SERUM-TO-URINARY PROSTATE-SPECIFIC ANTIGEN RATIO - A POTENTIAL MEANS OF DISTINGUISHING BENIGN PROSTATIC HYPERPLASIA FROM PROSTATE-CANCER

Objective: High concentrations of serum prostate-specific antigen (PSA ) may be associated with the presence of benign prostatic hyperplasia or prostatitis. We investigated the serum-to-urinary PSA ratio in pati ents with or without prostate cancer to assess its efficacy in enhanci ng serum PSA specificity. Methods: Patients presenting abnormal findin gs in digital rectal examination or documented prostate carcinoma were prospectively included in the study. A control group, with no evidenc e of prostate disease, hospitalized in the same time interval was incl uded. Serum and urine PSA levels were measured in our laboratory with the Tandem R assay (Hybritech). Samples were drawn twice at 2-month in tervals (M1 and M3). Results: Sixty-eight patients were included in th e study divided into 27 cases of benign prostatic hyperplasia, 20 of p rostate carcinoma, 10 of prostatitis and 11 patients in the control gr oup. Serum and urine PSA levels were not correlated (r less than or eq ual to \0.1\). There was no significant difference in any group from M 1 to M3 as regards urinary PSA (p greater than or equal to 0.15). Inte rgroup comparison showed significantly (p less than or equal to 0.004) high urinary PSA (mean level +/- SEM 28.3 +/- 3.4 mu g/mmol creatinin e) only in the benign prostatic hyperplasia group, mean levels in the prostate carcinoma, prostatitis and control groups being 3.7 +/- 1.1, 11 +/- 2.9 and 5.2 +/- 0.9 mu g/mmol creatinine, respectively. Differe nces in urinary PSA levels between the confined prostate carcinoma and benign prostatic hyperplasia groups (p = 0.0008) were further increas ed when considering the serum-to-urinary PSA ratio (p = 0.0003). Concl usion: Our results suggest that the serum-to-urinary PSA ratio may be useful in distinguishing benign prostatic hyperplasia from prostate ca ncer.