title: Radiotherapy for atypical or malignant intracranial meningioma.
abstract: OBJECTIVE
  To study the natural history of intracranial atypical and malignant meningiomas, and the role of radiotherapy in the treatment of these tumors.
  
  
  METHODS
  The records of the 59 patients who were treated at the Princess Margaret Hospital between 1966 and 1990 with histologically confirmed intracranial atypical or malignant meningiomas were retrospectively reviewed. The median age was 58 years. Twenty-four patients were referred for radiation immediately after diagnosis and the remainder after at least one recurrence. The extent of the most recent surgery prior to radiation was gross total excision in 17, subtotal excision in 35, biopsy in 3, and none or unknown in 4. Seventeen had atypical meningiomas, defined as the presence of mitoses, nuclear atypia, or necrosis. Forty-two had malignant meningiomas on the basis of brain invasion (60%) or a pathologist's designation of malignant or hemangiopericytic meningioma. All patients received megavoltage radiation to a median dose of 50 Gy.
  
  
  RESULTS
  Disease progressed in 39 patients (66%) after radiation. Of these, 36 died of meningioma and 3 were alive after further surgery. The 5-year actuarial overall and cause-specific survivals were 28 and 34%, respectively. Age less than 58, treatment after 1975, and a radiation dose of 50 Gy or more were independently associated with higher cause-specific survival by multivariate analysis.
  
  
  CONCLUSIONS
  Young age, modern imaging and treatment planning techniques, and a postoperative radiation dose of at least 50 Gy contribute to improved outcome in patients with atypical or malignant meningiomas. We recommend that all patients receive radiotherapy immediately after initial surgery.
authors.affiliation: Department of Radiation Oncology, University of Toronto, Ontario, Canada.
authors.forename: M F
authors.initials: MF
authors.lastname: Milosevic
authors.forename: P J
authors.initials: PJ
authors.lastname: Frost
authors.forename: N J
authors.initials: NJ
authors.lastname: Laperriere
authors.forename: C S
authors.initials: CS
authors.lastname: Wong
authors.forename: W J
authors.initials: WJ
authors.lastname: Simpson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D008579:Meningioma / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000532:radiotherapy; D012189:Retrospective Studies; D016019:Survival Analysis