Background: The incidence of brain metastases in patients with breast cancer is approximately 10% - 16%, and survival after diagnosis of brain metastases is usually short. This study was designed to evaluate the risk factors associated with brain metastases in advanced breast cancer patients, with a view to help predict patient groups with high risk of brain metastases.
Methods: In total, 295 patients with advanced breast cancer were evaluated. All patients were pathologically confirmed and metastatic lesions were confirmed pathologically or by imaging. All patients were examined at least once every 6 months with head CT or MRI. Patients showing symptoms underwent immediate inspection, and brain metastatic lesions were confirmed by head CT and/or MRI.
Results: At a median follow-up of 12 months from the occurrence of metastases, brain metastases had occurred in 49 patients (16.6%). In our univariate analysis, variables significantly related to increased risk of brain metastases were hormone receptor-negative tumors, epidermal growth factor receptor 2 (HER2)-positive tumors, and multiple distant metastases. Patients with dominant tumor sites in soft tissue, or defined as Luminal A subtype, tended to have a lower risk of brain metastases than patients with visceral metastases, Luminal B subtype, triple-negative subtype or HER2-enriched subtype tumors.
Conclusions: Our results strongly suggest that factors such as Luminal B, triple-negative, and HER2-enriched subtypes are high risk factors for brain metastases. These data, therefore, provide pivotal clinical evidence towards a comprehensive understanding of the risk factors of brain metastases in advanced breast cancer patients.