title: Long-term outcomes of fractionated stereotactic radiotherapy for intracranial skull base benign meningiomas in single institution.
abstract: OBJECTIVE
  To investigate the outcome of linac-based fractionated stereotactic radiotherapy over the last 10 years for intracranial skull base benign meningiomas in patients who were inoperable, who had residual tumors with some components of high mitotic index after surgery and who experienced relapse of the tumor.
  
  
  METHODS
  Twenty-seven patients with intracranial skull base benign meningiomas treated with fractionated stereotactic radiotherapy were retrospectively reviewed. Twenty-seven cases were diagnosed as benign meningiomas on pathological (17 cases) or radiological (10 cases) examination. The median follow-up time was 90 months after initial treatment and 63 months after fractionated stereotactic radiotherapy. The median biological equivalent dose calculated using an α/β ratio of 2.0 Gy was 82.0 Gy (range, 60-106 Gy).
  
  
  RESULTS
  The 5-year overall survival was 95.7 (95% confidence interval: 87.3-100)% after initial treatment and 96.2 (88.8-100)% after fractionated stereotactic radiotherapy. The 5-year overall survival and local control rate of patients who received fractionated stereotactic radiotherapy alone were both 100%. The 5-year progression-free survival and local control rate after fractionated stereotactic radiotherapy were all 100% with a tumor volume of <9.1 cc and 68.2 (37.2-99.2) and 75.8 (45.2-100)% for the tumors 9.1 cc, respectively. The difference was significant in progression-free survival (P = 0.022) and local control rate (P = 0.044). The local control rate was significantly worse in patients who received fractionated stereotactic radiotherapy for relapsed tumors (P = 0.01). No late radiation damage was observed in the follow-up period.
  
  
  CONCLUSIONS
  The long-term outcome suggests that fractionated stereotactic radiotherapy is a safe and effective treatment for intracranial skull base benign meningioma, especially for those who have tumors <9.1 cc or would receive fractionated stereotactic radiotherapy with or without surgery as the initial treatment.
authors.affiliation: Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan. m950086@jasmine.ocn.ne.jp
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Onodera
authors.forename: Hidefumi
authors.initials: H
authors.lastname: Aoyama
authors.forename: Norio
authors.initials: N
authors.lastname: Katoh
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Taguchi
authors.forename: Kouichi
authors.initials: K
authors.lastname: Yasuda
authors.forename: Daisuke
authors.initials: D
authors.lastname: Yoshida
authors.forename: Ken
authors.initials: K
authors.lastname: Surtherland
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Suzuki
authors.forename: Masayori
authors.initials: M
authors.lastname: Ishikawa
authors.forename: Bengua
authors.initials: B
authors.lastname: Gerard
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Terasaka
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shirato
mesh_terms: D000328:Adult; D000368:Aged; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D008579:Meningioma / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D008875:Middle Aged; D008940:Mitotic Index; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D011859:Radiography; D016634:Radiosurgery / Q000379:methods; D012189:Retrospective Studies; D019291:Skull Base; D013997:Time Factors; D016896:Treatment Outcome