Biological subtypes and survival outcomes in breast cancer patients with brain metastases (study of the Anatolian Society of Medical Oncology).

ABSTRACT

BACKGROUND: The aim of this study is to determine the relationship between the survival outcomes and biological subtype in breast cancer patients with brain metastases. METHODS: We retrospectively evaluated clinical data from 422 breast cancer patients with brain metastases between 2001 and 2011 from referral centers in Turkey. The study population was divided into four biological subtypes according to their hormone receptor status and HER2 expression. RESULTS: Systemic treatment prolonged median overall survival (OS) after brain metastases in the entire group (14 vs. 3.2 months, p < 0.001). It also prolonged median OS after brain metastases in the triple negative (7.5 vs. 1.6 months, p = 0.010) and luminal A (14.3 vs. 7.1 months, p = 0.003) subgroups. The median OS for untreated patients, chemotherapy and/or hormonal therapy receiving patients, and chemotherapy and/or hormonal therapy plus targeted therapy receivers was 2, 5.8, and 17.7 months, respectively (p < 0.001), in the HER2-overexpressing subgroup. In the luminal B subgroup, it was 3.7, 5.3, and 15.4 months, respectively (p = 0.003). CONCLUSIONS: The use of systemic therapy improves OS after brain metastases in all biological subgroups. Targeted therapies also improve OS after brain metastases in HER2-positive patients. The combined use of targeted therapies and lapatinib are superior to single use and trastuzumab, respectively, in these patients.