Breast cancer brain metastases: Molecular subtype, treatment and survival

No clear guidelines exist for management of breast cancer brain metastases (BCBM).

We assessed the relationship between patient and tumor characteristics, treatment, and overall survival (OS).

We conducted a retrospective review of 196 patients who received brain radiation for BCBM between 2009-2013 at Mayo Clinic. Primary tumor characteristics were collected, including simplified molecular subtype. Other characteristics included patient's ECOG, number of brain lesions at BCBM diagnosis, and treatment received, including neurosurgery, whole-brain radiation therapy (WBRT), and stereotactic radiosurgery (SRS). The primary endpoint was OS from time of BCBM diagnosis.

Single-variable analysis revealed patients with HER2+ breast cancer had improved OS (HR = 0.6, p = 0.008). Compared to patients with 1-3 brain lesions, the risk of death in patients with leptomeningeal disease was 2.5-fold higher (p = 0.003). Worsening ECOG status was associated with worsening OS. Patients who received SRS and WBRT had improved OS (HR = 0.37, p < 0.001) compared to patients receiving WBRT alone.

Patients with the best OS had an ECOG of 0, HER2+ disease, and 1-3 brain lesions. The best OS was associated with the combination of neurosurgery and radiation therapy. A comprehensive treatment plan including neurosurgical evaluation and radiation therapy should be considered for patients with BCBM.