Cancer Management Chapter 23: Primary and metastatic brain tumors

Intracranial neoplasms can arise from any of the structures or cell types present in the cranial vault, including the brain, meninges, pituitary gland, skull, and even residual embryonic tissue. The overall annual incidence of primary brain tumors in the United States is 14 cases per 100,000 population. The most common primary brain tumors are meningiomas, representing 27% of all primary brain tumors, and glioblastomas, representing 23% of all primary brain tumors; many of these tumors are clinically aggressive and high grade. Primary brain tumors are the most common of the solid tumors in children and the second most frequent cause of cancer death after leukemia in children. Brain metastases occur in approximately 15% of cancer patients as a result of hematogenous dissemination of systemic cancer, and the incidence may be rising due to better control of systemic disease. Lung and breast cancers are the most common solid tumors that metastasize to the central nervous system (CNS). Melanoma and testicular and renal carcinomas have the greatest propensity to metastasize to the brain, but their relative rarity explains the low incidence of these neoplasms in large series of patients with brain metastases. Patients with brain metastases from nonpulmonary primaries have a 70% incidence of lung metastases. Although many physicians presume that all brain metastases are multiple, in fact, half are single and many are potentially amenable to focal therapies. Epidemiology