title: Progression-free survival as a predictor of overall survival in men with castrate-resistant prostate cancer.
abstract: OBJECTIVE
  To explore whether progression-free survival (PFS) or biochemical PFS can be used as a predictor of overall survival (OS) and to investigate the dependence between PFS and OS in men with castrate-resistant prostate cancer.
  
  
  METHODS
  Data from nine Cancer and Leukemia Group B trials that enrolled 1,296 men from 1991 to 2004 were pooled. Men were eligible if they had prostate cancer that had progressed during androgen deprivation therapy and did not receive prior treatment with chemotherapy, immunotherapy, or other nonhormonal therapy. Landmark analyses of PFS at 3 and 6 months from randomization/registration were performed to minimize lead time bias. The proportional hazards model was used to assess the significance effect of PFS rate at 3 and at 6 months in predicting OS. In addition, biochemical progression using the definitions of Prostate-Specific Antigen Working Group (PSAW) Criteria PSAWG1 and PSAWG2 were analyzed as time-dependent covariates in predicting OS.
  
  
  RESULTS
  The median survival time among men who experienced progression at 3 months was 9.2 months (95% CI, 8.0 to 10.0 months) compared with 17.8 months in men who did not experience progression at 3 months (95% CI, 16.2 to 20.4 months; P < .0001). Compared with men who did not progress at 3 and at 6 months, the adjusted hazard ratios for death were 2.0 (95% CI, 1.7 to 2.4; P < .001) and 1.9 (95% CI, 1.6 to 2.4; P < .001) for men who experienced progression at 3 and 6 months, respectively. In addition, biochemical progression at 3 months predicted OS. The association between PFS and OS was 0.30 (95% confidence limits = 0.26, 0.32).
  
  
  CONCLUSIONS
  PFS at 3 and 6 months and biochemical progression at 3 months predict OS. These observations require prospective validation.
authors.affiliation: Department of Biostatistics and Bioinformatics, Duke University Medical Center, 2424 Erwin Rd, Durham, NC 27705, USA. susan.halabi@duke.edu
authors.forename: Susan
authors.initials: S
authors.lastname: Halabi
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Vogelzang
authors.forename: San-San
authors.initials: SS
authors.lastname: Ou
authors.forename: Kouros
authors.initials: K
authors.lastname: Owzar
authors.forename: Laura
authors.initials: L
authors.lastname: Archer
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Small
mesh_terms: D002986:Clinical Trials as Topic; D018450:Disease Progression; D018572:Disease-Free Survival; D006801:Humans; D008297:Male; D011379:Prognosis; D016016:Proportional Hazards Models; D017430:Prostate-Specific Antigen / Q000032:analysis; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D017430:Prostate-Specific Antigen