Epidemiology of central nervous system metastases.

Brain metastases are overwhelmingly the most common type of brain tumor, out numbering primary brain tumors in incidence by more than four-to-one. They are associated with poor prognosis both from a length-of-life as well as a quality-of-life standpoint. Once the brain metastasis is detected, without treatment, most patients die within months, either from widespread systemic disease, or due to the brain metastasis itself. The complications of brain metastases are also devastating. Patients can suffer from seizures, weakness or paralysis, language and communication deficits, as well as cognitive decline. These complications negatively impact on quality of life through effects on functional independence, impairment of capacity to participate in activities and relationships, as well as distortion of individual personality and identity. At the same time, there are great financial burdens associated with both the care and treatment of patients with brain metastases. Early detection of brain metastases in cancer patients is critical for limiting these complications, minimizing these burdens and improving the outlook regarding both survival and quality of life. Understanding the epidemiology of brain metastases can lead to the development of new strategies for the early identification and successful treatment of these patients.