General Information About Childhood Astrocytomas
Key Points for This Section
- Childhood astrocytoma is a disease in which benign (noncancer) or malignant (cancer) cells form in the tissues of the brain.
- Astrocytomas may be benign (not cancer) or malignant (cancer).
- The central nervous system controls many important body functions.
- The cause of most childhood brain tumors is not known.
- The signs and symptoms of astrocytomas are not the same in every child.
- Tests that examine the brain and spinal cord are used to detect (find) childhood astrocytomas.
- Childhood astrocytomas are usually diagnosed and removed in surgery.
- Certain factors affect prognosis (chance of recovery) and treatment options.
Astrocytomas are tumors that start in star-shaped brain cells called astrocytes. An astrocyte is a type of glial cell. Glial cells hold nerve cells in place, bring food and oxygen to them, and help protect them from disease, such as infection. Gliomas are tumors that form from glial cells. An astrocytoma is a type of glioma.
This summary is about the treatment of tumors that begin in astrocytes in the brain (primary brain tumors). Metastatic brain tumors are formed by cancer cells that begin in other parts of the body and spread to the brain. Treatment of metastatic brain tumors is not discussed here.
Brain tumors can occur in both children and adults. However, treatment for children may be different than treatment for adults. See the following PDQ summaries for more information about other types of brain tumors in children and adults:
Benign brain tumors grow and press on nearby areas of the brain. They rarely spread into other tissues. Malignant brain tumors are likely to grow quickly and spread into other brain tissue. When a tumor grows into or presses on an area of the brain, it may stop that part of the brain from working the way it should. Both benign and malignant brain tumors can cause signs and symptoms and almost all need treatment.
Astrocytomas are most common in these parts of the central nervous system (CNS):
- Cerebrum : The largest part of the brain, at the top of the head. The cerebrum controls thinking, learning, problem-solving, speech, emotions, reading, writing, and voluntary movement.
- Cerebellum : The lower, back part of the brain (near the middle of the back of the head). The cerebellum controls movement, balance, and posture.
- Brain stem : The part that connects the brain to the spinal cord, in the lowest part of the brain (just above the back of the neck). The brain stem controls breathing, heart rate, and the nerves and muscles used in seeing, hearing, walking, talking, and eating.
- Hypothalamus : The area in the middle of the base of the brain that controls body temperature, hunger, and thirst.
- Visual pathway: The group of nerves that connect the eye with the brain.
- Spinal cord: The column of nerve tissue that runs from the brain stem down the center of the back. It is covered by three thin layers of tissue called membranes. The spinal cord and membranes are surrounded by the vertebrae (back bones). Spinal cord nerves carry messages between the brain and the rest of the body, such as a message from the brain to cause muscles to move or a message from the skin to the brain to feel touch.
Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk with your child's doctor if you think your child may be at risk. Possible risk factors for astrocytoma include:
- Past radiation therapy to the brain.
- Having certain genetic disorders, such as neurofibromatosis type 1 (NF1) or tuberous sclerosis.
Having NF1 may increase a child's risk of a certain type of tumor called visual pathway glioma. These tumors usually do not cause symptoms. Children with NF1 who develop visual pathway gliomas may not need treatment for the tumor unless signs or symptoms, such as vision problems, appear or the tumor grows.
Signs and symptoms depend on the following:
- Where the tumor forms in the brain or spinal cord.
- The size of the tumor.
- How fast the tumor grows.
- The child's age and development.
Some tumors do not cause signs or symptoms. Signs and symptoms may be caused by childhood astrocytomas or by other conditions. Check with your child's doctor if your child has any of the following:
- Morning headache or headache that goes away after vomiting.
- Nausea and vomiting.
- Vision, hearing, and speech problems.
- Loss of balance and trouble walking.
- Worsening handwriting or slow speech.
- Weakness or change in feeling on one side of the body.
- Unusual sleepiness.
- More or less energy than usual.
- Change in personality or behavior.
- Weight loss or weight gain for no known reason.
- Increase in the size of the head (in infants).
The following tests and procedures may be used:
- Physical exam and history : An exam of the body to check general signs of health. This includes checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
- Neurological exam : A series of questions and tests to check the brain, spinal cord, and nerve function. The exam checks a person’s mental status, coordination, and ability to walk normally, and how well the muscles, senses, and reflexes work. This may also be called a neuro exam or a neurologic exam.
- Visual field exam: An exam to check a person’s field of vision (the total area in which objects can be seen). This test measures both central vision (how much a person can see when looking straight ahead) and peripheral vision (how much a person can see in all other directions while staring straight ahead). The eyes are tested one at a time. The eye not being tested is covered.
- MRI (magnetic resonance imaging) with gadolinium : A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of the brain and spinal cord. A substance called gadolinium is injected into a vein. The gadolinium collects around the cancer cells so they show up brighter in the picture. This procedure is also called nuclear magnetic resonance imaging (NMRI). Sometimes magnetic resonance spectroscopy (MRS) is done during the same MRI scan to look at the chemical makeup of the brain tissue.
If doctors think there may be an astrocytoma, a biopsy may be done to remove a sample of tissue. For tumors in the brain, a part of the skull is removed and a needle is used to remove tissue. Sometimes, the needle is guided by a computer. A pathologist views the tissue under a microscope to look for cancer cells. If cancer cells are found, the doctor may remove as much tumor as safely possible during the same surgery. Because it can be hard to tell the difference between types of brain tumors, you may want to have your child's tissue sample checked by a pathologist who has experience in diagnosing brain tumors.
The following test may be done on the tissue that was removed:
- Immunohistochemistry : A test that uses antibodies to check for certain antigens in a sample of tissue. The antibody is usually linked to a radioactive substance or a dye that causes the tissue to light up under a microscope. This type of test may be used to tell the difference between different types of cancer. An MIB-1 test is a type of immunohistochemistry that checks tumor tissue for an antigen called MIB-1. This may show how fast a tumor is growing.
Sometimes tumors form in a place that makes them hard to remove. If removing the tumor may cause severe physical, emotional, or learning problems, a biopsy is done and more treatment is given after the biopsy.
Children who have NF1 may not need a biopsy or surgery to remove the tumor.
- Where the astrocytoma formed in the CNS and if it has spread.
- Whether cancer cells remain after surgery.
- The type and grade of astrocytoma.
- Whether the child has NF1.
- Whether there are certain changes in the genes.
- The child’s age.
- Whether the astrocytoma has just been diagnosed or has recurred (come back).
For recurrent astrocytoma, prognosis and treatment depend on how much time passed from the time treatment ended to the time the astrocytoma recurred.