What is childhood visual pathway glioma?
Childhood visual pathway glioma is a type of brain tumor in which cancer (malignant) cells begin to grow in the tissues of the brain. The brain controls memory and learning, the senses (hearing, sight, smell, taste, and touch), and emotion. It also controls other parts of the body, including muscles, organs, and blood vessels. Other than leukemia or lymphoma, brain tumors are the most common type of cancer that occurs in children.
Gliomas are a type of astrocytoma, tumors that start in brain cells called astrocytes. A visual pathway glioma occurs along the nerve that sends messages from the eye to the brain (the optic nerve). Visual pathway gliomas are visual pathway tumors. They may grow rapidly or slowly, depending on the grade of the tumor.
This summary covers tumors that start in the brain (primary brain tumors). Often cancer found in the brain has started somewhere else in the body and has spread (metastasized) to the brain.
Like most cancer, childhood brain tumor is best treated when it is found (diagnosed) early. If your child has symptoms, the doctor may order a computed tomographic (CT) scan, a special x-ray that uses a computer to make a picture of your child’s brain. A magnetic resonance imaging (MRI) scan, which uses magnetic waves to make a picture of your child’s brain, may also be done.
Often, surgery is required to see whether there is a brain tumor and to tell what type of tumor it is. The doctor may cut out a piece of tissue from the brain and look at it under a microscope. This is called a biopsy.
There are many types of brain tumors in children and the chance of recovery (prognosis) depends on the type of tumor, where it is located within the brain, and your child’s age and general health.
Once childhood visual pathway glioma is found, more tests will be done to find out the type of tumor. If a biopsy specimen is taken, the cancer cells will be looked at carefully under a microscope to see how different they are from the normal cells. This will determine the histologic grade of the tumor. Your child’s doctor needs to know the type and grade of tumor in order to plan treatment.
There is no staging for childhood visual pathway glioma. The treatment depends on whether or not your child has received treatment.
Untreated childhood visual pathway glioma
Untreated childhood visual pathway glioma means that no treatment has been given except to treat symptoms.
Treatment Option Overview
There are treatments for all children with visual pathway glioma. Three kinds of treatment are used:
- Surgery (taking out the cancer in an operation).
- Radiation therapy (using high-dose x-rays to kill cancer cells).
- Chemotherapy (using drugs to kill cancer cells).
Experienced doctors working together can often give the best treatment for children with visual pathway glioma. Your child’s treatment will often be coordinated by a pediatric oncologist, a doctor who specializes in cancer in children. The pediatric oncologist may refer you to other doctors, such as a pediatric neurosurgeon (a specialist in childhood brain surgery), a pediatric neurologist, a psychologist, a radiation oncologist, and other doctors who specialize in the type of treatment your child requires.
Surgery is one treatment for visual pathway glioma. Depending on where the cancer is and the type of cancer, your child’s doctor may remove as much of the tumor as possible. If the tumor cannot be totally removed, radiation therapy and chemotherapy may also be given. If the cancer is in a place where it cannot be removed, surgery may be limited to a biopsy of the cancer.
Radiation therapy uses high-energy x-rays to kill cancer cells and shrink tumors. Radiation therapy for childhood brain tumors usually comes from a machine outside the body (external radiation therapy). Because radiation therapy can affect growth and brain development, clinical trials are testing ways to decrease or delay radiation therapy, especially for younger children. These include internal radiation therapy, in which radiation is put into the brain through thin plastic tubes, and hyperfractionated radiation therapy, in which radiation therapy is given in several small doses per day instead of all at once. Conformal radiation therapy uses a computer to create a 3-D picture of the tumor and the radiation beams are shaped to fit the tumor; this helps to keep the radiation away from healthy tissue as much as possible.
Chemotherapy uses drugs to kill cancer cells. Chemotherapy may be taken by pill, or it may be put into the body by a needle in a vein or muscle. Chemotherapy is called a systemic treatment because the drug enters the bloodstream, travels through the body, and can kill cancer cells throughout the body. Chemotherapy is being studied to delay the use of radiation therapy in some patients. Clinical trials are studying different chemotherapy drugs for visual pathway gliomas.
Untreated Childhood Visual Pathway Glioma
Your child’s treatment may be one of the following:
- For patients without symptoms or progression, observation without treatment.
- Radiation therapy.
- Clinical trials evaluating chemotherapy to shrink the tumor and delay radiation therapy.
Recurrent Childhood Visual Pathway Glioma
Treatment for recurrent disease depends on the type of tumor, whether the tumor comes back in the same place or in another part of the brain, and the treatment that was given before.
If possible, the tumor may be removed during surgery. Radiation therapy may be given, especially if it was not given before. Chemotherapy may be used, and clinical trials are evaluating new chemotherapy drugs. You may wish to consider having your child treated with new methods on a clinical trial.
Source: National Cancer Institute