Poor Agreement of Prostate Specific Antigen Doubling Times Calculated Using Ultrasensitive Versus Standard Prostate Specific Antigen Values: Important Impact on Risk Assessment

Purpose: In men with biochemical recurrence after radical prostatectomy, a rapid prostate specific antigen doubling time is associated with adverse outcomes, and is often used to guide the type and timing of salvage therapy. It is unknown whether prostate specific antigen doubling time calculated in the ultrasensitive range (prostate specific antigen less than 0.2 ng/ml) accurately reflects measures performed in the traditional range (prostate specific antigen greater than 0.2 ng/ml).Materials and Methods: We studied 394 men in a national disease registry of men with prostate cancer (CaPSURE™) who underwent radical prostatectomy, experienced biochemical failure, and had prostate specific antigen doubling time assessed using ultrasensitive and traditional prostate specific antigen values. Agreement between these measurements was assessed using Cohen's kappa score.Results: Median ultrasensitive prostate specific antigen doubling time was 11.9 months (IQR 6–29) and median traditional prostate specific antige...