Brain metastases are increasingly important causes of morbidity and mortality in breast cancer patients. Whole brain radiotherapy (WBRT) and surgery remains the standard treatment for brain metastases. However, the median overall survival after brain and leptomeningeal metastasis were only 8.5 months and 16 weeks respectively There is lack of standard treatment for brain metastasis progression post WBRT. Chemotherapy was considered mostly poor for treatment response because of the blood brain barrier. However, this has been questioned because tumor can disrupt the normal function of blood brain barrier. For example, etoposide and cisplatin had been used for treatment for breast cancer patients with brain metastasis. The overall response rate of central nervous system (CNS) was 39 %, disease control rate was 60%, although the median overall survival was 31 weeks only. The role of targeted therapies is actively being assessed. Recently, a phase II study of lapatinib in patients with brain metastases from HER2-positive breast cancer showed that CNS objective response rates were 6% to lapatinib monotherapy and 20% to lapatinib plus capecitabine. Although the result is promising, the treatment population is limited in the HER2 overexpression breast cancer.~Bevacizumab, an anti-angiogenic agent, has been approved to combine with several chemotherapy agents in breast, lung and colon cancer. It was once considered contraindicated in patients with brain metastases due to the possibility of intracranial bleeding. However, two studies involving the use of bevacizumab for treating brain metastatic tumors of non-squamous or peripherally located squamous lung cancer showed no report of brain hemorrhage. In addition, bevacizumab has been approved to treat primary brain aggressive tumors recently.~In the institution, the investigators treated three breast cancer patients with multiple brain metastases using bevacizumab plus etoposide and cisplatin (B-EP). All of them have been treated for at least two lines of chemotherapy before brain metastases occurred. All of them received WBRT for brain metastases and one of them also received craniotomy with brain tumor resection plus local stereotactic radiosurgery. The follow up magnetic resonance imaging (MRI) had revealed recurrent metastatic brain tumors in one patients, and recurrence of leptomeningeal metastasis in another two patients. One patient who has multiple brain parenchyma metastases showed objective response on MRI after two cycle of B-EP treatment, and remained progression free for more than 5 months. The other two patients with leptomeningeal metastasis had intrathecal and intraventricular (via Ommaya reservoir) methotrexate treatment for more than eight doses. They were near stupor before B-EP treatment. Both had best clinical response of full recovery of consciousness and absence of cancer cells in cerebrospinal fluid. One survived eight months after the diagnosis leptomeningeal metastasis, and the other two were still alive six months after the diagnosis of leptomeningeal metastasis .~Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) has been used in various studies for evaluation of anti-angiogenic condition. In breast cancer, DCE-MRI has been used as an early predictive marker for response. Glioblastoma patients have also been evaluated with DCE-MRI to determine reduction of vessel permeability after bevacizumab treatment.~Proton magnetic resonance spectroscopy (1H-MRS) has been used to different benign brain tumors from malignant ones. The utilization of 1H-MRS, especially in human brain tumors, coupled to both routine MRI and functional MRI techniques provides greater information concerning tumor grading and extension and characterization of the normal surrounding tissue than what is possible with any other imaging technique alone. To analyze proton spectroscopy before and after bevacizumab may give us further information about the mechanism of B-EP on CNS metastasis.~Therefore, the investigators propose to conduct a phase II clinical trial to test the efficacy of B-EP regimen in breast cancer patients with CNS metastasis along with brain DCE-MRI to demonstrate the antiangiogenesis efficacy.
The main purpose of this study is to investigate the efficacy of bevacizumab, etoposide and cisplatin in treating breast cancer patients with central nervous system metastasis (including brain parenchymal and leptomeningeal metastasis).