Brain metastases

Brain metastases are one of the most feared complications of cancer, because even small tumors may cause incapacitating neurologic symptoms. Surgical resection, often the major treatment modality in other cancers, is unavailable for many patients and also can cause neurologic morbidity. Furthermore, slight growth of a brain metastasis can kill patients by compressing normal brain against a nonexpansible skull, herniating the intracranial contents across compartmental precincts. The main contrast to disease in other organs is the inhomogeneity of the brain that leads to focal neurologic deficits often caused by small but seemingly strategically placed metastases. Over a century ago, the eminent physician Gowers wrote: "It is probable that, in most forms of [brain] tumor, arrest of growth now and then occurs, but these are exceptions too few and far between to justify, in any given case, more than the dimmest ray of hope" [1]. Since that time vast improvements in the diagnosis and treatment of brain metastases have led to significant improvements in prognosis. This article reviews the epidemiology, clinical features, treatment, and prognosis of brain metastases from systemic malignancies.