PRIMARY AND METASTATIC TUMORS OF THE NERVOUS SYSTEM: INTRODUCTION

Malignant primary tumors of the central nervous system (CNS) occur in ~16,500 individuals and account for an estimated 13,000 deaths in the United States annually, a mortality rate of 6 per 100,000. The age-adjusted incidence appears to be about the same worldwide. An approximately equal number of benign tumors of the CNS are diagnosed, with a much lower mortality rate. Glial tumors account for 50–60% of primary brain tumors, meningiomas for 25%, schwannomas for 10%, and other CNS tumors for the remainder.

Brain and vertebral metastases from systemic cancer are far more prevalent than primary CNS tumors. About 15% of patients who die of cancer (80,000 individuals each year in the United States) have symptomatic brain metastases; an additional 5% suffer spinal cord involvement. Brain and spinal metastases therefore pose a major problem in the management of systemic cancer.