Lack of value of radioimmunoassay for prostatic acid phosphatase as a screening test for prostatic cancer in patients with obstructive prostatic hyperplasia.

We examined the incidence of prostatic cancer in patients with an elevated radioimmunoassay for prostatic acid phosphatase and clinical benign prostatic hyperplasia on digital rectal examination. Of 295 patients screened with prostatic acid phosphatase tests 17 fulfilled the criteria of having an elevated prostatic acid phosphatase, clinically benign prostate and histological examination of the prostatectomy specimen. None of the 17 patients had histological evidence of prostatic cancer. The results confirm the predictions of mathematical models that prostatic acid phosphatase is of no practical value as a screening test for prostatic cancer in patients with clinical benign prostatic hyperplasia.