title: A critical assessment of post-prostatectomy prostate specific antigen doubling time acceleration--is it stable?
abstract: OBJECTIVE
  We examined a retrospective cohort of patients with biochemical recurrence after prostatectomy to determine whether prostate specific antigen doubling time would remain stable with time. We also examined the relationship between other clinical parameters and the change in prostate specific antigen doubling time.
  
  
  METHODS
  We retrospectively reviewed the prostate cancer database from 1989 to 2008 to identify patients treated with radical prostatectomy for prostate cancer who experienced prostate specific antigen recurrence. Of the 2,237 patients identified 329 had biochemical recurrence. Prostate specific antigen doubling time was calculated at each visit and linear regression of prostate specific antigen doubling time with time was fit. Rate of change in prostate specific antigen doubling time was defined as the slope of the least squares regression line.
  
  
  RESULTS
  Median followup was 5 years (range 0.2 to 18). High Gleason score and local recurrence within 5 years were significantly associated with shorter 2-year prostate specific antigen doubling time and a decreased rate of change in doubling time (p = 0.0096, 0.0119, 0.0195 and 0.0258, respectively). Metastasis within 5 years was significantly associated with shorter 2 and 5-year doubling time (p = 0.0006 and 0.0014, respectively). Using all prostate specific antigen values within 5 years of initial biochemical recurrence yielded an overall median prostate specific antigen doubling time of 52.8 months (range 5.4 to 100.0). The median rate of change in doubling time was -1.05 (range -64.7 to 27.0). Median time to metastasis after biochemical recurrence was 12.9 years.
  
  
  CONCLUSIONS
  Median prostate specific antigen doubling time decreases with time. This may influence the decision to offer secondary therapy to patients with biochemical recurrence sooner since initial prostate specific antigen doubling time is long and may not accurately reflect the biological nature of the disease.
authors.affiliation: Department of Urology, Indiana University School of Medicine, Indianapolis, Indiana, USA. hoosiers20@gmail.com
authors.forename: K Clint
authors.initials: KC
authors.lastname: Cary
authors.forename: Cynthia S
authors.initials: CS
authors.lastname: Johnson
authors.forename: Liang
authors.initials: L
authors.lastname: Cheng
authors.forename: Michael O
authors.initials: MO
authors.lastname: Koch
mesh_terms: D000328:Adult; D000368:Aged; D006801:Humans; D016018:Least-Squares Analysis; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009362:Neoplasm Metastasis; D011184:Postoperative Period; D017430:Prostate-Specific Antigen / Q000493:pharmacokinetics*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood* / Q000473:pathology / Q000601:surgery; D012189:Retrospective Studies
chemical_list: D017430:Prostate-Specific Antigen