title: Safety and efficacy of stereotactic body radiotherapy as primary treatment for vertebral metastases: a multi-institutional analysis.
abstract: OBJECTIVE
  To evaluate patient selection criteria, methodology, safety and clinical outcomes of stereotactic body radiotherapy (SBRT) for treatment of vertebral metastases.
  
  
  METHODS
  Eight centers from the United States (n=5), Canada (n=2) and Germany (n=1) participated in the retrospective study and analyzed 301 patients with 387 vertebral metastases. No patient had been exposed to prior radiation at the treatment site. All patients were treated with linac-based SBRT using cone-beam CT image-guidance and online correction of set-up errors in six degrees of freedom.
  
  
  RESULTS
  387 spinal metastases were treated and the median follow-up was 11.8 months. The median number of consecutive vertebrae treated in a single volume was one (range, 1-6), and the median total dose was 24 Gy (range 8-60 Gy) in 3 fractions (range 1-20). The median EQD210 was 38 Gy (range 12-81 Gy). Median overall survival (OS) was 19.5 months and local tumor control (LC) at two years was 83.9%. On multivariate analysis for OS, male sex (p<0.001; HR=0.44), performance status <90 (p<0.001; HR=0.46), presence of visceral metastases (p=0.007; HR=0.50), uncontrolled systemic disease (p=0.007; HR=0.45), >1 vertebra treated with SBRT (p=0.04; HR=0.62) were correlated with worse outcomes. For LC, an interval between primary diagnosis of cancer and SBRT of ≤ 30 months (p=0.01; HR=0.27) and histology of primary disease (NSCLC, renal cell cancer, melanoma, other) (p=0.01; HR=0.21) were correlated with worse LC. Vertebral compression fractures progressed and developed de novo in 4.1% and 3.6%, respectively. Other adverse events were rare and no radiation induced myelopathy reported.
  
  
  CONCLUSIONS
  This multi-institutional cohort study reports high rates of efficacy with spine SBRT. At this time the optimal fractionation within high dose practice is unknown.
authors.affiliation: Department of Radiation Oncology, University of Wuerzburg, Wuerzburg, Germany. Matthias.Guckenberger@usz.ch.|Department of Radiation Oncology, University of Zurich, Zurich, Switzerland. Matthias.Guckenberger@usz.ch.
authors.forename: Matthias
authors.initials: M
authors.lastname: Guckenberger
authors.affiliation: Department of Radiation Oncology, University of Wuerzburg, Wuerzburg, Germany. mantel_f@ukw.de.
authors.forename: Frederick
authors.initials: F
authors.lastname: Mantel
authors.affiliation: Department Radiation Oncology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA. gerspc@UPMC.EDU.|Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA. gerspc@UPMC.EDU.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Gerszten
authors.affiliation: Department Radiation Oncology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA. flickingerjc@upmc.edu.|Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA. flickingerjc@upmc.edu.
authors.forename: John C
authors.initials: JC
authors.lastname: Flickinger
authors.affiliation: Department of Radiation Oncology, Sunnybrook Odette Cancer Centre, Toronto, Canada. Arjun.Sahgal@sunnybrook.ca.
authors.forename: Arjun
authors.initials: A
authors.lastname: Sahgal
authors.affiliation: Department of Radiation Oncology, Princess Margaret Hospital, Toronto, Canada. Daniel.Letourneau@rmp.uhn.on.ca.
authors.forename: Daniel
authors.initials: D
authors.lastname: Létourneau
authors.affiliation: Department of Radiation Oncology, Beaumont Health System, Oakland University William Beaumont School of Medicine, Royal Oak, MI, USA. IGrills@beaumont.edu.
authors.forename: Inga S
authors.initials: IS
authors.lastname: Grills
authors.affiliation: Department of Radiation Oncology, Beaumont Health System, Oakland University William Beaumont School of Medicine, Royal Oak, MI, USA. Maha.Jawad@beaumont.edu.
authors.forename: Maha
authors.initials: M
authors.lastname: Jawad
authors.affiliation: Department of Neurosurgery, Beaumont Health System, Oakland University William Beaumont School of Medicine, Royal Oak, MI, USA. Daniel.Fahim@beaumont.edu.
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Fahim
authors.affiliation: Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA. Shin.John@mgh.harvard.edu.
authors.forename: John H
authors.initials: JH
authors.lastname: Shin
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, USA. Winey.Brian@mgh.harvard.edu.
authors.forename: Brian
authors.initials: B
authors.lastname: Winey
authors.affiliation: Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, VA, USA. jps2f@virginia.edu.
authors.forename: Jason
authors.initials: J
authors.lastname: Sheehan
authors.affiliation: Riverside Medical Center, Newport News, VA, USA. Ronald.Kersh@rivhs.com.
authors.forename: Ron
authors.initials: R
authors.lastname: Kersh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009369:Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D011379:Prognosis; D016634:Radiosurgery; D012189:Retrospective Studies; D012449:Safety; D013125:Spinal Neoplasms / Q000401:mortality / Q000556:secondary / Q000601:surgery*; D015996:Survival Rate; D055815:Young Adult