1- primary tumors
- Glioblastoma multiforme Astrocytoma Ependymoma Medulloblastoma Oligodendrocytoma
- Acoustic neuroma
- Benign pituitary adenomas
2- Metastatic tumors
Metastatic carcinomas Meningeal carcinomatosis
Until now, we have concentrated on giving an overview of brain tumors, both benign and cancerous, because they have many common characteristics and problems. If the tumor turns out to be cancerous, it will be further classified by its specific cell type. These include:
This is the largest group of primary brain cancers, accounting for about 45 percent of all cancers arising from brain cells. They have been subdivided into several major categories, according to cell type and clinical behavior.
Glioblastoma multiforme accounts for approximately 25 percent of all primary brain tumors and so constitutes more than half of all gliomas. It is considered the most malignant of all brain cancers and steadily infiltrates surrounding tissue. Cancers of this group are graded according to their microscopic appearance from I (least aggressive) to IV (most aggressive). Typical patients with this cancer are middle-aged. Over 30 percent have convulsions which, together with early signs of widespread brain disturbance, are the major symptoms when the patient is first seen by a physician. Surgery is performed as soon as possible, both to relieve symptoms and to make certain that the problem is not potentially curable. Only extremely high-risk patients with evident incurable disease will be advised to forgo surgery.
The cancer cannot be removed entirely, but decompression of the intracranial pressure and reduction of tumor bulk relieve symptoms and increase survival. Postsurgery radiation and chemotherapy, principally with BCNU, have proved useful in some patients. Advances in surgical technique have improved the results for glioblastoma patients, although 5 percent will die within the postoperative period. About 50 percent of patients will live for six to twelve months after surgery. A small number are still functioning at an acceptable level after two years. Bleeding, tumor growth, and increasing intracranial pressure complicate the later stages of disease.