title: An easy tool to predict survival in patients receiving radiation therapy for painful bone metastases.
abstract: OBJECTIVE
  Patients with bone metastases have a widely varying survival. A reliable estimation of survival is needed for appropriate treatment strategies. Our goal was to assess the value of simple prognostic factors, namely, patient and tumor characteristics, Karnofsky performance status (KPS), and patient-reported scores of pain and quality of life, to predict survival in patients with painful bone metastases.
  
  
  METHODS
  In the Dutch Bone Metastasis Study, 1157 patients were treated with radiation therapy for painful bone metastases. At randomization, physicians determined the KPS; patients rated general health on a visual analogue scale (VAS-gh), valuation of life on a verbal rating scale (VRS-vl) and pain intensity. To assess the predictive value of the variables, we used multivariate Cox proportional hazard analyses and C-statistics for discriminative value. Of the final model, calibration was assessed. External validation was performed on a dataset of 934 patients who were treated with radiation therapy for vertebral metastases.
  
  
  RESULTS
  Patients had mainly breast (39%), prostate (23%), or lung cancer (25%). After a maximum of 142 weeks' follow-up, 74% of patients had died. The best predictive model included sex, primary tumor, visceral metastases, KPS, VAS-gh, and VRS-vl (C-statistic = 0.72, 95% CI = 0.70-0.74). A reduced model, with only KPS and primary tumor, showed comparable discriminative capacity (C-statistic = 0.71, 95% CI = 0.69-0.72). External validation showed a C-statistic of 0.72 (95% CI = 0.70-0.73). Calibration of the derivation and the validation dataset showed underestimation of survival.
  
  
  CONCLUSIONS
  In predicting survival in patients with painful bone metastases, KPS combined with primary tumor was comparable to a more complex model. Considering the amount of variables in complex models and the additional burden on patients, the simple model is preferred for daily use. In addition, a risk table for survival is provided.
authors.affiliation: Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands. Electronic address: p.g.westhoff@umcutrecht.nl.
authors.forename: Paulien G
authors.initials: PG
authors.lastname: Westhoff
authors.affiliation: Department of Medical Oncology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Alexander
authors.initials: A
authors.lastname: de Graeff
authors.affiliation: Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Evelyn M
authors.initials: EM
authors.lastname: Monninkhof
authors.affiliation: Department of Orthopedic Surgery, Leiden University Medical Center, The Netherlands.
authors.forename: Laurens
authors.initials: L
authors.lastname: Bollen
authors.affiliation: Department of Orthopedic Surgery, Leiden University Medical Center, The Netherlands.
authors.forename: Sander P
authors.initials: SP
authors.lastname: Dijkstra
authors.affiliation: ARTI Institute for Radiation Oncology Arnhem, Arnhem, The Netherlands.
authors.forename: Elzbieta M
authors.initials: EM
authors.lastname: van der Steen-Banasik
authors.affiliation: Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Marco
authors.initials: M
authors.lastname: van Vulpen
authors.affiliation: Department of Radiotherapy, University Medical Center Nijmegen, Nijmegen, The Netherlands.
authors.forename: Jan Willem H
authors.initials: JW
authors.lastname: Leer
authors.affiliation: Department of Clinical Oncology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Corrie A
authors.initials: CA
authors.lastname: Marijnen
authors.affiliation: Department of Clinical Oncology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Yvette M
authors.initials: YM
authors.lastname: van der Linden
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000401:mortality* / Q000532:radiotherapy / Q000556:secondary*; D001943:Breast Neoplasms; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017567:Karnofsky Performance Status; D008175:Lung Neoplasms; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000532:radiotherapy; D010147:Pain Measurement; D016016:Proportional Hazards Models; D011471:Prostatic Neoplasms; D011788:Quality of Life; D012737:Sex Factors; D016019:Survival Analysis