Purpose: Comparison of treatment outcome in patients with primary optic nerve sheath meningioma (ONSM).
Design: Retrospective, nonrandomized, comparative interventional case series.
Participants: Sixty-four patients with at least 50 months of well-documented follow-up.
Intervention: Observation, surgery only, radiotherapy only, or surgery and radiotherapy.
Main outcome measures: Visual acuity expressed as ratio, radiographic progression, and treatment complications.
Results: Sixty-four patients (55 women [85.9%] and nine men [14.1%]) were followed for a mean of 150.2 months (range, 51-516 months; standard deviation [SD], 74.7). The mean age at diagnosis was 47.1 years (range, 17-81 years; SD, 15.4). Fifty-eight patients had unilateral disease and six patients had bilateral disease. Of 59 patients with vision greater than no light perception at diagnosis, 13 patients were observed only, 12 had surgery only (four biopsies or partial resections, eight total resections), 18 received radiation alone, and 16 had surgery and radiation (14 biopsies or partial resections and radiation, two total resections and radiation). Irradiated patients received 4000 to 5500 cGy of conventional multiport or conformal external beam therapy, typically fractionated over 6 weeks. Visual acuity measurements at diagnosis among the four groups were not different (ratio, P = 0.186). Visual acuity at diagnosis was > or =0.5 in 56.3%, 0.4 to 0.050 in 12.5%, and <0.050 in 31.3%. Visual acuity measures at last follow-up were different among the four groups (ratio, P = 0.004). At last follow-up the acuity was > or =0.5 in 28.1%, 0.4 to 0.050 in 15.6%, and <0.050 in 56.3%. Visual acuity fell significantly for the observed only (ratio, P = 0.002), surgery only (ratio, P = 0.019), and surgery with radiation groups (ratio, P = 0.030). The radiation only group showed a decrease in visual acuity that was not significant (ratio, P = 0.301). Complication rate was 33.3% in radiation only cases, 66.7% in surgery only cases, and 62.5% in surgery with radiation cases. Twenty-one patients (32.8%) showed radiographic progression. Four patients who were observed, seven patients who had surgery alone, and eight patients who had surgery and radiation developed radiographic progression. Two patients who had radiation alone had radiographic progression before treatment. Only two patients treated with radiation only showed radiographic progression after radiotherapy, and both had at least one surgical procedure before the radiotherapy.
Conclusions: Patients with ONSM receiving radiation alone demonstrated the best visual outcome during the follow-up period. We recommend that fractionated external beam radiation (5000-5500 cGy) be considered as initial treatment in adults in selected cases of ONSM when preservation of visual function is a reasonable therapeutic goal.