title: Five fraction image-guided radiosurgery for primary and recurrent meningiomas.
abstract: OBJECTIVE
  Benign tumors that arise from the meninges can be difficult to treat due to their potentially large size and proximity to critical structures such as cranial nerves and sinuses. Single fraction radiosurgery may increase the risk of symptomatic peritumoral edema. In this study, we report our results on the efficacy and safety of five fraction image-guided radiosurgery for benign meningiomas.
  
  
  METHODS
  Clinical and radiographic data from 38 patients treated with five fraction radiosurgery were reviewed retrospectively. Mean tumor volume was 3.83 mm(3) (range, 1.08-20.79 mm(3)). Radiation was delivered using the CyberKnife, a frameless robotic image-guided radiosurgery system with a median total dose of 25 Gy (range, 25-35 Gy).
  
  
  RESULTS
  The median follow-up was 20 months. Acute toxicity was minimal with eight patients (21%) requiring a short course of steroids for headache at the end of treatment. Pre-treatment neurological symptoms were present in 24 patients (63.2%). Post treatment, neurological symptoms resolved completely in 14 patients (58.3%), and were persistent in eight patients (33.3%). There were no local failures, 24 tumors remained stable (64%) and 14 regressed (36%). Pre-treatment peritumoral edema was observed in five patients (13.2%). Post-treatment asymptomatic peritumoral edema developed in five additional patients (13.2%). On multivariate analysis, pre-treatment peritumoral edema and location adjacent to a large vein were significant risk factors for radiographic post-treatment edema (p = 0.001 and p = 0.026 respectively).
  
  
  CONCLUSIONS
  These results suggest that five fraction image-guided radiosurgery is well tolerated with a response rate for neurologic symptoms that is similar to other standard treatment options. Rates of peritumoral edema and new cranial nerve deficits following five fraction radiosurgery were low. Longer follow-up is required to validate the safety and long-term effectiveness of this treatment approach.
authors: Department of Neurosurgery, Georgetown University Hospital , Washington, DC , USA ; Department of Radiation Medicine, Georgetown University Hospital , Washington, DC , USA.
authors: Eric Karl
authors: EK
authors: Oermann
authors: Rahul
authors: R
authors: Bhandari
authors: Viola J
authors: VJ
authors: Chen
authors: Gabriel
authors: G
authors: Lebec
authors: Marie
authors: M
authors: Gurka
authors: Siyuan
authors: S
authors: Lei
authors: Leonard
authors: L
authors: Chen
authors: Simeng
authors: S
authors: Suy
authors: Norio
authors: N
authors: Azumi
authors: Frank
authors: F
authors: Berkowitz
authors: Christopher
authors: C
authors: Kalhorn
authors: Kevin
authors: K
authors: McGrail
authors: Brian Timothy
authors: BT
authors: Collins
authors: Walter C
authors: WC
authors: Jean
authors: Sean P
authors: SP
authors: Collins
keywords: fractionation; meningioma; radiosurgery; toxicity; treatment outcome
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