At a Glance
- An adult brain tumor is a disease in which abnormal tumor cells form in the tissues of the brain.
- Brain tumors account for 85 to 90 percent of all primary central nervous system (CNS) tumors.
- Risk factors for brain tumors include ionizing radiation from high dose x-rays (such as radiation therapy from a large machine aimed at the head) and and other sources can cause cell damage that leads to a tumor.
- The most common brain tumor symptoms include headaches (usually worse in the morning); nausea and vomiting; changes in speech, vision, or hearing; problems balancing or walking; changes in mood, personality, or ability to concentrate; problems with memory; muscle jerking or twitching (seizures or convulsions); numbness or tingling in the arms or legs.
- Primary brain tumors can be benign or malignant.
About Brain Cancer
Worldwide, approximately 22,850 new cases of brain and other CNS tumors will be diagnosed in 2015, with an estimated mortality of 15,320. In general, the incidence of primary brain tumors is higher in whites than in blacks, and mortality is higher in males than in females.
Anatomy of brain
The brain is a soft, spongy mass of tissue. It is protected by the bones of the skull, three thin layers of tissue (meninges), watery fluid (cerebrospinal fluid) that flows through spaces between the meninges and through spaces (ventricles) within the brain.
The brain directs the things we choose to do (like walking and talking) and the things our body does without thinking (like breathing). The brain is also in charge of our senses (sight, hearing, touch, taste, and smell), memory, emotions, and personality.
A network of nerves carries messages back and forth between the brain and the rest of the body. Some nerves go directly from the brain to the eyes, ears, and other parts of the head. Other nerves run through the spinal cord to connect the brain with the other parts of the body.
Within the brain and spinal cord, glial cells surround nerve cells and hold them in place.
The three major parts of the brain control different activities:
- Cerebrum: The cerebrum uses information from our senses to tell us what is going on around us and tells our body how to respond. It controls reading, thinking, learning, speech, and emotions. The cerebrum is divided into the left and right cerebral hemispheres.
- The right hemisphere controls the muscles on the left side of the body.
- The left hemisphere controls the muscles on the right side of the body.
- Cerebellum: The cerebellum controls balance for walking and standing, and other complex actions.
- Brain stem: The brain stem connects the brain with the spinal cord. It controls breathing, body temperature, blood pressure, and other basic body functions.
Tumor Grades and Types
When most normal cells grow old or get damaged, they die, and new cells take their place. Sometimes, this process goes wrong. New cells form when the body doesn’t need them, and old or damaged cells don’t die as they should. The buildup of extra cells often forms a mass of tissue called a growth or tumor.
Primary brain tumors can be benign or malignant.
Benign brain tumors do not contain cancer cells:
- Usually, benign tumors can be removed, and they seldom grow back.
- Benign brain tumors usually have an obvious border or edge. Cells from benign tumors rarely invade tissues around them. They don’t spread to other parts of the body. However, benign tumors can press on sensitive areas of the brain and cause serious health problems.
- Unlike benign tumors in most other parts of the body, benign brain tumors are sometimes life threatening.
- Benign brain tumors may become malignant.
Malignant Brain Tumors (also called brain cancer) contain cancer cells:
- Malignant brain tumors are generally more serious and often are a threat to life.
- They are likely to grow rapidly and crowd or invade the nearby healthy brain tissue.
- Cancer cells may break away from malignant brain tumors and spread to other parts of the brain or to the spinal cord. They rarely spread to other parts of the body.
Doctors group brain tumors by grade. The grade of a tumor refers to the way the cells look under a microscope:
- Grade I: The tissue is benign. The cells look nearly like normal brain cells, and they grow slowly.
- Grade II: The tissue is malignant. The cells look less like normal cells than do the cells in a Grade I tumor.
- Grade III: The malignant tissue has cells that look very different from normal cells. The abnormal cells are actively growing (anaplastic).
- Grade IV: The malignant tissue has cells that look most abnormal and tend to grow quickly.
Cells from low-grade tumors (grades I and II) look more normal and generally grow more slowly than cells from high-grade tumors (grades III and IV). Over time, a low-grade tumor may become a high-grade tumor. However, the change to a high-grade tumor happens more often among adults than children.