title: Creation of a Prognostic Index for Spine Metastasis to Stratify Survival in Patients Treated With Spinal Stereotactic Radiosurgery: Secondary Analysis of Mature Prospective Trials.
abstract: OBJECTIVE
  There exists uncertainty in the prognosis of patients following spinal metastasis treatment. We sought to create a scoring system that stratifies patients based on overall survival.
  
  
  METHODS
  Patients enrolled in 2 prospective trials investigating stereotactic spine radiation surgery (SSRS) for spinal metastasis with ≥ 3-year follow-up were analyzed. A multivariate Cox regression model was used to create a survival model. Pretreatment variables included were race, sex, age, performance status, tumor histology, extent of vertebrae involvement, previous therapy at the SSRS site, disease burden, and timing of diagnosis and metastasis. Four survival groups were generated based on the model-derived survival score.
  
  
  RESULTS
  Median follow-up in the 206 patients included in this analysis was 70 months (range: 37-133 months). Seven variables were selected: female sex (hazard ratio [HR] = 0.7, P=.02), Karnofsky performance score (HR = 0.8 per 10-point increase above 60, P = .007), previous surgery at the SSRS site (HR = 0.7, P=.02), previous radiation at the SSRS site (HR = 1.8, P=.001), the SSRS site as the only site of metastatic disease (HR = 0.5, P=.01), number of organ systems involved outside of bone (HR = 1.4 per involved system, P<.001), and >5 year interval from initial diagnosis to detection of spine metastasis (HR = 0.5, P < .001). The median survival among all patients was 25.5 months and was significantly different among survival groups (in group 1 [excellent prognosis], median survival was not reached; group 2 reached 32.4 months; group 3 reached 22.2 months; and group 4 [poor prognosis] reached 9.1 months; P < .001). Pretreatment symptom burden was significantly higher in the patient group with poor survival than in the group with excellent survival (all metrics, P < .05).
  
  
  CONCLUSIONS
  We developed the prognostic index for spinal metastases (PRISM) model, a new model that identified patient subgroups with poor and excellent prognoses.
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Chad
authors.initials: C
authors.lastname: Tang
authors.affiliation: Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Hess
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Bishop
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Hubert Y
authors.initials: HY
authors.lastname: Pan
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Eva N
authors.initials: EN
authors.lastname: Christensen
authors.affiliation: Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: James N
authors.initials: JN
authors.lastname: Yang
authors.affiliation: Department of Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Nizar
authors.initials: N
authors.lastname: Tannir
authors.affiliation: Department of Diagnostic Radiology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Behrang
authors.initials: B
authors.lastname: Amini
authors.affiliation: Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Claudio
authors.initials: C
authors.lastname: Tatsui
authors.affiliation: Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Laurence
authors.initials: L
authors.lastname: Rhines
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas.
authors.forename: Paul
authors.initials: P
authors.lastname: Brown
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas. Electronic address: ajghia@mdanderson.org.
authors.forename: Amol
authors.initials: A
authors.lastname: Ghia
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D010147:Pain Measurement; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D016634:Radiosurgery / Q000379:methods / Q000401:mortality*; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods / Q000401:mortality; D013125:Spinal Neoplasms / Q000401:mortality* / Q000556:secondary* / Q000601:surgery*; D016019:Survival Analysis; D013997:Time Factors; D055815:Young Adult