtypes of BC are associated with different risk of developing CNS metastases. We retrospectively analysed the risk of CNS metastases and the outcome in a cohort of 473 patients with metastatic BC. CNS metastases were diagnosed in 15.6 % of patients and median survival from diagnosis of CNS metastases was 7.53 (25th-75th 2.8-18.9) months. The risk of developing CNS metastases was higher in patients with grade 3, hormone receptor negative, HER2-positive, high Ki-67 BC. When compared to luminal A subtype, only HER2-positive BC was associated with increased risk of CNS metastases. Survival from diagnosis of CNS metastases was longer in patients with HER2-positive BC, while it was shorter in patients that did not receive any locoregional treatment, or with extra-CNS disease, or with more than 3 CNS lesions.