Usefulness of free/total PSA ratio and PSA density in distinguishing benign prostatic hypertrophy from prostatic cancer

Objective: To investigate the clinical significance of the free-to-total prostate-specific antigen ratio (f/tPSA) and PSA density (PSAD) for prostate cancer detection in patients with intermediate tPSA levels (4-10 ng/ml). To establish a cutoff to discriminate between benign prostatic disease (BPH) and prostate cancer (CaP), avoiding unnecessary biopsies.

Methods: This prospective study included 136 men, aged between 54 and 85 (mean 70.6) years old. Urinary tract symptoms were present in these patients. Serum samples were obtained to measure tPSA, fPSA, and f/tPSA; digital rectal examination and transrectal ultrasound eight-sector biopsies were performed. Prostate volume was measured and PSAD calculated. The pathologic study, carried out in 113 patients, showed 82 with BPH and 31 with prostate cancer in various stages.

Results: There were no significant differences between patients with BPH and CaP when comparing tPSA, fPSA, f/tPSA or digital rectal examination. PSAD and prostate volume were significantly different in patients with BPH and CaP. With a sensitivity of 94% (78.5-99), the f/tPSA cutoff was 0.28 with a 11% (5.2-19.8) specificity. With a sensitivity of 96.2% (80.3-99.4) cutoff for PSAD was 0.109 and specificity 25% (15.5-36.6).

Conclusions: In patients whose tPSA level is between 4 and 10 ng/ml, f/tPSA has no advantages over tPSA measurement for early detection of prostate cancer. DPSA can improve specificities, without compromising the detection of CaP.