title: How do we estimate survival? External validation of a tool for survival estimation in patients with metastatic bone disease-decision analysis and comparison of three international patient populations.
abstract: BACKGROUND
  We recently developed a clinical decision support tool, capable of estimating the likelihood of survival at 3 and 12 months following surgery for patients with operable skeletal metastases. After making it publicly available on www.PATHFx.org , we attempted to externally validate it using independent, international data.
  
  
  METHODS
  We collected data from patients treated at 13 Italian orthopaedic oncology referral centers between 2010 and 2013, then applied to PATHFx, which generated a probability of survival at three and 12-months for each patient. We assessed accuracy using the area under the receiver-operating characteristic curve (AUC), clinical utility using Decision Curve Analysis (DCA), and compared the Italian patient data to the training set (United States) and first external validation set (Scandinavia).
  
  
  RESULTS
  The Italian dataset contained 287 records with at least 12 months follow-up information. The AUCs for the three-month and 12-month estimates was 0.80 and 0.77, respectively. There were missing data, including the surgeon's estimate of survival that was missing in the majority of records. Physiologically, Italian patients were similar to patients in the training and first validation sets. However notable differences were observed in the proportion of those surviving three and 12-months, suggesting differences in referral patterns and perhaps indications for surgery.
  
  
  CONCLUSIONS
  PATHFx was successfully validated in an Italian dataset containing missing data. This study demonstrates its broad applicability to European patients, even in centers with differing treatment philosophies from those previously studied.
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. piccioli.and@gmail.com.
authors.forename: Andrea
authors.initials: A
authors.lastname: Piccioli
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. msilviaspinelli@yahoo.it.
authors.forename: M Silvia
authors.initials: MS
authors.lastname: Spinelli
authors.affiliation: Department of Molecular Medicine and Surgery, Section of Orthopaedics and Sports Medicine, Karolinska University Hospital, Karolinska Institute, Stockholm, Sweden. jonathan.forsberg@ki.se.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Forsberg
authors.affiliation: Department of Molecular Medicine and Surgery, Section of Orthopaedics and Sports Medicine, Karolinska University Hospital, Karolinska Institute, Stockholm, Sweden. Rikard.wedin@karolinska.se.
authors.forename: Rikard
authors.initials: R
authors.lastname: Wedin
authors.affiliation: Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, USA. healeyj@mskcc.org.
authors.forename: John H
authors.initials: JH
authors.lastname: Healey
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. ippobs55@hotmail.it.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Ippolito
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. PrimoAndrea.Daolio@gpini.i.
authors.forename: Primo Andrea
authors.initials: PA
authors.lastname: Daolio
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. pietro.ruggieri@ior.it.
authors.forename: Pietro
authors.initials: P
authors.lastname: Ruggieri
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. giuliomac@tiscali.it.
authors.forename: Giulio
authors.initials: G
authors.lastname: Maccauro
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. alessandro.gasbarrini@ior.it.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Gasbarrini
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. biagini@ifo.it.
authors.forename: Roberto
authors.initials: R
authors.lastname: Biagini
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. raipiana@gmail.com.
authors.forename: Raimondo
authors.initials: R
authors.lastname: Piana
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. f.fazioli@istitutotumori.na.it.
authors.forename: Flavio
authors.initials: F
authors.lastname: Fazioli
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. alessandro.gasbarrini@ior.it.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Luzzati
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. dimartino.cbm@gmail.com.
authors.forename: Alberto
authors.initials: A
authors.lastname: Di Martino
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. fracesconicolosi@yahoo.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Nicolosi
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. camnasio.francesco@hsr.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Camnasio
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. mattilio51@gmail.com.
authors.forename: Michele Attilio
authors.initials: MA
authors.lastname: Rosa
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. campanaccid@gmail.com.
authors.forename: Domenico Andrea
authors.initials: DA
authors.lastname: Campanacci
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. denaro@unicampus.it.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Denaro
authors.affiliation: The Italian Orthopaedic Society Bone Metastasis Study Group, Via Nicola Martelli, 3, 00197, Rome, Italy. rodolfo.capanna@gmail.com.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Capanna
mesh_terms: D000368:Aged; D001859:Bone Neoplasms / Q000175:diagnosis / Q000401:mortality* / Q000556:secondary* / Q000628:therapy; D003661:Decision Support Techniques; D005260:Female; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D012372:ROC Curve; D015203:Reproducibility of Results; D012537:Scandinavian and Nordic Countries; D016019:Survival Analysis; D014481:United States