Background/Aims: To review the long term results of treatment of optic nerve sheath meningiomas (ONSM) with conformal radiotherapy.
Methods: Eleven patients with presumed ONSM were treated with fractionated conformal radiotherapy using 45 to 54 Gy in 25 to 29 fractions and followed for more than 5 years. Affected eye visual acuity in LogMar notation, color vision, threshold perimetry, mean deviation (db), and imaging were studied before and after treatment.
Analysis: Included adverse effects of treatment and the frequency of affected eye maintained or improved vision.
Results: There were 9 women and 2 men with a mean age of 45.3. Vision or field loss was the most common presentation. All had abnormal MR imaging. Follow-up period after radiotherapy was 61 to 156 months (mean 89.6). Visual acuity was unchanged or improved in 10 patients(91%). The average difference between pre-treatment and final LogMar visual acuity was 0.08, while average difference in visual field mean deviation was -4.63 dB. The radiographic appearance of the tumors was stable in size in 9 patients and decreased in 2. No major side effects from radiation were seen.
Conclusions: Vision, MRI, and complication outcomes are favorable for using fractionated conformal radiotherapy for ONSM.