Article

Fractionated radiotherapy for optic nerve sheath meningiomas

Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA 94143-0112, USA.
Journal of Clinical Neuroscience (Impact Factor: 1.32). 06/2012; 19(9):1210-5. DOI: 10.1016/j.jocn.2012.02.010
Source: PubMed

ABSTRACT Optic nerve sheath meningiomas (ONSM) are rare tumors of the meninges that surround the optic nerve as it enters the orbit. If left untreated, these benign tumors lead to progressive compression of the optic nerve and vascular compromise resulting in visual loss. Surgical resection of ONSM is associated with a high morbidity due to injury to the vascular supply of the optic nerve, with up to 94% of patients reporting worsened vision post-operatively. Fractionated radiotherapy is a non-invasive alternative to surgery for the treatment of ONSM that has demonstrated improved outcomes. The reported long-term tumor control rates approach 100%, with greater than 80% vision preservation or improvement after treatment. Recently, improved technology for delivery of radiotherapy, including stereotactic and three-dimensional conformal radiotherapy has emerged. The literature suggests that the modality of radiotherapy does not affect the outcomes as long as conformal targeting with a total dose of 50 Gy to 54 Gy and a fractional dose of less than 2.0 Gy is used. Radiosurgery is not generally used for ONSM due to the high toxicity to the optic nerve when high-dose single fraction radiation is given. Therefore, conformal fractionated radiotherapy appears to be the most effective treatment for ONSM, and should be used as a primary therapy unless there is a specific indication for surgical intervention.

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    ABSTRACT: With respect to its characteristic pattern of growth from the orbit into the intracranial space toward the chiasm, patients with optic nerve sheath meningiomas (ONSM) are threatened to loose function of both optic nerves. Fortunately, in less than 5% both optic nerves are involved initially. Hence, prevention of vision of the contralateral eye is the foremost aim of any therapy. Performing pre-chiasmatic transection might offer a further treatment option to avoid further tumor growth toward the chiasm. In this retrospective study 12 patients with ONSM and blindness of the affected eye were included. The surgical approach was performed either from pterional intradural or as a combined approach from pterional extra- and intradural. Without any exceptions, vision of the contralateral eye could be preserved and did not show any deterioration after surgery or during the follow-up time of 50.6 months. Furthermore in 58.3% of patients gross total tumor resection could be achieved. During follow up observation in 67% of patients no further tumor progress or recurrences could be observed. 4 patients, however, showed delayed tumor progress or recurrences that were treated by radiotherapy. Pre-chiasmatic transection of the optic nerve might offer a surgical treatment option to control tumor growth and to preserve vision of the contralateral eye.
    Clinical neurology and neurosurgery 09/2013; 115(12). DOI:10.1016/j.clineuro.2013.08.027 · 1.25 Impact Factor

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