title: Long-term outcomes of Gamma Knife surgery for cavernous sinus meningioma.
abstract: OBJECTIVE
  The aim of this study was to evaluate long-term outcomes, including tumor control and neurological function, in patients with cavernous sinus meningiomas treated using Gamma Knife surgery (GKS).
  
  
  METHODS
  One hundred fifteen patients with cavernous sinus meningiomas, excluding atypical or malignant meningiomas, were treated with GKS between 1991 and 2003. Forty-nine patients (43%) underwent GKS as the initial treatment. The mean tumor volume was 14 cm3, and the mean maximum and margin doses applied to the tumor were 27 and 13 Gy, respectively. The median follow-up period was 62 months. During the follow-up, 111 patients were able to be evaluated with neuroimaging.
  
  
  RESULTS
  The actuarial 5- and 10-year progression-free survival rates were 87 and 73%, respectively. Similarly, the actuarial 5- and 10-year focal tumor control rates were 94 and 92%, respectively. Regarding functional outcomes, 43 patients (46%) experienced some degree of improvement, 40 (43%) remained stable, and 11 (12%) had worse preexisting or newly developed symptoms. Patients who underwent GKS as the initial treatment experienced significant improvement of their symptoms (p = 0.006).
  
  
  CONCLUSIONS
  Gamma Knife surgery is a safe and effective treatment over the long term in selected patients with cavernous sinus meningiomas. Tumor progression is more likely to occur from the lesion margin outside the treatment volume. In small to medium-sized tumors, GKS is an excellent alternative to resection, preserving good neurological function. For relatively large-sized tumors, low-dose radiosurgery (< or = 12 Gy) is acceptable for the prevention of tumor progression.
authors.affiliation: Department of Neurosurgery, Gamma Knife Center, Komaki City Hospital, Komaki, Japan. h-toshi@komakihp.gr.jp
authors.forename: Toshinori
authors.initials: T
authors.lastname: Hasegawa
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Kida
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yoshimoto
authors.forename: Joji
authors.initials: J
authors.lastname: Koike
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iizuka
authors.forename: Dai
authors.initials: D
authors.lastname: Ishii
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002426:Cavernous Sinus / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008577:Meningeal Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D008579:Meningioma / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D008875:Middle Aged; D009017:Morbidity; D011379:Prognosis; D011829:Radiation Dosage; D016634:Radiosurgery / Q000401:mortality; D015996:Survival Rate; D013997:Time Factors; D016896:Treatment Outcome