title: Predictive model for survival in patients having repeat radiation treatment for painful bone metastases.
abstract: OBJECTIVE
  To establish a survival prediction model in the setting of a randomized trial of re-irradiation for painful bone metastases.
  
  
  METHODS
  Data were randomly divided into training and testing sets with an approximately 3:2 ratio. Baseline factors of gender, primary cancer site, KPS, worst-pain score and age were included with backward variable selection to derive a model using the training set. A partial score was assigned by dividing the value of each statistically significant regression coefficient by the smallest statistically significant regression coefficient. The survival prediction score (SPS) was obtained by adding together partial scores for the variables that were statistically significant. Three risk groups were modelled.
  
  
  RESULTS
  The training set included 460 patients and the testing set 351 patients. Only KPS and primary cancer site reached the 5%-significance level. Summing up the partial scores assigned to KPS (90-100, 0; 70-80, 1; 50-60, 2) and primary cancer site (breast, 0; prostate, 1.3; other, 2.6; lung, 3) totalled the SPS. The 1/3 and 2/3 percentiles of the SPS were 2 and 3.6. For the testing set, the median survival of the 3 groups was not reached, 11.3 (95% C.I. 8.5 - not reached) and 5.2 months (95% C.I. 3.7-6.5). The 3, 6 and 12 month survival rates for the worst group were 64.4% (95% C.I. 55.3-72.1%), 43.0% (95% C.I. 34.0-51.8%) and 19.7% (95% C.I. 12.4-28.1%) respectively, similar to that in the training set.
  
  
  CONCLUSIONS
  This survival prediction model will assist in choosing dose fractionation. We recommend a single 8 Gy in the worst group identified.
authors.affiliation: Sunnybrook Odette Cancer Centre, University of Toronto, Canada. Electronic address: Edward.Chow@sunnybrook.ca.
authors.forename: Edward
authors.initials: E
authors.lastname: Chow
authors.affiliation: NCIC Clinical Trials Group, Cancer Research Institute, Queen's University, Kingston, Canada.
authors.forename: Keyue
authors.initials: K
authors.lastname: Ding
authors.affiliation: NCIC Clinical Trials Group, Cancer Research Institute, Queen's University, Kingston, Canada.
authors.forename: Wendy R
authors.initials: WR
authors.lastname: Parulekar
authors.affiliation: Princess Margaret Cancer Centre, Radiation Medicine Program, Ontario Cancer Institute, University of Toronto, Canada.
authors.forename: Rebecca K S
authors.initials: RK
authors.lastname: Wong
authors.affiliation: Leiden University Medical Centre, Leiden and Radiotherapy Institute Friesland, Leeuwarden, Netherlands.
authors.forename: Yvette M
authors.initials: YM
authors.lastname: van der Linden
authors.affiliation: Royal Adelaide Hospital, University of Adelaide, Australia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Roos
authors.affiliation: Northwestern Medicine Central DuPage Hospital Cancer Center, Warrenville, USA.
authors.forename: William F
authors.initials: WF
authors.lastname: Hartsell
authors.affiliation: Mount Vernon Hospital Cancer Centre, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Hoskin
authors.affiliation: Tom Baker Cancer Centre, University of Calgary, Canada.
authors.forename: Jackson S Y
authors.initials: JS
authors.lastname: Wu
authors.affiliation: Centre Hospitalier Universitaire de Sherbrooke, Canada.
authors.forename: Abdenour
authors.initials: A
authors.lastname: Nabid
authors.affiliation: University Medical Center St Radboud, Nijmegen, Netherlands.
authors.forename: Jan Willem
authors.initials: JW
authors.lastname: Leer
authors.affiliation: Radiation Institute Stedendriehoek en Omstreken, Deventer, Netherlands.
authors.forename: Ernest
authors.initials: E
authors.lastname: Vonk
authors.affiliation: Christchurch Hospital, New Zealand.
authors.forename: Scott
authors.initials: S
authors.lastname: Babington
authors.affiliation: Akron City Hospital, Northeast Ohio Medical University, USA.
authors.forename: William F
authors.initials: WF
authors.lastname: Demas
authors.affiliation: NCIC Clinical Trials Group, Cancer Research Institute, Queen's University, Kingston, Canada.
authors.forename: Carolyn F
authors.initials: CF
authors.lastname: Wilson
authors.affiliation: Queen's University, Kingston, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Brundage
authors.affiliation: NCIC Clinical Trials Group, Cancer Research Institute, Queen's University, Kingston, Canada.
authors.forename: Liting
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Juravinski Hospital and Cancer Centre and McMaster University, Hamilton, Canada.
authors.forename: Ralph M
authors.initials: RM
authors.lastname: Meyer
mesh_terms: D000368:Aged; D001859:Bone Neoplasms / Q000401:mortality* / Q000532:radiotherapy* / Q000556:secondary; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic / Q000379:methods; D016019:Survival Analysis; D015996:Survival Rate
keywords: Bone metastases; Predictive model; Re-irradiation; Survival