title: A prognostic index model for predicting overall survival in patients with metastatic castration-resistant prostate cancer treated with abiraterone acetate after docetaxel.
abstract: BACKGROUND
  Few prognostic models for overall survival (OS) are available for patients with metastatic castration-resistant prostate cancer (mCRPC) treated with recently approved agents. We developed a prognostic index model using readily available clinical and laboratory factors from a phase III trial of abiraterone acetate (hereafter abiraterone) in combination with prednisone in post-docetaxel mCRPC.
  
  
  METHODS
  Baseline data were available from 762 patients treated with abiraterone-prednisone. Factors were assessed for association with OS through a univariate Cox model and used in a multivariate Cox model with a stepwise procedure to identify those of significance. Data were validated using an independent, external, population-based cohort.
  
  
  RESULTS
  Six risk factors individually associated with poor prognosis were included in the final model: lactate dehydrogenase > upper limit of normal (ULN) [hazard ratio (HR) = 2.31], Eastern Cooperative Oncology Group performance status of 2 (HR = 2.19), presence of liver metastases (HR = 2.00), albumin ≤4 g/dl (HR = 1.54), alkaline phosphatase > ULN (HR = 1.38) and time from start of initial androgen-deprivation therapy to start of treatment ≤36 months (HR = 1.30). Patients were categorized into good (n = 369, 46%), intermediate (n = 321, 40%) and poor (n = 107, 13%) prognosis groups based on the number of risk factors and relative HRs. The C-index was 0.70 ± 0.014. The model was validated by the external dataset (n = 286).
  
  
  CONCLUSIONS
  This analysis identified six factors used to model survival in mCRPC and categorized patients into three distinct risk groups. Prognostic stratification with this model could assist clinical practice decisions for follow-up and monitoring, and may aid in clinical trial design.
  
  
  BACKGROUND
  NCT00638690.
authors.affiliation: Department of Medical Oncology, BC Cancer Agency, Vancouver, Canada kchi@bccancer.bc.ca.
authors.forename: K N
authors.initials: KN
authors.lastname: Chi
authors.affiliation: Janssen Research & Development, San Diego.
authors.forename: T
authors.initials: T
authors.lastname: Kheoh
authors.affiliation: Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco.
authors.forename: C J
authors.initials: CJ
authors.lastname: Ryan
authors.affiliation: Janssen Research & Development, Menlo Park.
authors.forename: A
authors.initials: A
authors.lastname: Molina
authors.affiliation: Department of Solid Tumor Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston.
authors.forename: J
authors.initials: J
authors.lastname: Bellmunt
authors.affiliation: Comprehensive Cancer Centers of Nevada, Las Vegas.
authors.forename: N J
authors.initials: NJ
authors.lastname: Vogelzang
authors.affiliation: Department of Oncology and Internal Medicine, Memorial Sloan Kettering Cancer Center and Weill Cornell Medical College, New York, USA.
authors.forename: D E
authors.initials: DE
authors.lastname: Rathkopf
authors.affiliation: Groupe Uro-Genitologie, Institut Gustave Roussy, University of Paris Sud, Villejuif, France.
authors.forename: K
authors.initials: K
authors.lastname: Fizazi
authors.affiliation: Department of Solid Tumor Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston.
authors.forename: P W
authors.initials: PW
authors.lastname: Kantoff
authors.affiliation: Johnson & Johnson Medical China, Shanghai, China.
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Medical Oncology, BC Cancer Agency, Vancouver, Canada.
authors.forename: A A
authors.initials: AA
authors.lastname: Azad
authors.affiliation: Department of Medical Oncology, BC Cancer Agency, Vancouver, Canada.
authors.forename: B J
authors.initials: BJ
authors.lastname: Eigl
authors.affiliation: Tom Baker Cancer Center and University of Calgary, Calgary.
authors.forename: D Y C
authors.initials: DY
authors.lastname: Heng
authors.affiliation: Department of Medical Oncology, Princess Margaret Hospital and University of Toronto, Toronto, Canada.
authors.forename: A M
authors.initials: AM
authors.lastname: Joshua
authors.affiliation: Drug Development Unit, Division of Cancer Therapeutics/Clinical Studies, The Institute for Cancer Research and Royal Marsden Hospital, Sutton, UK.
authors.forename: J S
authors.initials: JS
authors.lastname: de Bono
authors.affiliation: Genitourinary Oncology Service, Memorial Sloan Kettering Cancer Center and Weill Cornell Medical College, New York, USA.
authors.forename: H I
authors.initials: HI
authors.lastname: Scher
mesh_terms: D000069501:Abiraterone Acetate / Q000009:adverse effects / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D018572:Disease-Free Survival; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D011241:Prednisone / Q000009:adverse effects / Q000627:therapeutic use*; D016016:Proportional Hazards Models; D064129:Prostatic Neoplasms, Castration-Resistant / Q000188:drug therapy*
chemical_list: D000970:Antineoplastic Agents; D000069501:Abiraterone Acetate; D011241:Prednisone
keywords: abiraterone acetate; castration-resistant prostate cancer; prognostic; risk; survival