Optic nerve glioma medical therapy
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Medical Therapy
Treatment of optic nerve glioma depend on clinical context, as well as on location of the tumor at presentation. If it is isolated to one optic nerve, and does not extend to the chiasm, then resection is curative (albeit with loss of vision in that eye). If the tumour extends to the chiasm or more posteriorly then curative resection is not possible, with resection reserved for treatment of mass effects (proposis, intracranial mass effect). Treatment of optic nerve glioma varies with general health of the person and the size of the tumor. The goals of the treatment is to improve vision, relieve symptoms, and cure the disorder. The most common treatments for optic nerve glioma are:
- Observation
- Chemotherapy
- Hormone replacement therapy
- Radiation therapy
Observation
Observation as a treatment modality is used, particularly in patients with good vision on the involved side. At regular intervals, follow-up examinations, and appropriate radiographic studies, preferably MRI, must be performed. Many patients if regularly followed up maintain good vision and never require a surgery.
Chemotherapy
- Chemotherapy is used in children to delay radiation therapy, and to reduce the severity of radiation therapy induced side-effects.
- Chemotherapy has the ability to cause tumor regression and stabilize the vision.
- Chemotherapy may be useful when the tumor extends into the hypothalamus, as it has an ability to shrink hypothalamic tumors.
- It is useful in diencephalic syndrome as it allows for weight gain.
- Chemotherapy may carry long-term risks of blood-borne cancers.
Combination chemotherapy using vincristine, actinomycin D, bevacizumab, etoposide, and other agents has also been reported to be effective in patients with progressive hypothalamic/chiasmal gliomas. Chemotherapy alone very rarely cures low-grade gliomas. Mostly, chemotherapy can stop the progression of optic nerve gliomas. But if the tumor is resistant to chemotherapy, radiation is an option.
Radiation
- Radiation therapy is used if the tumor is resistant to chemotherapy
- Radiation therapy is considered if the tumor is unresectable (optic tract or chiasmal lesions), and if neurological symptoms progress.
- Radiation therapy can be done before surgery to shrink the tumor before removing it or after surgery to kill the remaining cancer cells. If chiasmal and optic tract involvement is extensive and if there is growth of the tumor within the chiasm, postoperative radiation of the chiasm and optic tract may be considered.
- Where the tumor is larger and surgery is not possible, radiation therapy may be recommended. In slow growing tumor, radiation therapy may be delayed.
- Corticosteroids may be prescribed if symptoms return or to reduce swelling and inflammation caused during radiation therapy.
Complications of radiation therapy
- Endocrinopathy
- Dementia
- Radionecrosis of the medial temporal lobe
- Leukoencephalopathy
- Developmental and neurocognitive problems
- Vasculopathy
- Middle cerebral artery thrombosis
- Moyamoya ("puff of smoke")
- Moyamoya disease is characterized by occlusion or stenosis of the internal carotid artery and/or the middle cerebral vessels, or proximal portion of the anterior cerebral vessels, resulting in cerebral infarction.
- NF1 patients with optic pathway glioma are less likely to resond to radiotherapy and they have a higher risk of developing late side-effects of radiation therapy.
Hormone replacement therapy
Lifelong hormone replacement therapy is used if the endocrine systems is affected
Alternative medicine
Alternative medicines to control pain and treatment side effects may be used, alternative medicines include:
- Acupuncture/acupressure
- Therapeutic touch
- Herbal supplements
- Dietary recommendations
- Message