title: Prostate Specific Antigen Working Group guidelines on prostate specific antigen doubling time.
abstract: OBJECTIVE
  Prostate specific antigen is a glycoprotein found almost exclusively in normal and neoplastic prostate cells. Prostate specific antigen doubling time, or the change in prostate specific antigen over time, has emerged as a useful predictive marker for assessing disease outcome in patients with prostate cancer. It is important to agree on definitions and values for the calculation of prostate specific antigen doubling time, and to develop a common approach to outcome analysis and reporting.
  
  
  METHODS
  In September 2006 a conference was held at the National Cancer Institute in Bethesda, Maryland to define these parameters and develop guidelines for their use.
  
  
  RESULTS
  The Prostate Specific Antigen Working Group defined criteria regarding prostate specific antigen doubling time including the calculation of prostate specific antigen doubling time, evidence to support prostate specific antigen doubling time as a predictive factor in the setting of biochemical recurrence and the use of prostate specific antigen doubling time as a stratification factor in clinical trials.
  
  
  CONCLUSIONS
  We propose that investigators calculate prostate specific antigen doubling time before enrolling patients in clinical studies and calculate it as an additional measurement of therapeutic activity. We believe we have developed practical guidelines for the calculation of prostate specific antigen doubling time and its use as a measurement of prognosis and outcome. Furthermore, the use of common standards for prostate specific antigen doubling time in clinical trials is important as we determine which treatments should progress to randomized trials in which "hard" end points such as survival will be used.
authors.affiliation: Medical Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892, USA.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Arlen
authors.forename: Fernando
authors.initials: F
authors.lastname: Bianco
authors.forename: William L
authors.initials: WL
authors.lastname: Dahut
authors.forename: Anthony
authors.initials: A
authors.lastname: D'Amico
authors.forename: William D
authors.initials: WD
authors.lastname: Figg
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Freedland
authors.forename: James L
authors.initials: JL
authors.lastname: Gulley
authors.forename: Philip W
authors.initials: PW
authors.lastname: Kantoff
authors.forename: Michael W
authors.initials: MW
authors.lastname: Kattan
authors.forename: Andrew
authors.initials: A
authors.lastname: Lee
authors.forename: Meredith M
authors.initials: MM
authors.lastname: Regan
authors.forename: Oliver
authors.initials: O
authors.lastname: Sartor
mesh_terms: D015415:Biomarkers / Q000097:blood; D006801:Humans; D008297:Male; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood*; D013997:Time Factors
chemical_list: D015415:Biomarkers; D017430:Prostate-Specific Antigen