Brain metastases in breast cancer: prognostic factors and management

The purpose of this retrospective study was to analyze the overall survival of patients with brain metastases due to breast cancer and to identify prognostic factors that affect clinical outcome.

Of the 7,872 breast cancer patients histologically diagnosed with breast cancer between January 1990 and July 2006 at the Asan Medical Center, 198 patients with solitary or multiple brain metastases were included in this retrospective study. Central nervous system (CNS) lesions were diagnosed by computed tomography (CT) or magnetic resonance imaging (MRI). Patients with leptomeningeal or dural metastases without co-existent parenchymal metastatic lesions were excluded in this study. We reviewed the medical records and pathologic data of these 198 patients to characterize the clinical features and outcomes.

The median age of the patients at the diagnosis of brain metastases was 45 years (range 26-78 years). Fifty-five patients (28%) had a single brain metastasis, whereas 143 (72%) had more than two metastases. A total of 157 (79.2%) patients received whole-brain radiation therapy (WBRT). A total of 7 (3.6%) patients underwent resection of solitary brain metastases, 22 (11%) patients underwent gamma-knife surgery, three patients underwent intrathecal chemotherapy (1.5%) and 9 (4.6%) patients received no treatment. The overall median survival time was 5.6 months (95% confidence interval (CI), 4.7-6.5 months) and 23.1% of the patients survived for more than 1 year. The median overall survival time was 5.4 months for patients treated with WBRT, 14.9 months for patients treated with surgery or gamma-knife surgery only, and 2.1 months for patients who received no treatment (P < 0.001). Multivariate analysis demonstrated that Eastern Cooperative Oncology Group (ECOG) performance status (relative risk (RR) = 0.704, 95% CI 0.482-1.028, P = 0.069), number of brain metastases (RR = 0.682, 95% CI 0.459-1.014, P = 0.058), treatment modalities (RR = 1.686, 95% CI 1.022-2.781, P = 0.041), and systemic chemotherapy after brain metastases (RR = 1.871, 95% CI 1.353-2.586, P < 0.001) were independent factors associated with survival.

Although survival of breast cancer patients with brain metastases was generally short, the performance status, number of brain metastases, treatment modalities and systemic chemotherapy after brain metastases were significantly associated with survival. Patients with single-brain metastasis and good performance status deserve aggressive treatment. The characteristics of initial primary breast lesions did not affect survival after brain metastasis.