title: Radiation therapy for optic nerve sheath meningioma.
abstract: OBJECTIVE
  To explain the concepts that radiation oncologists should understand to manage patients with optic nerve sheath meningioma (ONSM). To accomplish this goal we first describe our institution's experience with the treatment of ONSM with radiation therapy and then use this data set as a framework for explaining the role of radiation therapy in the treatment of this uncommon tumor.
  
  
  METHODS
  We studied the outcomes of all 15 patients treated at our medical center with radiation therapy for ONSM between 1990 and 2006. The minimum follow-up was 5 years (median, 12 years). The median dose was 50.4 Gy at 1.8 Gy per treatment (range, 50-54 Gy).
  
  
  RESULTS
  No patient experienced tumor progression. The rates of local control, regional control, and relapse free-survival were all 100%. Radiographic tumor response after radiation therapy was as follows: No change in 93%; and a reduction in size in 7%. Vision status after radiation therapy was as follows: Stable in 60%; improved in 27%; and decreased in 13%. Vision was classified as "useful" at last follow-up in 86% of patients with useful vision at the time of radiation therapy. The only treatment complication was moderate retinopathy in 2 patients. At last follow-up, no patient had developed a second tumor.
  
  
  CONCLUSIONS
  Radiation therapy with 50.4 Gy at 1.8 Gy per treatment prevents tumor growth and vision deterioration in most patients with ONSM.
authors.affiliation: Department of Radiation Oncology, University of Florida, Gainesville, Florida.
authors.forename: Jeffrey V
authors.initials: JV
authors.lastname: Brower
authors.affiliation: Department of Radiation Oncology, University of Florida, Gainesville, Florida. Electronic address: amdurr@shands.ufl.edu.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Amdur
authors.affiliation: Department of Radiation Oncology, University of Florida, Gainesville, Florida.
authors.forename: Jessica
authors.initials: J
authors.lastname: Kirwan
authors.affiliation: Department of Radiation Oncology, University of Florida, Gainesville, Florida.
authors.forename: William M
authors.initials: WM
authors.lastname: Mendenhall
authors.affiliation: Department of Neurosurgery, University of Florida, Gainesville, Florida.
authors.forename: William
authors.initials: W
authors.lastname: Friedman