Hypofractionated Stereotactic Radiotherapy for Patients with Intracranial Meningiomas: impact of radiotherapy regimen on local control.

We evaluated efficacy and tolerance of hypofractionated stereotactic radiation treatment (hFSRT) in the management of intracranial meningiomas. Between December 2008 and June 2016, 126 patients with 136 intracranial meningiomas were treated with robotic hFSRT. hFSRT was performed as primary irradiation and as a salvage option for the local recurrence after prior radiotherapy. The median prescription dose was 25 Gy (12-40) with a median number of fractions of 5 (3-10). After a median follow-up of 20.3 months (range 1-77 months), the 24-months local control (LC) rate was 81% in the primary hFSRT group and 39% after hFSRT in the re-irradiation group (p=0.002). The clinical control rate of symptoms in the overall population was 95% (95% CI: 89-98%). Progression-free survival (PFS) in the overall population at 24 months was 70% (95% CI: 60%-79%). In the primary hFSRT group, PFS was significantly lower with the most hypofractionated schedules of 21-23 Gy in 3 fractions vs. 25-40 Gy in 5-10 fractions: 62% vs. 92% (p = 0.0006). The incidence of radionecrosis at 24 months was significantly lower in the primary hFSRT group, at 2% vs. 20% in the re-irradiation hFSRT group (p = 0.002).