Serum-to-Urinary Prostate Specific Antigen Ratio: Its Impact in Distinguishing Prostate Cancer When Serum Prostate Specific Antigen Level is 4 to 10 ng./ml.

ABSTRACTPurpose: Benign prostatic hyperplasia (BPH) was shown to be associated with high concentrations of urinary prostate specific antigen (PSA). We investigated the serum-to-urinary PSA ratio in patients undergoing prostate biopsy to assess its efficacy in enhancing serum PSA specificity in the detection of prostate carcinoma.Materials and Methods: From November 1995 through January 1996 consecutive patients undergoing prostate biopsy were prospectively included in the study. Serum and urine PSA levels were measured at our laboratory with the Tandem-R† †Hybritech, Inc., San Diego, California. assay. Samples were drawn 24 hours before prostate biopsy and at a distance from prostatic manipulation or ejaculation.Results: We studied 73 patients with BPH and 57 with prostate cancer. Differences between BPH and prostate cancer were statistically significant considering serum PSA or serum-to-urinary PSA ratios. In the 50 patients with a serum PSA of 4.0 to 10.0 ng./ml. (35 with BPH and 15 with prostate cancer...