title: Stereotactic Ablative Body Radiotherapy for the Treatment of Spinal Oligometastases.
abstract: OBJECTIVE
  To report multicentre outcomes of patients with spinal oligometastases treated with stereotactic ablative body radiotherapy (SABR). The primary objective was to estimate the widespread failure-free survival (WFFS) at 2 years - defined as freedom from metastases not amenable to local salvage therapy and death.
  
  
  METHODS
  Patients with one to three metastases treated with spinal SABR between January 2010 and July 2014 at four academic institutions were included in this retrospective review. The median dose/fractionation was 24 Gy (range 16-52.5 Gy) in two fractions (range one to three) and the median biologically effective dose (α/β=10) was 52.5 Gy (range 40-144.4 Gy). The WFFS, overall survival, freedom from local progression and toxicity rates were described using Kaplan-Meier statistics.
  
  
  RESULTS
  In total, 60 patients with 72 spinal metastases were analysed. The median follow-up was 21 months. Patients had a median age of 66 years, Eastern Cooperative Oncology Group performance 0-1 in 97% and metachronous oligometastases in 85%. The 1 and 2 year WFFS rates were 67% (95% confidence interval 55-80) and 59% (95% confidence interval 47-75), respectively. The 1 and 2 year overall survival rates were 90% (95% confidence interval 83-98) and 76% (95% confidence interval 64-91), respectively. The 1 and 2 year freedom from local progression were 92% (95% confidence interval 85-99) and 86% (95% confidence interval 75-99), respectively. There were four cases (6.7%) of vertebral compression fracture and no cases of radiation myelopathy.
  
  
  CONCLUSIONS
  Despite the use of relatively low biological doses respecting spinal cord constraints, SABR results in excellent 2 year local control rates with low morbidity. Through careful selection of patients with oligometastases, most patients are alive and free from widespread metastases at 2 years. This cohort warrants further investigation in clinical trials of SABR.
authors.affiliation: Division of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: J H
authors.initials: JH
authors.lastname: Chang
authors.affiliation: Division of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Gandhidasan
authors.affiliation: Princess Alexandra Hospital, Brisbane, Queensland, Australia.
authors.forename: R
authors.initials: R
authors.lastname: Finnigan
authors.affiliation: Royal North Shore Hospital, Sydney, New South Wales, Australia.
authors.forename: D
authors.initials: D
authors.lastname: Whalley
authors.affiliation: The William Buckland Radiotherapy Centre, Melbourne, Victoria, Australia.
authors.forename: R
authors.initials: R
authors.lastname: Nair
authors.affiliation: Department of Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Herschtal
authors.affiliation: Royal North Shore Hospital, Sydney, New South Wales, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Eade
authors.affiliation: Royal North Shore Hospital, Sydney, New South Wales, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Kneebone
authors.affiliation: The William Buckland Radiotherapy Centre, Melbourne, Victoria, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Ruben
authors.affiliation: Princess Alexandra Hospital, Brisbane, Queensland, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Foote
authors.affiliation: Division of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia. Electronic address: shankar.siva@petermac.org.
authors.forename: S
authors.initials: S
authors.lastname: Siva
mesh_terms: D000368:Aged; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D016634:Radiosurgery / Q000379:methods*; D012189:Retrospective Studies; D013120:Spinal Cord Neoplasms / Q000473:pathology / Q000532:radiotherapy*
keywords: Intensity-modulated radiotherapy; metastasis; radiosurgery; spine; stereotactic body radiotherapy