Clinical utility of prostate-specific antigen mass ratio for prediction of prostate cancer detection on a repeated prostate biopsy

To assess the clinical utility of the prostate-specific antigen mass ratio (PSA- MR), a newly developed PSA derivative, simply defined as the (i) PSA density (PSA-D) multiplied by the plasma volume or (ii) total PSA amount in circulation per prostate volume, for predicting prostate cancer (PCa) among men undergoing repeated prostate biopsy (PBx).Patients (n = 286), who underwent a repeated PBx, were analyzed. The various parameters associated with PCa detection were noted in each patient. PSA-MR was also calculated.PCa was detected in 63 (22.0%) of 286 patients. PSA-MR was the independent predictor in the univariate- and multivariate logistic regression analyses (OR = 3.448, p = 0.001 and OR = 13.430, p = 0.033, respectively). A nomogram that incorporated PSA-MR was considered a useful tool (predictive accuracy: 79.2%, 95% CI: 0.726-0.858, p < 0.001). Furthermore, a nomogram that incorporated PSA-MR would have avoided 59.6% of unnecessary repeated PBx. The predictive accuracy of PSA-MR was also superior to that of PSA or PSA-D (p = 0.013 and 0.009, respectively).PSA-MR was an independent predictor, and its consideration would have avoided 59.6% of unnecessary repeated PBx for PCa detection. PSA-MR was also superior than PSA or PSA-D. Our results support the use of PSA-MR to facilitate counseling with patients after a negative initial PBx, and use of PSA-MR might reduce further unnecessary biopsies.