Single-session stereotactic radiosurgery for large perioptic meningiomas.

[OBJECTIVE] Meningiomas close to the optic pathway are commonly candidates for microsurgical decompression, more so if they are large perioptic meningiomas. However, microsurgery itself imposes risk to vision, and the larger the tumor, the more the risk and the lower the possibility of postoperative visual recovery. Fractionated stereotactic radiotherapy is usually reserved for such cases. The purpose of this study was to assess the long-term efficacy and safety of single-session stereotactic radiosurgery (SRS) for large (≥ 10 cm3) perioptic intracranial benign meningiomas.

[METHODS] This retrospective study included 175 patients with large perioptic benign meningiomas (≥ 10 cm3) who were treated by single-session SRS. Perioptic meningiomas were defined as meningiomas touching, compressing, or within 3 mm of the optic pathway. The median tumor volume was 15 cm3 (range 10-57.3 cm3, IQR 8.4 cm3). The median prescription dose was 12 Gy (range 9-14 Gy, IQR 1 Gy).

[RESULTS] The median follow-up period was 72 months (range 13-217 months, IQR 65 months). The tumor control rate was 92%. The progression-free survival rates at 5 and 10 years were 97% and 80%, respectively. Favorable (better/stable) visual outcome was reported in 169 patients (97%) and unfavorable (worse) outcome in 6 patients (3%). Temporary adverse radiation effects were observed in 21 patients (12%), but only 7 patients (4%) were symptomatic. Sixty-three patients had a blind/nonuseful eye according to the pretreatment visual field examination. Visual improvement was observed in the blind/nonuseful eye in 17 patients (27%), while vision remained unchanged in 46 patients (73%). Ocular nerve palsy improved in 36 patients (61%). Tumor shrinkage was not a prerequisite for cranial nerve improvement.

[CONCLUSIONS] SRS provides an effective and safe treatment option for large perioptic meningiomas.