| "Do not go where the path may lead, go instead where there is no path - and leave a trail." ~ Ralph Waldo Emerson ~ |
| So What Is Optic Nerve Glioma? |
| ORPHANS OF THE CANCER STORM |
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| Optic Nerve Glioma, which primarily arise from cells called astrocytes, are usually slow-growing, low-grade tumours of a type called juvenile pilocytic astrocytoma (JPA), but can sometimes present in a more aggressive form, such as anaplastic astrocytoma and primative neuroectodermal tumour (PNET). ONGs may involve only one optic nerve/tract (unilateral) or both (bilateral). They may also affect the junction of the optic nerves called the "optic chiasm", and an area of the brain called the hypothalamus.. Most gliomas of the optic nerve are discovered before the age of 10 years and there is a high incidence of this tumour in children who have neurofibromatosis type 1 (NF-1)1. Surgery is rarely a treatment possibility for gliomas of the optic nerve because of difficulties in opening up the nerve sheath without causing significant damage. This course of treatment is not recommended for tumours presenting with chiasmatic/hypothalamic involvement because these stuctures lie deep within the brain and thus present high risks to sight and vital functions. However, surgery may be considered for children with profound visual loss or when there is significant bulging of eyeballs (proptosis). In most cases where tumours affect intra-orbital portions of the optic nerve, the affected eye is removed (enucleation). The treatment of optic gliomas with radiotherapy remains controversial. Many radiation oncologists advocate deferring radiation in patients with no symptoms or in those with lesser visual disturbance until there are signs of disease progression2. Chemotherapy is administered in such cases in an effort to defer the use of radiotherapy3. However, some oncologists recommend that radiotherapy be administered early in the course of the disease to minimise the risk of visual deterioration4. Proton beam therapy may have an advantage over photon beam therapy (standard external beam radiotherapy) because of the beam characteristics which increase normal tissue protection when it is planned, set up, and delivered properly5. Optic nerve gliomas often remain stable for long periods of time, and many doctors thus favour a wait-and-watch-closely approach rather than embarking on agressive therapy. In general, tumours of the optic nerve (intracranial as well as intraorbital) have an excellent prognosis following complete surgical excision and/or irradiation6; 7. _____ References. Please note these links go only to abstracts of the articles. 1) http://www.nfinc.org/text/plex.html Dr Roger Packer - relationship of NF-1 and OG. 2) Jenkin D, Angyalfi S, Becker L, Berry M, Buncic R, Chan H, Doherty M, Drake J, Greenberg M, Hendrick B, et al. Optic glioma in children: surveillance, resection, or irradiation? International Journal of Radiation Oncology Biology Physics 1993 Jan 15;25(2):215-25 3) Rosenstock JG, Packer RJ, Bilaniuk L, Bruce DA, Radcliffe JL, Savino P. Chiasmatic optic glioma treated with chemotherapy. A preliminary report. Journal Neurosurgery 1985 Dec;63(6):862-6 4) Wong JY, Uhl V, Wara WM, Sheline GE. Optic gliomas. A reanalysis of the University of California, San Francisco experience. Cancer 1987 Oct 15;60(8):1847-55 Department of Radiation Oncology, University of California, San Francisco. 5) www.llu.edu/proton 6) Flickinger JC, Torres C, Deutsch M. Management of low-grade gliomas of the optic nerve and chiasm. Cancer 1988 Feb 15;61(4):635-42 Joint Radiation Oncology Center, University of Pittsburgh, PA 15213. 7) Alvord EC Jr, Lofton S. Gliomas of the optic nerve or chiasm. Outcome by patients' age, tumor site, and treatment. Journal of Neurosurgery 1988 Jan;68(1):85-98 Department of Pathology, University of Washington School of Medicine, Seattle. Return to the SONGS home page. |
| Disclaimer This information page has been prepared by an individual who does not have medical training. However its contents have been reviewed by appropriately qualified medical professionals for accuracy and quality. This page is intended for information purposes only and should not be used as a guide to diagnosis or treatment. If this information raises any concerns about your child’s condition or care protocol, discuss them with his or her paediatrician, oncologist, or other appropriate medical professional who has knowledge of the case. |