title: Long-Term Results of Gamma Knife Radiosurgery for Intracranial Meningioma.
abstract: BACKGROUND
  The predominant treatment modality for meningioma is surgical resection. However, gamma knife radiosurgery is also an important treatment modality for meningioma that is small or cannot be completely removed because of its location. In this study, we evaluated the effectiveness and long-term results of radiosurgical treatment for meningioma in our institution.
  
  
  METHODS
  We studied 628 patients (130 men and 498 women) who underwent gamma knife radiosurgery for intracranial meningioma, which is radiologically diagnosed, from Jan 2008 to Nov 2012. We included patients with single lesion meningioma, and followed up after 6 months with imaging, and then at 24 months with a clinical examination. Patients with high-grade meningioma or multiple meningiomas were excluded. We analyzed each of the factors associated with progression free survival. The median patient's age was 56.8 years. Maximal dosage was 27.8 Gy and marginal dosage was 13.9 Gy.
  
  
  RESULTS
  The overall tumor control rate was 95%. Twenty-eight patients (4.4%) showed evidence of tumor recurrence. Ninety-eight patients (15%) developed peritumoral edema (PTE) after gamma-knife surgery; two of them (2%) underwent surgical resections due to PTE. Nine patients had craniotomy and tumor removal after gamma knife surgery.
  
  
  CONCLUSIONS
  Gamma knife surgery for intracranial meningioma has proven to be a safe and effective treatment tool with successful long-term outcomes. Gamma knife radiosurgery can be especially effective in cases of remnant meningioma after surgical resection or where PTE is not present.
authors.affiliation: Department of Neurosurgery, Yonsei Gamma Knife Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Chang Ki
authors.initials: CK
authors.lastname: Jang
authors.affiliation: Department of Neurosurgery, Yonsei Gamma Knife Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hyun Ho
authors.initials: HH
authors.lastname: Jung
authors.affiliation: Department of Neurosurgery, Yonsei Gamma Knife Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jong Hee
authors.initials: JH
authors.lastname: Chang
authors.affiliation: Department of Neurosurgery, Yonsei Gamma Knife Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jin Woo
authors.initials: JW
authors.lastname: Chang
authors.affiliation: Department of Neurosurgery, Yonsei Gamma Knife Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Yong Gou
authors.initials: YG
authors.lastname: Park
authors.affiliation: Department of Neurosurgery, Yonsei Gamma Knife Center, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Won Seok
authors.initials: WS
authors.lastname: Chang
keywords: Meningioma; Radiosurgery; Stereotactic