Clinical outcomes and breast cancer subtypes in patients with brain metastases.

Background: The principal objective of this study was to assess clinical outcomes by breast cancer subtype in patients with brain metastases.

Methods: Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2) status was evaluated via immunohistochemical staining. Four survival time intervals were compared according to the subtype (ER+/HER2-, HER2+, triple negative (TN)).

Results: 20 (30.3%) of the 66 patients in this study were ER+/HER2-, 20 (30.3%) were HER2+, and 26 (39.4%) were TN. The disease-free survival rates of ER+/HER2-, HER2+, and TN patients were 30.0, 17.0, and 17.9 months, respectively (p = 0.040). The median time intervals from distant metastasis to brain metastasis were 20.6, 19.5, and 9.0 months, respectively (p = 0.012). The times from initial diagnosis to brain metastasis were 52.9, 33.6, and 25.5 months, respectively (p = 0.026). However, the overall survival rates did not differ significantly (p = 0.276).

Conclusions: Patients with TN breast cancer were more likely to develop distant metastasis earlier, and also evidenced poor overall survival. Triple receptor status may be employed as a prognostic marker for breast cancer patients with brain metastases.