Optic nerve sheath meningiomas--non-surgical treatment.

AIMS: Optic nerve sheath meningiomas typically present with unilateral visual deterioration. Here, a single centre's experience with radiotherapy aimed at local control and visual stabilisation is presented.
MATERIALS AND METHODS: The meningioma database within the Radiation Oncology Department, Prince of Wales Hospital was audited for patients whose meningiomas took origin from the optic nerve sheath. Excluded from this evaluation was any patient whose meningioma secondarily involved the optic nerve. Where vision was not a consideration, treatment was given by stereotactic radiosurgery for patients with retained vision. The remaining patients were treated by fractionated radiotherapy, predominately via a stereotactic approach. The main end points were: lack of radiological progression of the tumour and maintenance of preradiotherapy vision.
RESULTS: There were 15 eligible patients, one patient with neurofibromatosis had bilateral optic nerve involvement; thus, 16 optic nerves were treated. Women (10) outnumbered men (five) and the age range was 7-74 years. One patient progressed outside the volume treated (for a geographical failure) with no infield progression. This patient became blind, was re-treated by stereotactic radiosurgery, had tumour control and vision improved. Thus, for 17 optic nerves (or part thereof) treated, all patients ultimately had local control (100%) with worsening of vision only occurring in one patient. No other late morbidity was present for any patient.
CONCLUSION: Optic nerve sheath meningiomas have high local control rates and preservation of vision with radiotherapy.