The extent or spread of cancer is usually described as stages. There is no standard staging system for brain tumors. Brain tumors that begin in the brain may spread to other parts of the brain and spinal cord, but they rarely spread to other parts of the body. Treatment of brain tumors is based on the type of cell in which the tumor began, where the tumor formed in the central nervous system, the amount of cancer left after surgery, and the grade of the tumor. Treatment of brain tumors that have spread to the brain from other parts of the body is based on the number of tumors in the brain.
After the tumor is removed in surgery, some of the