About Brain Cancer
Brain tissue is composed of nerve cells — gray and white matter — and supporting tissue made up of glial cells. There are an estimated 100,000,000,000 nerve cells (or neurons) in the human brain, yet they account for only five to 10 percent of all cells in the nervous system. Much more common are the glial cells that support, protect and provide nutrition for nerve cells. Glial cells also help form the blood-brain barrier, which controls the entry of foreign substances, including medications, into the brain.
The brain has the consistency of jelly and is marked, on its surface, with heavy folds and ridges. Weighing about three pounds, it lies snugly within the skull, covered by three layers of membranes called the meninges.
The brain is the control center of the body, allowing us to recognize, think about and respond to external stimuli.
Brain cancer is the growth of abnormal cells in the brain or skull. A brain tumor may be either cancerous (malignant) or noncancerous (benign). Both types of tumors are serious because either one can compress and damage brain tissue. Both can also cause identical symptoms.
Brain cancer is either a primary cancer, meaning that it originates within the brain, or is a secondary cancer, meaning that it has spread (metastasized) to the brain from another site in the body, such as a lung or breast. When tumors spread to the brain they contain cancer cells from the original tumor.
A cancer that originates in the brain rarely spreads to other parts of the body, but it may spread to other parts of the brain. The cause of most brain tumors is not known. An estimated 1.4 percent of all cancers in children and adults are cancers of the brain and spinal cord.
Even a small tumor can cause symptoms, such as headaches, seizures or bleeding. Most tumors, however, cause no symptoms until they have grown large enough to compress brain tissue, which can then also cause the following:
- Personality change
- Weakness or paralysis in an arm or leg
- Difficulty speaking
- Difficulty swallowing