|
My Child Has:
|
|
Optic Pathway Glioma
|
|
|
|
|
|
An optic pathway glioma is a tumor arising from a specific type of glial cell (supportive tissue of the brain) known as an astrocyte.
Astrocytes make up the supportive network of the brain. Optic pathway gliomas are astrocytomas that arise in or around the optic pathway, i.e., the optic nerve, the optic chiasm or the optic radiations.
The hormone center of the brain, essential for the body's endocrine function (such as hormone production, salt and water balance, appetite and sleep centers) is located in close proximity to the visual pathway system. This hormone center can be affected by a glioma of the optic pathway system.
Optic pathway gliomas account for 5 percent of all childhood brain tumors. The majority of patients (75 percent) with optic pathway gliomas are less that 10 years old; most children are less than age 5 at the time of diagnosis. Males and females are equally affected.
|
|
|
|
|
|
Children with neurofibromatosis type I are at increased risk of developing optic pathway gliomas. NF-I is present in 70 percent of children with a glioma isolated to the optic nerve, and in 15-20 percent of children with a glioma of the optic chiasm or optic radiations.
|
|
|
|
|
|
Due to the relative slow growth rate of optic pathway gliomas, children with these tumors tend to have symptoms that have been occurring for many months. Each child may experience symptoms differently, however, common symptoms may include:
|
|
|
- infants: abnormal head movements (head tilt), abnormal eye movements or head bobbing
- toddlers and older children: visual loss, abnormal eye movements and/or developmental delay
- children: because the optic pathway system lies in close proximity to the hormone center of the brain, some children will have abnormal growth, weight gain/loss and/or endocrine dysfunction (issues related to hormone production, salt and water balance)
|
|
The symptoms of a brain tumor may resemble other conditions or medical problems. Always consult your child's physician for a diagnosis.
|
|
|
|
|
|
Diagnostic procedures for an optic pathway glioma may include:
|
|
|
- physical examination - the child may demonstrate decreased vision, a loss of peripheral vision and/or abnormal eye movements
- computerized tomography scan (also called a CT or CAT scan) - a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. CT scans are more detailed than general x-rays. For optic pathway glioma, a CT scan of the brain is usually done.
- magnetic resonance imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body. For optic pathway glioma, an MRI of the brain is usually done.
- examination and visual testing - an ophthalmologist will exam the child and conduct comprehensive visual testing. This information will be used in conjunction with MRI findings to make an accurate diagnosis.
|
|
Surgical biopsy and tumor removal are not routinely performed due to the risk of damaging the delicate optic pathway system.
|
|
|
|
|
|
Specific treatment for an optic pathway glioma will be determined by your child's physician based on:
|
|
|
- your child's age, overall health, and medical history
- type, location, and size of the tumor
- extent of the disease
- your child's tolerance for specific medications, procedures, or therapies
- how your child's doctors expect the disease to progress
- your opinion or preference
|
|
Treatment for an optic pathway glioma is recommended when there is vision loss/endocrine dysfunction. Surgery is not a reasonable treatment option because of the risk of damaging the very delicate structures of the vision center during an operation.
Treatment may include (alone or in combination):
|
|
|
- chemotherapy - a drug treatment that works by interfering with the cancer cell's ability to grow or reproduce. Different groups of chemotherapy drugs work in different ways to fight cancer cells and shrink tumors. Often, a combination of chemotherapy drugs is used to fight a specific cancer. Certain chemotherapy drugs may be given in a specific order depending on the type of cancer it is being used to treat.
A number of combinations of chemotherapy drugs, such as vincristine with carboplatin and vincristine with CCNU, procarbazine and thioguanine, are currently being utilized to stabilize and, in some cases, to shrink the size of the glioma.
While chemotherapy can be quite effective in treating certain cancers, the agents do not differentiate normal healthy cells from cancer cells. Because of this, there can be many adverse side effects during treatment. Being able to anticipate these side effects can help the care team, parents, and child prepare, and, in some cases, prevent these symptoms from occurring, if possible.
Chemotherapy is systemic treatment, meaning it is introduced to the bloodstream and travels throughout the body to kill cancer cells. Chemotherapy can be given:
- as an injection into the muscle or fat tissue
- intravenously (directly to the bloodstream; also called IV)
- intrathecally - chemotherapy given directly into the spinal column with a needle
- radiation therapy - radiation therapy to the bed of the tumor can be very effective in halting the growth of these tumors. There is data to suggest 10-year survival rates of 70- 90 percent in children that have received radiation therapy. Radiation therapy, however, often affects normal hormone function and may affect learning, so it is often avoided in the initial treatment. Radiation therapy uses high-energy rays (radiation) from a specialized machine to damage or kill cancer cells and shrink tumors.
|
|
|
|
Children with optic pathway gliomas may have side effects related to the tumor itself and its treatment. Symptoms at the time of diagnosis related to visual deficits and/or endocrine dysfunction may improve slightly with either chemotherapy or radiation therapy. The goal of treatment is to prevent further visual and/or endocrine deterioration.
Common side effects related to chemotherapy include nausea, vomiting and decreased blood counts (i.e. anemia). Anti-emetics (anti-nausea) medications are administered with the chemotherapy to control symptoms of nausea and vomiting. Occasionally, children receiving chemotherapy will require transfusion of red blood cells and/or platelets to replace these cells since chemotherapy temporarily decreases the body's ability to produce red blood cells and platelets. White blood cells are also reduced with chemotherapy, however, these cells are not transfused. Occasionally, children will receive a medication to assist the body in producing white blood cells.
Radiation therapy may cause swelling related to tissue inflammation. This inflammation may lead to symptoms of headache or deterioration of visual/endocrine function. These symptoms, if significant, may be treated with the oral medication dexamethasone.
|
|
|
|
|
|
Unilateral disease (a glioma of the optic pathway affecting one eye) is associated with a high rate of cure. Gliomas affecting more central structures (optic chiasm) or bilateral disease is associated with a lower cure rate (approximately 50 percent). Prognosis is not affected by the presence or absence of neurofibromatosis.
|
|
|
|
|
|
The recommended treatment for progressive or recurrent optic pathway glioma is radiation therapy. Dana-Farber Cancer Institute is one of nine institutes in the nation belonging to the Pediatric Brain Tumor Consortium. The consortium is dedicated to the development of new and innovative treatments for children with progressive/recurrent brain tumors not responsive to standard therapies. Children with progressive/recurrent optic pathway gliomas would be eligible for a number of experimental therapies available through the consortium.
|
|
|
|
|
|
Children's Hospital and Dana-Farber Cancer Institute are conducting numerous research studies that will help clinicians better understand and treat optic pathway glioma. For more information on current research, see the Brain Tumor Program.
|
|
|
