Clinical outcomes of fractionated stereotactic radiosurgery in treating perioptic meningiomas and schwannomas: A single-institutional experience.

Application of radiosurgery to the newly diagnosed or post-operative residual perioptic lesions has been proved to improve tumor control. However, risk of vision injury induced by radiosurgery may increase substantially if the radiation dose is too high or tumor is close to the optic apparatus. The purpose of this study was to evaluate the safety and the effectiveness of fractionated stereotactic radiosurgery (FSRS) for perioptic tumors. We retrospectively analyzed 60 consecutive patients with 53 meningiomas and 7 schwannomas treated with FSRS between October 2007 and February 2020. We administered a marginal dose of 6-7 Gy (mean 6.8 Gy) per fraction and delivered 3 fractions in 3 consecutive days. The median tumor volume was 6.31 cm (range 0.3-58.23 cm). The mean minimum lesion-optic distance (MLOD) is 0.85 mm (range 0-3 mm). After mean follow-up period of 69.6 months (range 6.82-156.32 months; median 58.9 months), the tumor control rates at 1, 3, 5, 8 and 13 years were 98.3%, 93.4%, 90.60%, 88.4% and 88.4%, respectively. Four out of the 60 tumors (6.7%) experienced a transient volume increase after FSRS. None of the patients developed visual impairment related to radiation induced optic neuropathy (RION) after FSRS. In conclusion, FSRS offers an alternative treatment option in treating perioptic meningiomas and schwannomas with acceptable tumor control rates and good visual preservation in the present study.