Does early prostate-specific antigen doubling time (ePSADT) after radical prostatectomy, calculated using PSA values from the first detectable until the first recurrence value, correlate with standard PSADT? A report from the Shared Equal Access Regional Cancer Hospital Database Group

OBJECTIVE To determine if prostate-specific antigen doubling time (PSADT), calculated from the first detectable PSA level after radical prostatectomy (RP) to the first PSA level of >= 0.2 ng/mL (early PSADT or ePSADT), correlated with 'standard' PSADT (henceforth PSADT) calculated using values >= 0.2 ng/mL, as a short PSADT following biochemical recurrence (BCR) after RP portends a poor prognosis and poor response to salvage treatment but this is based upon PSADT calculated using PSA values of >= 0.2 ng/mL. PATIENTS AND METHODS We used Spearman's correlation to determine the correlation between ePSADT and PSADT among 157 men in the Shared Equal Access Regional Cancer Hospital database who underwent RP between 1988 and 2005 and had a calculable ePSADT and PSADT. We systematically examined ePSADT thresholds and their positive and negative predictive values (PPV and NPV, respectively), to predict aggressive recurrences (PSADT of < 9 months). RESULTS ePSADT was significantly, though poorly, correlated with PSADT (r = 0.30, P < 0.001). ePSADT more accurately predicted PSADT among men with a long ePSADT. Of men with an ePSADT of >= 20 or >= 15 months, the NPV for an aggressive recurrence was 98% and 93%, respectively. However, among men with an ePSADT of < 3 months, the PPV for aggressive recurrence was only 39%. CONCLUSIONS Although ePSADT and PSADT were significantly related, the overall correlation was poor. This was highlighted by the finding that only 39% of men with the shortest ePSADT (< 3 months) had a PSADT of < 9 months. However, a long ePSADT correlated well with a long PSADT and is thus useful in identifying men at low risk for prostate cancer-specific mortality very early in their BCR.