Breast cancer subtypes and outcomes of central nervous system metastases

Central nervous system (CNS) metastases are detected in up to one third of patients with advanced breast cancer, but their incidence and outcomes by breast cancer subtypes are not precisely documented. Herein, we retrospectively analyzed clinicopathologic data of 259 breast cancer patients with CNS metastases to evaluate the association between breast cancer subtypes and CNS metastasis. The patient groups were classified according to their hormone receptor status and HER-2 expression. Median follow-up time among the patients was 42 months and median survival after CNS metastasis detection was 7.8 months. In HER-2 overexpressing group, median time period between the diagnosis of breast cancer and the detection of CNS metastasis (15.9 months) was significantly shorter compared to the other groups (p = 0.01). The triple negative group had the shortest median survival time after CNS metastasis (6.6 months), although statistically not significant (p = 0.3). In multivariate Cox regression analyses, having solitary CNS metastasis (HR 0.4, 95% CI; 0.2-0.7, p = 0.004), and receiving chemotherapy after CNS metastasis (HR 0.4, 95% CI; 0.287-0.772, p = 0.003) were independent prognostic factors for increasing survival after CNS metastasis. In conclusion, new and effective treatment strategies are required for breast carcinoma patients with brain metastasis considering the positive effect of the treatment on survival.