Brain cancer constitutes such a small proportion of all cancers that statistical overviews usually lump it in a category with all nervous system cancers. The American Cancer Society projects that 16,500 Americans will be diagnosed this year with nervous system cancers and that 13,000 will die. This figure represents about 2 percent of all cancer deaths in the United States. Count all brain tumors, and the numbers change markedly. The American Brain Tumor Association estimates that 35,239 Americans will be diagnosed this year with primary brain tumors, an incidence rate of 12.8 per 100,000 people.
Children especially are vulnerable.
Brain tumors are the second leading cause of cancer-related deaths in people younger than 20. Only leukemia kills more. No one knows what causes brain cancer.