title: Stereotactic radiosurgery for radiation-induced meningiomas.
abstract: OBJECTIVE
  Radiation-induced meningiomas of the brain are typically managed with surgical resection. Stereotactic radiosurgery (SRS) has become an important primary or adjuvant management for patients with intracranial meningiomas, but the value of this approach for radiation-induced tumors is unclear.
  
  
  METHODS
  This series consisted of 19 patients (mean age, 40 years) with 24 tumors. The patients met criteria for a radiation-induced meningioma and underwent gamma knife radiosurgery. Seven patients had undergone a previous resection. The World Health Organization tumor grades for those with prior histology were Grade I (n = 5) and Grade II (n = 2). The median tumor volume was 4.4 cm3. Radiosurgery was performed using a median margin dose of 13 Gy.
  
  
  RESULTS
  Serial imaging was evaluated in all patients at a median follow-up of 44 months. The control rate was 75% after primary radiosurgery. Delayed resection after radiosurgery was performed in 5 patients (26%) at an average of 39 months. The median latency between radiation therapy for original disease and SRS for radiation-induced meningiomas was 29.7 years (range, 7.3-59.0 years). The overall survival after SRS was 94.1% and 80.7% at 3 and 5 years, respectively. No patient developed a subsequent radiation-induced tumor. The overall morbidity rate was 5.3% (1 optic neuropathy). Asymptomatic peritumoral imaging changes compatible with an adverse radiation effect developed in 1 patient.
  
  
  CONCLUSIONS
  SRS provides satisfactory control rates either after resection or as an alternative to resection. Its role is most valuable for patients whose tumors affect critical neurological regions and who are poor candidates for resection.
authors.affiliation: Department of Neurological Surgery, Center for Image-Guided Neurosurgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA. kondziolkads@upmc.edu
authors.forename: Douglas
authors.initials: D
authors.lastname: Kondziolka
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kano
authors.forename: Hilal
authors.initials: H
authors.lastname: Kanaan
authors.forename: Ricky
authors.initials: R
authors.lastname: Madhok
authors.forename: David
authors.initials: D
authors.lastname: Mathieu
authors.forename: John C
authors.initials: JC
authors.lastname: Flickinger
authors.forename: L Dade
authors.initials: LD
authors.lastname: Lunsford
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000209:etiology / Q000601:surgery; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000532:radiotherapy* / Q000601:surgery*; D008579:Meningioma / Q000209:etiology* / Q000601:surgery*; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000209:etiology* / Q000601:surgery*; D016634:Radiosurgery / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000009:adverse effects*; D016896:Treatment Outcome; D055815:Young Adult