title: Volumetric response of intracranial meningioma after photon or particle irradiation.
abstract: BACKGROUND
  Meningiomas are usually slow growing, well circumscribed intracranial tumors. In symptom-free cases observation with close follow-up imaging could be performed. Symptomatic meningiomas could be surgically removed and/or treated with radiotherapy. The study aimed to evaluate the volumetric response of intracranial meningiomas at different time points after photon, proton, and a mixed photon and carbon ion boost irradiation.
  
  
  METHODS
  In Group A 38 patients received proton therapy (median dose: 56 GyE in 1.8-2 GyE daily fractions) or a mixed photon/carbon ion therapy (50 Gy in 2 Gy daily fractions with intensity modulated radiotherapy (IMRT) and 18 GyE in 3 GyE daily dose carbon ion boost). Thirty-nine patients (Group B) were treated by photon therapy with IMRT or fractionated stereotactic radiotherapy technique (median dose: 56 Gy in 1.8-2 Gy daily fractions). The delineation of the tumor volume was based on the initial, one- and two-year follow-up magnetic resonance imaging and these volumes were compared to evaluate the volumetric tumor response.
  
  
  RESULTS
  Significant tumor volume shrinkage was detected at one- and at two-year follow-up both after irradiation by particles and by photons. No significant difference in tumor volume change was observed between photon, proton or combined photon plus carbon ion boost treated patients. WHO grade and gender appear to be determining factors for tumor volume shrinkage.
  
  
  CONCLUSIONS
  Significant volumetric shrinkage of meningiomas could be observed independently of the applied radiation modality. Long-term follow-up is recommended to evaluate further dynamic of size reduction and its correlation with outcome data.
authors.affiliation: a Department of Radiation Oncology , Klinikum rechts der Isar, Technische Universität München , Munich , Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Mozes
authors.affiliation: a Department of Radiation Oncology , Klinikum rechts der Isar, Technische Universität München , Munich , Germany.
authors.forename: Jan Oliver
authors.initials: JO
authors.lastname: Dittmar
authors.affiliation: a Department of Radiation Oncology , Klinikum rechts der Isar, Technische Universität München , Munich , Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Habermehl
authors.affiliation: b Department of Radiation Oncology , University Hospital of Heidelberg , Heidelberg , Germany.
authors.forename: Eric
authors.initials: E
authors.lastname: Tonndorf-Martini
authors.affiliation: c Department of Oncotherapy, Faculty of Medicine , University of Szeged , Szeged , Hungary.|d Attosecond Light Pulse Source, ELI-Hu Nkft , Szeged , Hungary.
authors.forename: Katalin
authors.initials: K
authors.lastname: Hideghety
authors.affiliation: b Department of Radiation Oncology , University Hospital of Heidelberg , Heidelberg , Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Dittmar
authors.affiliation: b Department of Radiation Oncology , University Hospital of Heidelberg , Heidelberg , Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Debus
authors.affiliation: a Department of Radiation Oncology , Klinikum rechts der Isar, Technische Universität München , Munich , Germany.|e Institute of Innovative Radiotherapy, Department of Radiation Sciences , Helmholtz Zentrum München , Neuherberg , Germany.
authors.forename: Stephanie E
authors.initials: SE
authors.lastname: Combs
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000473:pathology / Q000532:radiotherapy; D016022:Case-Control Studies; D005260:Female; D063193:Heavy Ion Radiotherapy; D006801:Humans; D008297:Male; D008577:Meningeal Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D008579:Meningioma / Q000473:pathology* / Q000532:radiotherapy*; D008875:Middle Aged; D017785:Photons; D061766:Proton Therapy; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies; D016896:Treatment Outcome; D047368:Tumor Burden / Q000528:radiation effects*; D055815:Young Adult