title: Prediction of survival after surgery due to skeletal metastases in the extremities.
abstract: OBJECTIVE
  The purpose of this study was to develop a prognostic model for predicting survival of patients undergoing surgery owing to metastatic bone disease (MBD) in the appendicular skeleton.
  
  
  METHODS
  We included a historical cohort of 130 consecutive patients (mean age 64 years, 30 to 85; 76 females/54 males) who underwent joint arthroplasty surgery (140 procedures) owing to MBD in the appendicular skeleton during the period between January 2003 and December 2008. Primary cancer, pre-operative haemoglobin, fracture versus impending fracture, Karnofsky score, visceral metastases, multiple bony metastases and American Society of Anaesthesiologist's score were included into a series of logistic regression models. The outcome was the survival status at three, six and 12 months respectively. Results were internally validated based on 1000 cross-validations and reported as time-dependent area under the receiver-operating characteristic curves (AUC) for predictions of outcome.
  
  
  RESULTS
  The predictive scores obtained showed AUC values of 79.1% (95% confidence intervals (CI) 65.6 to 89.6), 80.9% (95% CI 70.3 to 90.84) and 85.1% (95% CI 73.5 to 93.9) at three, six and 12 months.
  
  
  CONCLUSIONS
  In conclusion, we have presented and internally validated a model for predicting survival after surgery owing to MBD in the appendicular skeleton. The model is the first, to our knowledge, built solely on material from patients who only had surgery in the appendicular skeleton.
  
  
  CONCLUSIONS
  Applying this prognostic model will help determine whether the patients' anticipated survival makes it reasonable to subject them to extensive reconstructive surgery for which there may be an extended period of rehabilitation. Cite this article: Bone Joint J 2016;98-B:271-7.
authors: Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen Ø, Denmark.
authors: M S
authors: MS
authors: Sørensen
authors: Øster Farimagsgade 5, 1014 Copenhagen K, Denmark.
authors: T A
authors: TA
authors: Gerds
authors: Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen Ø, Denmark.
authors: K
authors: K
authors: Hindsø
authors: Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen Ø, Denmark.
authors: M M
authors: MM
authors: Petersen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019643:Arthroplasty, Replacement / Q000401:mortality*; D001859:Bone Neoplasms / Q000401:mortality* / Q000556:secondary / Q000601:surgery; D003718:Denmark / Q000453:epidemiology; D005121:Extremities; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012307:Risk Factors
keywords: Metastases; Survival prediction; Validation