The value of the measurement of serum prostate specific antigen in patients with benign prostatic hyperplasia and untreated prostate cancer.

Serum prostate specific antigen (PSA) levels were measured in 139 patients with benign prostatic hyperplasia (BPH) and in 88 patients with prostate cancer who were managed by deferred treatment. Acute urinary retention and large prostate glands tended to be associated with high PSA levels, but at levels greater than 10 ng/ml there was a significant risk of carcinoma being found on subsequent histological examination. The risk of progression of untreated prostate cancer was associated with levels of PSA greater than 20 ng/ml and with a high rate of change of PSA level. The value of measuring PSA in these patients is discussed.