Prostate specific antigen doubling time after radical prostatectomy: Effect of neoadjuvant androgen deprivation therapy

Purpose: We determined the predictors of prostate specific antigen (PSA) do ubling time in patients with relapse after radical prostatectomy as well as whether PSA doubling time is shorter in those treated versus not treated w ith neoadjuvant androgen deprivation therapy. Materials and Methods: We calculated PSA doubling time in 204 patients with PSA relapse after radical prostatectomy who were or were not treated with neoadjuvant androgen deprivation therapy. Analysis of covariance was used t o determine the effect of clinical and pathological parameters on PSA doubl ing time, and the proportion of variability explained by these parameters. Results: Clinical stage, and combined clinical stage and margin status, cli nical stage and androgen deprivation therapy status, androgen deprivation t herapy status and time to PSA relapse, and androgen deprivation therapy sta tus and pretreatment PSA were significant predictors of PSA doubling time. Any variable or combination of variables explained up to only 21% of PSA do ubling time variability. When stratified by pretreatment PSA, clinical stag e and biopsy grade, the difference in doubling times in patients treated wi th or without neoadjuvant androgen deprivation therapy was significant only for 4.1 to 10 ng./ml. PSA. In this group mean doubling time plus or minus standard deviation in patients receiving neoadjuvant androgen deprivation t herapy and those treated only with radical prostatectomy was 7.6 +/- 1.0 an d 15.4 +/- 2.6 months, respectively. Conclusions: Our study indicates that it is difficult to predict PSA doubli ng time in an individual. The small proportion of variability in PSA doubli ng time explained by the interaction of androgen deprivation therapy status and other variables indicates that these factors are not clinically signif icant.