PSA divergence. A new parameter for the accurate longitudinal assessment of prostatic disease

Prostate-specific antigen (PSA) and the various parameters derived utilizing this marker have increased our ability to diagnose early prostatic disease; however, their accuracy in identifying the etiology of the disease remains somewhat limited. We propose a new PSA derivative, termed "PSA divergence" (PSADI), defined as the change in serum PSA over time (years) divided by the change in prostatic volume over time (years), to more accurately distinguish benign, premalignant, and malignant prostatic diseases. In this study, we evaluated 160 subjects with a PSA >4.0 ng/ml who were found by transrectal ultrasound-guided biopsy (TRUS) to have either benign prostatic hyperplasia or prostatic intraepithelial neoplasia. These men were followed at 6 or 12 months with serial PSA, digital rectal exam (DRE), and TRUS with rebiopsy. Data analysis demonstrated a statistically significant (p < 0.05) correlation between PSADI and each final pathologic outcome, suggesting that PSADI is useful in distinguishing among intraepithelial neoplasia and benign and malignant prostatic disease.