title: 3D quantitative assessment of response to fractionated stereotactic radiotherapy and single-session stereotactic radiosurgery of vestibular schwannoma.
abstract: OBJECTIVE
  To determine clinical outcome of patients with vestibular schwannoma (VS) after treatment with fractionated stereotactic radiotherapy (FSRT) and single-session stereotactic radiosurgery (SRS) by using 3D quantitative response assessment on MRI.
  
  
  METHODS
  This retrospective analysis included 162 patients who underwent radiation therapy for sporadic VS. Measurements on T1-weighted contrast-enhanced MRI (in 2-year post-therapy intervals: 0-2, 2-4, 4-6, 6-8, 8-10, 10-12 years) were taken for total tumour volume (TTV) and enhancing tumour volume (ETV) based on a semi-automated technique. Patients were considered non-responders (NRs) if they required subsequent microsurgical resection or developed radiological progression and tumour-related symptoms.
  
  
  RESULTS
  Median follow-up was 4.1 years (range: 0.4-12.0). TTV and ETV decreased for both the FSRT and SRS groups. However, only the FSRT group achieved significant tumour shrinkage (p < 0.015 for TTV, p < 0.005 for ETV over time). The 11 NRs showed proportionally greater TTV (median TTV pre-treatment: 0.61 cm(3), 8-10 years after: 1.77 cm(3)) and ETV despite radiation therapy compared to responders (median TTV pre-treatment: 1.06 cm(3); 10-12 years after: 0.81 cm(3); p = 0.001).
  
  
  CONCLUSIONS
  3D quantification of VS showed a significant decrease in TTV and ETV on FSRT-treated patients only. NR had significantly greater TTV and ETV over time.
  
  
  CONCLUSIONS
  Only FSRT not GK-treated patients showed significant tumour shrinkage over time. Clinical non-responders showed significantly less tumour shrinkage when compared to responders. 3D volumetric assessment of vestibular schwannoma shows advantages over unidimensional techniques.
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Sciences, Division of Neuroradiology, The Johns Hopkins Hospital School of Medicine, Baltimore, MD, 21287, USA. tan.schneider@uke.de.|Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany. tan.schneider@uke.de.
authors.forename: T
authors.identifier: http://orcid.org/0000-0002-3767-5963
authors.initials: T
authors.lastname: Schneider
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Sciences, Division of Interventional Radiology, The Johns Hopkins Hospital School of Medicine, Baltimore, MD, 21287, USA.
authors.forename: J
authors.initials: J
authors.lastname: Chapiro
authors.affiliation: Ultrasound Imaging and Interventions (UII), Philips Research North America, Briarcliff Manor, NY, USA.
authors.forename: M
authors.initials: M
authors.lastname: Lin
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Sciences, Division of Interventional Radiology, The Johns Hopkins Hospital School of Medicine, Baltimore, MD, 21287, USA.|Department of Radiology and Imaging Science, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: J F
authors.initials: JF
authors.lastname: Geschwind
authors.affiliation: Department of Radiation Oncology and Molecular Radiation Sciences, Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA.
authors.forename: L
authors.initials: L
authors.lastname: Kleinberg
authors.affiliation: Department of Neurological Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA.
authors.forename: D
authors.initials: D
authors.lastname: Rigamonti
authors.affiliation: Department of Neurological Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA.
authors.forename: I
authors.initials: I
authors.lastname: Jusué-Torres
authors.affiliation: Department of Neurological Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, 21287, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Marciscano
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Sciences, Division of Neuroradiology, The Johns Hopkins Hospital School of Medicine, Baltimore, MD, 21287, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Yousem
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000473:pathology / Q000601:surgery*; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome; D047368:Tumor Burden
keywords: Benign neoplasms; Gamma Knife radiosurgery; Magnetic resonance imaging; Radiotherapy; Vestibular schwannoma