title: Spot scanning-based proton therapy for intracranial meningioma: long-term results from the Paul Scherrer Institute.
abstract: BACKGROUND
  To assess the long-term clinical results of spot scanning proton therapy (PT) in the treatment of intracranial meningiomas.
  
  
  METHODS
  Thirty-nine patients with meningioma (histologically proven 34/39) were treated with PT between July 1997 and January 2010. Thirty-two (82.1%) patients were treated as primary treatment (exclusive PT, n = 8; postoperative PT, n = 24). Mean age was 48.3 ± 17.9 years and 32 (82.1%) patients had skull base lesions. For patients undergoing surgery, 24 patients had a diagnosis of World Health Organization (WHO) Grade I and 10 of a WHO Grade II/III meningioma, respectively. The female-to-male ratio was 3.3. The median administered dose was 56.0 Gy (relative biologic effectiveness [RBE]) (range, 52.2-66.6) at 1.8-2.0 Gy (RBE) per fraction. Gross tumor volume (GTV) ranged from 0.76 to 546.5 cm(3) (median, 21.5). Late toxicity was assessed according to Common Terminology Criteria for Adverse Events version 3.0. Mean follow-up time was 62.0 months and all patients were followed for >6 months.
  
  
  RESULTS
  Six patients presented with tumor recurrence and 6 patients died during follow-up, of which 4 of tumor progression. Five-year actuarial local control and overall survival rates were 84.8% and 81.8%, respectively, for the entire cohort and 100% for benign histology. Cumulative 5-year Grade ≥3 late toxicity-free survival was 84.5%. On univariate analysis, LC was negatively influenced by WHO grade (p = 0.001), GTV (p = 0.013), and male gender (p = 0.058).
  
  
  CONCLUSIONS
  PT is a safe and effective treatment for patients with untreated, recurrent, or incompletely resected intracranial meningiomas. WHO grade and tumor volume was an adverse prognostic factor for local control.
authors.affiliation: Radiation Oncology, Geneva University Hospital, Geneva, Switzerland. damien.weber@unige.ch
authors.forename: Damien C
authors.initials: DC
authors.lastname: Weber
authors.forename: Ralf
authors.initials: R
authors.lastname: Schneider
authors.forename: Gudrun
authors.initials: G
authors.lastname: Goitein
authors.forename: Tamara
authors.initials: T
authors.lastname: Koch
authors.forename: Carmen
authors.initials: C
authors.lastname: Ares
authors.forename: Jan H
authors.initials: JH
authors.lastname: Geismar
authors.forename: Andreas
authors.initials: A
authors.lastname: Schertler
authors.forename: Alessandra
authors.initials: A
authors.lastname: Bolsi
authors.forename: Eugen B
authors.initials: EB
authors.lastname: Hug
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002173:Cancer Care Facilities; D002648:Child; D002675:Child, Preschool; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D008579:Meningioma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality; D061766:Proton Therapy; D011522:Protons / Q000009:adverse effects; D012062:Relative Biological Effectiveness; D016879:Salvage Therapy / Q000379:methods; D012737:Sex Factors; D019292:Skull Base Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery; D015996:Survival Rate; D013557:Switzerland; D047368:Tumor Burden; D055815:Young Adult
chemical_list: D011522:Protons