Routine estimation of prostate specific antigen prior to clinic attendance in patients with symptoms of bladder outlet obstruction.

We report the use of serum prostate specific antigen (PSA) estimations prior to clinic attendance in 234 patients referred with symptoms of bladder outlet obstruction to a general urology clinic. Ninety-three patients with PSA levels > 10 ng/ml were seen earlier than planned and offered transurethral resection or transrectal biopsy of the prostate gland. Forty-six patients (49%) proved to have carcinoma of the prostate, compared with 10 of 141 (7%) patients who had PSA values < 10 ng/ml. With a decision value of 10 ng/ml, the sensitivity for detecting carcinoma was 82% and specificity 73.5%. Using a decision value of 7 ng/ml improved the sensitivity to 95% without significantly affecting the specificity (70%). Twenty-four patients with prostatic cancer had bone metastases; the sensitivity of PSA for predicting a positive bone scan using a decision value of 25 ng/ml was 92%, but the specificity was only 31%.