Percentage of free prostate-specific antigen (PSA) is a useful method in deciding to perform prostate biopsy with higher core numbers in patients with low PSA cut-off values.

The aim of this study was to evaluate the predictive role of percentage of free prostate-specific antigen (%fPSA) cut-points in prostate cancer (PCa) detection in patients with total PSA (tPSA) levels between 2.5 ng/mL and 10.0 ng/mL. In total, 1321 consecutive initial transrectal ultrasound (TRUS)-guided 12-core biopsies performed between 2005 and 2011 were evaluated retrospectively. Benign pathologies, high-grade prostatic intraepithelial neoplasia, and atypical small acinary proliferations were categorized as noncancerous (benign), and prostate adenocarcinomas were categorized as cancerous (malignant). The patients were categorized according to: Catalona's published %fPSA categories (<10%, 10-15%, 15-20%, 20-25%, or > 25%); digital rectal examination (DRE) results [benign (negative) or suspicious of malignancy (positive)]. There was a significant relationship between the %fPSA cut-points and detection of PCa in DRE-negative patients. The presence of a 10% cut-point increased the probability of PCa threefold. The %fPSA was significantly more related to PCa than the tPSA value in receiver operating characteristic (ROC) curve analyses (p = 0.001). Based on our findings, a lower %fPSA, especially <10%, is an important parameter when deciding whether to perform a biopsy on patients with a tPSA between 2.5 ng/mL and 10 ng/mL.