PSA-DT, also known as PSA Doubling Time or PSA Velocity is the time it takes for a PSA value to double (i.e. 2 to 4, 4 to 8, 8 to 16). In the situation when a PSA reappears after a radical prostatectomy the PSA-DT serves as a predictor of future metastatic disease.
Okotie et al did a retrospective analysis of the bone scans performed on 128 men with T2 – T4 prostate cancer who experienced a biochemical recurrence after a radical prostatectomy (mean time from the RP to biochemical failure was 28 months). He found that of the 31 men who had a PSA-DT that was less then 6 months, 26% (8 of 31) had a positive bone scan. Of the 62 men with a PSA-DT greater then 6 months only 3% (2 of 62) had a positive bone scan.
Two additional retrospective analyses of patients with Stage T1b-T3 prostate cancer who underwent radical prostatectomy at The Johns Hopkins Hospital were reported in 1999 by Pound et al (N=1997) and in 2005 by Freedland et al (N=5096). Both of these studies had large samples and both of these analyses clearly confirmed that men with shorter PSA-DT where more likely to have metastatic disease .
Clearly, the less time the PSA takes to double after a radical prostatectomy, the more likely that metastatic disease will be found.
1. Freedland SJ, Humphreys EB, Mangold LA, et al. Risk of prostate cancer-specific mortality following biochemical recurrence after radical prostatectomy. JAMA. 2005;294:433-439.
2. Pound CR, Partin AW, Eisenberger MA, et al. Natural history of progression after PSA elevation following radical prostatectomy. JAMA. 1999;281:1591-1597.
3. Okotie OT, Aronson WJ, Wieder JA, et al. Predictors of metastatic disease in men with biochemical failure following radical prostatectomy. J Urol. 2004;171:2260-2264.
Joel T. Nowak, MA, MSW