Optic nerve glioma is a benign tumor that develops from neuroglial cells (auxiliary cells of nervous system that form the sheath for nerve fibers). Glioma grows slowly and very rarely can threaten a child’s life. The main danger of this tumor type is loss of vision, since the tumor can compress various parts of optic nerve and cause the development of its atrophy.
Optic nerve glioma is mainly a childhood disease, since 75% of cases occur in age group under 10 years. In 30% of children with this diagnosis, an additional hereditary pathology is diagnosed – neurofibromatosis type 1. Much less commonly, optic glioma can develop in adults.
As the tumor grows, it causes vision problems, even complete blindness, if medical help is not sought promptly. Also, those gliomas that grow in the area of optic chiasm near pituitary gland and hypothalamus of brain may be accompanied by various endocrine symptoms and disorders.
Tumors of optic tract account for 5% of all central nervous system neoplasms in children. Treatment plan development depends on several factors: child’s age, visual impairment and endocrine symptoms presence, neurofibromatosis type 1 status, tumor location and size. Experts may recommend both observation and active tactics with complex treatment (surgery, chemotherapy, radiation therapy).
Specialists at Pediatric Hematology Oncology Department of TAMC have unique and extensive experience in managing patients with optic nerve gliomas. Each case of child’s disease is considered individually by a team of specialists (oncologist, ophthalmologist, neurologist, neurosurgeon and other highly specialized doctors, if necessary). Treatment plan is developed taking into account modern treatment protocols and individual characteristics of each child and his disease.
Causes of optic nerve glioma
Unfortunately, the exact causes of optic nerve glioma development have not been established today. It is known that there is a connection between the development of this type of benign tumor and such a hereditary disease as neurofibromatosis type 1 (Recklinghausen disease). If glioma affects optic nerve within orbit (eye socket), it is called intraorbital and refers to ophthalmology.
If glioma affects the visual pathways of the cranial part, it is called intracranial and is most often treated by neurosurgeons.
Symptoms of optic nerve glioma in children
For a long time, optic nerve glioma is asymptomatic. The first signs of the disease are vision problems; as a rule, visual acuity decreases.
The clinical picture depends on tumor location, which part of the visual pathway is affected, whether there is concomitant damage to pituitary gland and hypothalamus with endocrine manifestations, and child’s age.
With intraorbital glioma, child’s visual acuity decreases and exophthalmos (protrusion of eyeball from orbit) appears on affected side. Changes progress slowly because glioma grows gradually, so they are not immediately noticed. As exophthalmos progresses, patient experiences recurrent keratitis, conjunctivitis, and corneal ulcers.
If specific treatment is not started, optic disc begins to suffer, swelling and atrophy of optic nerve develop, which is accompanied by irreversible blindness. This process takes on average 1.5-2 years.
With intracranial glioma, exophthalmos is absent, the disease begins with visual disturbances (decreased visual acuity and optic nerve atrophy development). If tumor compresses or grows into pituitary gland or hypothalamus area, specific endocrine disorders develop.
Modern diagnostics methods of optic nerve glioma
A feature of diagnostics in Pediatric Oncology Department of TAMC is its speed and complexity. All necessary examinations can be completed within 3-5 working days in one place.
Diagnostics of optic nerve glioma must, in addition to consultation with a leading oncologist, include consultation and a detailed examination by a pediatric neurologist and a pediatric ophthalmologist. If a child has endocrine symptoms, contact a pediatric endocrinologist.
To detect a tumor, assess its size and spread, modern medical imaging methods are used: magnetic resonance and/or computed tomography (MRI, CT).
A biopsy is usually not performed. But if, based on data from all of the above examinations, specialist is not sure of diagnosis correctness, then a biopsy may be prescribed, followed by a pathomorphological study of a tissue sample in the best pathohistological laboratories in Israel.
Prognosis for optic nerve glioma in children
The prognosis for optic nerve glioma in children is favorable. 10-year survival is achieved in more than 90% of cases. When treated with radiation therapy (without surgery), vision can be preserved in 81% of children. If treatment program includes surgery, radiation, and chemotherapy in various combinations, vision can be preserved in 90% of cases.
The prognosis of the disease is influenced by the following factors:
- Child’s age at the time of diagnosis.
- Histological type of tumor and its degree of malignancy (gliomas are usually benign neoplasms).
- Glioma location and size. Is it possible to completely remove the tumor surgically? The child has a genetic disease – neurofibromatosis type 1.
Early diagnosis of optic nerve glioma helps to preserve vision and eye health in almost 100% of cases. The faster the pressure on anatomical structures of visual analyzer can be reduced, the higher the likelihood of vision restoration. Therefore, do not hesitate to contact specialists.
Modern treatment of optic nerve glioma in children
Depending on clinical situation, one of two tactics can be chosen for optic nerve glioma in a child: observation tactics and active tactics.
In first case, specialists simply monitor disease development – regular examinations and thorough diagnostics once every six months. If there are no symptoms of disease progression, observation is continued.
If child’s vision deteriorates or there are other signs of disease progression, active tactics are chosen.
Glioma surgical removal is the most preferred treatment for this disease. Complete tumor removal will completely cure the child and preserve his vision. However, technically these are very complicated surgical interventions that require extensive experience and skills of surgeon. TAMC uses stereotactic surgery to remove these brain tumors. Pediatric Oncologyb Department is equipped with hybrid operating rooms, in which surgeries to remove intracranial gliomas are carried out under CT or MRI control (a unique MR Linac installation).
If glioma cannot be completely removed during surgery, doctors use a complex treatment method, that is, they combine surgery with chemotherapy and/or radiation.
Polychemotherapy courses are used for inoperable glioma in young children (up to 3 years), since radiation therapy is contraindicated for them due to development of serious side effects. Most often, for optic nerve gliomas, a combination of following drugs is used: vincristine and carboplatin or TPCV chemotherapy protocol (6-thioguanine, procarbazine, lomustine and vincristine).
Radiation therapy is effective against optic nerve gliomas, but unfortunately has long-term side effects. TAMC uses a special innovative type of radiation for glioma – fractionated stereotactic radiation therapy (FSRT). Compared to standard external beam radiation therapy methods, FRST does not have a serious negative impact on child’s future physical and intellectual development.
Today, application of targeted therapy in treatment of optic nerve gliomas is being actively studied. Targeted drugs act purposefully, that is, they affect certain points of tumor cells, while not affecting other healthy cells of the body, which is associated with much fewer side effects compared to classical chemotherapy. MEK protein inhibitors (trametinib and selumetinib) and BRAF V600E inhibitors (vemurafenib and dabrafenib) are currently being actively studied. All our patients can become participants in such studies absolutely free of charge. For some children, this is the only chance to preserve their vision and continue to live a full, healthy life.
