title: Outcomes and toxicity for hypofractionated and single-fraction image-guided stereotactic radiosurgery for sarcomas metastasizing to the spine.
abstract: OBJECTIVE
  Conventional radiation treatment (20-40 Gy in 5-20 fractions, 2-5 Gy per fraction) for sarcoma metastatic to the spine provides subtherapeutic doses, resulting in poor durable local control (LC) (50%-77% at 1 year). Hypofractionated (HF) and/or single-fraction (SF) image-guided stereotactic radiosurgery (IG-SRS) may provide a more effective means of managing these lesions.
  
  
  METHODS
  Patients with pathologically proven high-grade sarcoma metastatic to the spine treated with HF and SF IG-SRS were included. LC and overall survival (OS) were analyzed by the use of Kaplan-Meier statistics. Univariate and multivariate analyses were performed by the use of Cox regression with competing-risks analysis; all confidence intervals are 95%. Toxicities were assessed according to Common Terminology Criteria for Adverse Events, version 4.0.
  
  
  RESULTS
  From May 2005 to November 11, 2012, 88 patients with 120 discrete metastases received HF (3-6 fractions; median dose, 28.5 Gy; n=52, 43.3%) or SF IG-SRS (median dose, 24 Gy; n=68, 56.7%). The median follow-up time was 12.3 months. At 12 months, LC was 87.9% (confidence interval [CI], 81.3%-94.5%), OS was 60.6% (CI, 49.6%-71.6%), and median survival was 16.9 months. SF IG-SRS demonstrated superior LC to HF IG-SRS (12-month LC of 90.8% [CI, 83%-98.6%] vs 84.1% [CI, 72.9%-95.3%] P=.007) and retained significance on multivariate analysis (P=.030, hazard ratio 0.345; CI, 0.132-0.901]. Treatment was well tolerated, with 1% acute grade 3 toxicity, 4.5% chronic grade 3 toxicity, and no grade >3 toxicities.
  
  
  CONCLUSIONS
  In the largest series of metastatic sarcoma to the spine to date, IG-SRS provides excellent LC in the setting of an aggressive disease with low radiation sensitivity and poor prognosis. Single-fraction IG-SRS is associated with the highest rates of LC with minimal toxicity.
authors.affiliation: Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Folkert
authors.affiliation: Department of Neurosurgery, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Bilsky
authors.affiliation: Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Ashlyn K
authors.initials: AK
authors.lastname: Tom
authors.affiliation: Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Jung Hun
authors.initials: JH
authors.lastname: Oh
authors.affiliation: Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Kaled M
authors.initials: KM
authors.lastname: Alektiar
authors.affiliation: Department of Neurosurgery, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: Ilya
authors.initials: I
authors.lastname: Laufer
authors.affiliation: Department of Medical Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York.
authors.forename: William D
authors.initials: WD
authors.lastname: Tap
authors.affiliation: Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York. Electronic address: yamadaj@mskcc.org.
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Yamada
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D011379:Prognosis; D016016:Proportional Hazards Models; D011832:Radiation Injuries / Q000175:diagnosis; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D011879:Radiotherapy Dosage; D012509:Sarcoma / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D013125:Spinal Neoplasms / Q000401:mortality / Q000556:secondary* / Q000601:surgery*; D016896:Treatment Outcome