PROSTATE-SPECIFIC ANTIGEN DENSITY - A MEANS TO ENHANCE DETECTION OF PROSTATE-CANCER

The ability of serum prostate-specific antigen (PSA) and PSA density ( PSAD) to distinguish patients with prostate cancer from those with ben ign diseases of the prostate was assessed in 495 men. Ah men were eval uated with PSA determination, digital rectal examination (DRE), transr ectal ultrasonography (TRUS) and ultrasound-guided prostatic biopsies. PSA was analysed by the polyclonal (Yang) assay. Prostate volume was estimated from TRUS. PSAD was determined by dividing the serum PSA by the volume of the prostate. Prostatic biopsies identified cancer in 24 6 of the 495 patients (49.7%). The entire group was divided into 6 sub groups according to PSA level at presentation. Cancer and noncancer pa tients were compared in each subgroup with respect to the values of PS A, prostate volume and PSAD. For the entire group of patients, there w as no statistically significant advantage, for PSAD over serum PSA alo ne, in distinguishing between benign and malignant prostatic condition s. However, when patients were stratified according to PSA level, PSAD was statistically significantly superior to serum PSA alone in the de tection of prostate cancer for PSA values in the intermediate range (2 .6-30 ng/ml). This analysis with respect to the DRE and TRUS results s howed PSAD to be superior to PSA when both examinations are normal. Ou r results demonstrate that the influence of PSAD level on cancer detec tion proportionally increases as the PSAD value increases. Curves cons tructed from the incidence of prostate cancer according to PSAD values may be useful to select patients with intermediate levels of serum PS A, and normal DRE and TRUS for prostatic biopsies.