title: Development and validation of a pretreatment prognostic index to predict death and lung metastases in extremity osteosarcoma.
abstract: BACKGROUND
  To develop a prognostic index to predict the 5-year overall survival (OS) and 5-year lung metastasis-free survival (LMFS) of patients with extremity osteosarcoma at the time of diagnosis.
  
  
  METHODS
  We retrospectively evaluated 454 patients with extremity osteosarcoma at our center from 2005 to 2013. The cohort was randomly divided into training and validation sets. The association of potential risk factors with OS and LMFS was assessed by Cox proportional hazards analysis in the training set, and a prognostic index was created according to scores that were proportional to a regression coefficient for each factor. This prognostic index was assessed in the validation set.
  
  
  RESULTS
  For the 5-year OS, 5 independent prognostic factors were identified: tumor size, Enneking stage, pretreatment platelet, alkaline phosphatase(ALP), and neutrophils. The multivariate Cox model identified tumor size, pretreatment platelets, ALP, and neutrophils as associated with the 5-year LMFS. A prognostic index for death and lung metastases was calculated. Three risk groups were defined for each survival point: low, intermediate, and high risk for the 5-year OS; low, intermediate, and high risk for the 5-year LMFS. The C statistic for the 5-year OS was 0.723 in the training set and 0.710 in the validation set. The C statistic for the 5-year LMFS was 0.661 and 0.693 respectively.
  
  
  CONCLUSIONS
  This prognostic index is based on routine tests and characteristics of extremity osteosarcoma patients and is a useful predictor of OS and lung metastases. This index could be applied to clinical practice and trials for individualized risk-adapted therapies.
authors.affiliation: Musculoskeletal Oncology Center, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.affiliation: Musculoskeletal Oncology Center, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Tu
authors.affiliation: Musculoskeletal Oncology Center, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong, China.
authors.forename: Junqiang
authors.initials: J
authors.lastname: Yin
authors.affiliation: Musculoskeletal Oncology Center, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong, China.
authors.forename: Changye
authors.initials: C
authors.lastname: Zou
authors.affiliation: Musculoskeletal Oncology Center, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Wang
authors.affiliation: Musculoskeletal Oncology Center, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Huang
authors.affiliation: Musculoskeletal Oncology Center, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong, China.
authors.forename: Xianbiao
authors.initials: X
authors.lastname: Xie
authors.affiliation: Musculoskeletal Oncology Center, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong, China.
authors.forename: Jingnan
authors.initials: J
authors.lastname: Shen
mesh_terms: D000293:Adolescent; D000328:Adult; D000469:Alkaline Phosphatase / Q000097:blood; D014408:Biomarkers, Tumor / Q000097:blood; D001859:Bone Neoplasms / Q000097:blood / Q000401:mortality* / Q000473:pathology* / Q000628:therapy; D016009:Chi-Square Distribution; D002648:Child; D002681:China; D003661:Decision Support Techniques; D018572:Disease-Free Survival; D005121:Extremities; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007958:Leukocyte Count; D008175:Lung Neoplasms / Q000097:blood / Q000401:mortality* / Q000556:secondary* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D009504:Neutrophils / Q000473:pathology; D012516:Osteosarcoma / Q000097:blood / Q000401:mortality* / Q000556:secondary* / Q000628:therapy; D010976:Platelet Count; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D047368:Tumor Burden; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D000469:Alkaline Phosphatase
keywords: lung metastases; osteosarcoma; pretreatment prognostic index; survival outcomes