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Also called: optic nerve glioma, optic glioma, chiasmatic glioma, optic pathway tumor
An optic pathway glioma (OPG) is a brain tumor that grows on or near the optic nerve. The optic nerve sends messages from the eye to the brain. Optic pathway gliomas in children are usually low-grade tumors that grow slowly.
As the tumor grows, pressure on the optic nerve can cause vision problems. OPGs can also form near the pituitary gland and hypothalamus. Depending on the location, the tumor may affect endocrine function and hormone production.
OPGs make up 5% of all pediatric central nervous system (CNS) tumors. They are most common in young children and children with neurofibromatosis type 1 (NF1).
Treatment for an OPG depends on the child’s age, vision, NF1 status, and tumor location. Treatments may include surgery, chemotherapy, radiation therapy, and targeted therapy. Treatment is complex because the doctors want to avoid harming vision and endocrine function. Doctors may watch patients over time to see how their disease progresses.
Symptoms of an OPG depend on:
OPG signs and symptoms may include:
Most OPGs occur in children under age 10. These tumors are closely linked to neurofibromatosis type 1 (NF1). About 15% of children with NF1 may develop an OPG. It is important for children with NF1 to have regular eye exams.
Children with NF1 may have slow-growing tumors that can be followed with observation.
Doctors use several tests to diagnose optic pathway gliomas.
The doctor may do an eye exam to check visual function. This includes:
Your child may have a neurological exam to measure brain function. This exam tests:
Other tests may include:
Most OPGs in children are low grade. The cells of a low-grade tumor:
Rarely, OPGs in children may be high grade. High-grade tumors:
There is no single treatment plan for OPG. Because these are usually low-grade tumors, preserving vision is a main concern. Treatment options include observation, surgery, chemotherapy, radiation, and targeted therapy.
Therapies depend on:
Doctors monitor patients using eye exams and regular MRI scans.
If the disease worsens, the patient may have more vision problems, the tumor may grow larger, or the disease may spread.
Surgery may be used to remove as much of the tumor as possible. But surgery alone may not provide a cure. In some cases, surgery is not possible due to the tumor’s location. Risks of surgery include worsening vision or harming nearby structures, including the hypothalamus (a part of the brain).
Chemotherapy is often used to treat OPGs. It is used in younger patients to delay or avoid radiation therapy. It may also be used when surgery is not a good option or surgical tumor removal is not complete. Not all tumors respond to chemotherapy.
Hearing loss may be a side effect of chemotherapy. Your care team will consider this risk when planning treatments. Patients with OPGs may have vision problems, so avoiding hearing loss is important.
No single chemotherapy plan is used for all OPGs. The medical team will figure out the best plan based on your child’s needs. The plan will depend on factors such as:
Some chemotherapy drugs used to treat OPG include vincristine, carboplatin, vinblastine, lomustine, and temozolomide.
Targeted therapies work by acting on, or targeting, specific features of tumor cells. In some tumors, there are changes in the genes and proteins that control tumor cell growth and division. Scientists are testing drugs to see if they can block the signals that cause certain types of cancer cells to grow. Your child’s care team may suggest targeted therapy as a treatment option if it could help treat your child’s disease.
Radiation therapy may be used for older children depending on the type of tumor and its location. In OPG, radiation therapy is the most effective treatment and helps preserve vision. But there is a risk of late effects, especially for younger patients.
Learn more about clinical trials.
The long-term survival rate for childhood OPG is high (above 90% in the United States). But treatment and management of these tumors is complex. Vision problems are common in survivors. Depending on the tumor location, endocrine function may also be affected.
A pediatric cancer care team will need to plan treatments. They will balance cure and quality of life. Every case is different. Ask your care provider for information about your child’s treatment and prognosis.
Prognosis depends on such factors as:
Early diagnosis helps preserve vision and eye health.
Doctors use imaging tests and eye exams to monitor patients long-term. Follow-up care may include specialty areas such as rehabilitation, neurology, and endocrinology.
Eye health is important for survivors of OPGs. Your child should visit an ophthalmologist at least once a year as part of routine health care. Many survivors have lifelong vision problems, and vision assistance may be needed. Low-vision specialists and school accommodations can help children adapt to vision loss. Protective eyeglasses can help prevent eye injury.
Reviewed: May 2023