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Purpose: Optic nerve sheath meningioma (ONSM) is a rare tumor that almost uniformly leads to visual dysfunction and even blindness without intervention. Because surgical extirpation carries a high risk of postoperative blindness, vision-sparing treatment strategies are desirable. Methods and Materials: We retrospectively reviewed the outcomes of 25 patients (25 optic nerves) with ONSM, treated at a single institution with conformal fractionated radiotherapy by either stereotactic photon or proton radiation. Primary endpoints were local control and visual acuity. Results: The patients presented with symptoms of visual loss (21) or orbital pain (3) or were incidentally diagnosed by imaging (3). The mean age was 44 years, and 64% were female patients. The indication for treatment was the development or progression of symptoms. Of the patients, 13 were treated with photons, 9 were treated with protons, and 3 received a combination of photons and protons. The median dose delivered was 50.4 gray equivalents (range, 45–59.4 gray equivalents). Median follow-up after radiotherapy was 30 months (range, 3–168 months), with 3 patients lost to follow-up. At most recent follow-up, 21 of 22 patients (95%) had improved (14) or stable (7) visual acuity. One patient had worsened visual acuity after initial postirradiation improvement. Of the 22 patients, 20 (95%) had no radiographic progression. Three patients had evidence of asymptomatic, limited retinopathy on ophthalmologic examination, and one had recurrent ONSM 11 years after treatment. Conclusions: Highly conformal, fractionated radiation therapy for symptomatic primary ONSM provides tumor control and improvement in visual function in most cases, with minimal treatment-induced morbidity. Longer follow-up is needed to assess the durability of tumor control and treatment-related late effects. [Copyright &y& Elsevier]

Modern neuroimaging provides excellent characterization of anterior visual pathway gliomas, often obviating the need for biopsy of the tumor. Management remains controversial, but if there is progression, chemotherapy is preferred for young patients. Stereotactically guided conformal radiotherapy and proton beam radiotherapy allow smaller, more precise doses of radiation to be administered and can be considered in older children with progressive disease. A mouse model of NF-1 with optic pathway gliomas has the potential to provide important insights into the development of gliomas as well as serving as a model for their effective treatment. [ABSTRACT FROM AUTHOR]

Focuses on the management of optic nerve sheath meningiomas. Background on the disease; Factors to consider before performing a surgical biopsy for the disease; Complications that arise in using radiation therapy; Benefits of stereotactic radiation therapy to the treatment of the disease.

Highlights • The anterior optic pathway tolerates conventionally fractionated RT up to 59 Gy. • At doses ≥60 Gy, cumulative incidence of RION was <6% at 10 years. • Higher dose, older age, and female sex were risk factors for optic neuropathy. Abstract Introduction Radiation-induced optic neuropathy (RION) is a complication of radiation therapy (RT) that causes blindness. We aimed to define the tolerance of the anterior optic pathway to fractionated RT and identify risk factors for RION. Materials/methods Patients with chordoma or chondrosarcoma of the skull base treated with proton and photon therapy between 1983 and 2013, who received a minimum of 30 Gy (relative biologic effectiveness [RBE]) to the anterior optic pathway were assessed. Optic neuropathy with radiographic correlation occurring ≥6 months after completion of RT in the absence of tumor recurrence or other probable cause was diagnosed as RION. Results Of 514 patients, 17 developed RION. With median follow-up of 4.8 years, cumulative incidence of RION was 1% among patients receiving <59 Gy (RBE) and 5.8% among patients receiving ≥60 Gy (RBE) to the optic pathway. Higher maximum point dose to the optic pathway (subhazard ratio [SHR] = 1.2, 95% CI 1.05–1.2, p = 0.001), older age (SHR = 1.1, 95% CI 1.02–1.08, p < 0.0005), and female sex (SHR = 16.3, 95% CI 2.2–122.4, p = 0.007) were statistically significant risk factors for RION in multivariate analysis. Conclusion In our study cohort, rates of RION were very low with conventionally fractionated RT up to 59 Gy. At doses ≥60 Gy, there is an increased risk of RION, with greater risk for women and older patients. [ABSTRACT FROM AUTHOR]