Diagnosis and management of central nervous system metastases from breast cancer

The brain, cranial nerves, leptomeninges, spinal cord, and eye compose the central nervous system (CNS) and are at risk for the development of metastases from breast cancer. Such metastases are diagnosed on the basis of clinical suspicion and substantiated by neuroimaging, resection when indicated, and sampling of cerebrospinal fluid when leptomeningeal metastasis (LM) is suspected. Treatment is aimed at palliation of symptoms and preservation of neurologic function. Historically, conventional radiation therapy has been the mainstay of palliative treatment for brain, cranial nerve, spinal cord, and ocular metastases. However, additional treatment options for brain metastases have been brought about by technological advances in surgery to resect brain metastases, and stereotactic radiosurgery (SRS) to focally irradiate metastases, both of which have been substantiated by data from randomized trials. Ongoing research is aimed at refining criteria to select which patients with brain metastases should undergo surgery and SRS and how these focal therapies should be optimally integrated with whole-brain radiotherapy. Therapy for LM must carefully balance the potential risks and perceived benefits associated with CNS-directed therapies. Despite advances in neuroimaging, surgery, and radiation therapy, novel treatments are needed to improve the effectiveness of treatments for CNS metastases, especially LM, while reducing attendant neurotoxicity.