Preliminary visual outcomes after three-dimensional conformal radiation therapy for optic nerve sheath meningioma.
OBJECTIVE
We assessed visual outcomes, local control, and toxicity associated with three-dimensional conformal radiation therapy (3D-CRT) for primary optic nerve sheath meningiomas (ONSM).


METHODS
Twenty-three patients diagnosed with ONSM were evaluated at the University of Michigan between 1986 and 2001. Fourteen patients were treated with 3D-CRT. Detailed pre- and postradiation treatment ophthalmologic examinations and MRIs were performed on all patients. Clinically significant visual acuity change was defined as a >or=three line change on the Snellen chart. Mean deviation change of >or=three decibels was defined as a clinically significant visual field change. Radiographic progression was defined as any increase in size on MRI. Acute and late toxicity was scored according to RTOG criteria.


RESULTS
Median follow-up was 51.3 months. Five patients had a clinically significant improvement in visual acuity. Seven had stable acuity, and only 2 worsened. Nine patients had clinically significant visual field improvement. One patient developed early radiation retinopathy, 1 experienced orbital pain, 1 developed dry eye, and 2 developed iritis. No patient has required additional treatment, and none have demonstrated radiographic progression.


CONCLUSIONS
3D-CRT is effective in controlling tumor growth while improving or preserving vision in most patients with optic nerve sheath meningiomas.
Department of Radiation Oncology, University of Michigan Health Care System, Ann Arbor, MI 48109, USA. narayan@umich.edu
Samir
S
Narayan
Wayne T
WT
Cornblath
Howard M
HM
Sandler
Victor
V
Elner
James A
JA
Hayman
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000532:radiotherapy; D008579:Meningioma / Q000532:radiotherapy*; D008875:Middle Aged; D019574:Optic Nerve Neoplasms / Q000532:radiotherapy*; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods*; D016896:Treatment Outcome; D014786:Vision Disorders / Q000209:etiology / Q000532:radiotherapy*; D014792:Visual Acuity