title: RTOG 0631 phase 2/3 study of image guided stereotactic radiosurgery for localized (1-3) spine metastases: phase 2 results.
abstract: OBJECTIVE
  The phase 2 component of Radiation Therapy Oncology Group (RTOG) 0631 assessed the feasibility and safety of spine radiosurgery (SRS) for localized spine metastases in a cooperative group setting.
  
  
  METHODS
  Patients with 1-3 spine metastasis with a Numerical Rating Pain Scale (NRPS) score ≥5 received 16 Gy single fraction SRS. The primary endpoint was SRS feasibility: image guidance radiation therapy (IGRT) targeting accuracy ≤2 mm, target volume coverage >90% of prescription dose, maintaining spinal cord dose constraints (10 Gy to ≤10% of the cord volume from 5-6 mm above to 5-6 mm below the target or absolute spinal cord volume <0.35 cc) and other normal tissue dose constraints. A feasibility success rate <70% was considered unacceptable for continuation of the phase 3 component. Based on the 1-sample exact binomial test with α = 0.10 (1-sided), 41 patients were required. Acute toxicity was assessed using the National Cancer Institute Common Toxicity Criteria for Adverse Events, version 3.0.
  
  
  RESULTS
  Sixty-five institutions were credentialed with spine phantom dosimetry and IGRT compliance. Forty-six patients were accrued, and 44 were eligible. There were 4 cervical, 21 thoracic, and 19 lumbar sites. Median NRPS was 7 at presentation. Final pretreatment rapid review was approved in 100%. Accuracy of image guided SRS targeting was in compliance with the protocol in 95%. The target coverage and spinal cord dose constraint were in accordance with the protocol requirements in 100% and 97%. Overall compliance for other normal tissue constraints was per protocol in 74%. There were no cases of grade 4-5 acute treatment-related toxicity.
  
  
  CONCLUSIONS
  The phase 2 results demonstrate the feasibility and accurate use of SRS to treat spinal metastases, with rigorous quality control, in a cooperative group setting. The planned RTOG 0631 phase 3 component will proceed to compare pain relief and quality of life between SRS and external beam radiation therapy.
authors.affiliation: Henry Ford Hospital, Detroit, Michigan. Electronic address: sryu1@hfhs.org.
authors.forename: Samuel
authors.initials: S
authors.lastname: Ryu
authors.affiliation: RTOG Statistical Center, Philadelphia, Pennsylvania.
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Pugh
authors.affiliation: University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Gerszten
authors.affiliation: Duke University Medical Center, Durham, North Carolina.
authors.forename: Fang-Fang
authors.initials: FF
authors.lastname: Yin
authors.affiliation: University of Texas Southwestern, Dallas, Texas.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Timmerman
authors.affiliation: Huntsman Cancer Center, University of Utah, Salt Lake City, Utah.
authors.forename: Ying J
authors.initials: YJ
authors.lastname: Hitchcock
authors.affiliation: Henry Ford Hospital, Detroit, Michigan.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Movsas
authors.affiliation: Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel.
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Kanner
authors.affiliation: H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida.
authors.forename: Lawrence B
authors.initials: LB
authors.lastname: Berk
authors.affiliation: University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: David S
authors.initials: DS
authors.lastname: Followill
authors.affiliation: Boston Medical Center Minority-Based Community Clinical Oncology Program, Boston, Massachusetts.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Kachnic
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000009:adverse effects* / Q000379:methods*; D013125:Spinal Neoplasms / Q000453:epidemiology / Q000556:secondary / Q000601:surgery*; D025321:Surgery, Computer-Assisted / Q000009:adverse effects* / Q000379:methods*