A Critical Evaluation of Prostate Specific Antigen Parameter Responses to Manipulation According to Prostatic Histology

Abstract

Introduction: The degree of increase in prostate specific antigen (PSA) forms after prostatic manipulation may differ depending on histology. We sought to critically evaluate this hypothesis and to examine possible clinical implications. Methods: A series of 198 men referred for transrectal ultrasound-guided biopsy on clinical grounds had free (fPSA) and total PSA (tPSA) levels determined before undergoing biopsy and 30 min after biopsy. A subset of 100 men had the same analysis immediately before and 30 min after digital rectal examination (DRE). Geometric mean ratios and two-sample t tests compared the change in levels of fPSA, PSA, the ratio of fPSA to tPSA (f/t PSA), fPSA density, and PSA density after manipulation to prostatic histology. Results: After undergoing biopsies, 57 men (29%) received a diagnosis of prostate cancer. The biopsy significantly altered all parameters. The degree of change was less in the malignant group for all parameters, although this only approached statistical significance for PSA and PSA density levles (p = 0.159 and p = 0.170, respectively). In the DRE group, the PSA changes were similar, although the cancer patients tended to release slightly less PSA forms (PSA, p = 0.376; fPSA, p = 0.657; f/t PSA, p = 0.396). Conclusion: PSA release and PSA parameter alteration after manipulation differ in the neoplastic prostate. The subtlety of change after DRE currently limits clinical application.