It is known that serum prostate specific antigen (PSA) in urinary retention due to benign prostatic hypertrophy (BPH) increase. To evaluate prognostic value of the ratio of serum PSA to γ-seminoprotein (P/S Ratio) for prostate cancer (PC) in patients with urinary retention, we have studied the P/S Ratio at the initial examination in 33 patients with untreated PC (10 with and 23 without urinary retention) and 193 patients with untreated BPH (38 with and 155 without urinary retention) histopathologically diagnosed at our hospital between January, 1992 and December, 1993.
The results were as follows:
1) The mean P/S ratio of PC patients was significantly higher than that of BPH patients in both groups with and without urinary retention.
2) When the cut off value of P/S Ratio was determined to be 1.35, the highest efficiency, 59.3% was obtained in the group without urinary retention. The sensitivity and specificity were 65.2% and 91.0%.
3) In the group with urinary retention, the efficiency was also the highest, 80.0% with a cut off value of 1.35. The sensitivity and specificity were 80.0% and 100%.
4) In all patients, the efficiency was 64.6%, the sensitivity was 69.7%, and the specificity was 92.7% with a cut off value of 1.35.
5) Positive rate of serum PSA in BPH patients with urinary retention was 47.4% and that in BPH patients without urinary retention was 17.4%. The mean P/S ratio of the BPH patients with urinary retention was significantly lower than that of BPH patients without urinary retention, which suggested that the serum free PSA increase in the former.
P/S Ratio is useful means of diagnosis for PC especially in patients with urinary retention.