The usefulness of prostate-specific antigen and prostatic acid phosphatase in clinical practice.

A comparative study was performed on the usefulness of prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) in control subjects (69), benign prostatic hypertrophy (BPH) patients (150), and patients with prostatic carcinoma (113) in a urology department. We establish, as others, the greater clinical sensitivity of PSA and its effectiveness as a prognostic tool in the evaluation of prostatic cancer therapy and in the early detection of residual tumor following radical prostatectomy. However, patients are admitted to our department with more severe and complicated benign prostatic pathology and urinary dysfunctions, which decreases the specificity of the PSA test to 30% (N = 2.7 ng/ml). A cutoff threshold of 50 ng/ml becomes necessary to maintain a 90% positive predictive value. The combination of PSA sensitivity (96%) and PAP specificity (95%) enabled a better definition of the high-risk subpopulation among noncancer patients and, in addition, was a help for differential diagnosis, confirmation of advanced stages of prostatic cancer, and selection of low-stage prostatic cancer candidates undergoing radical prostatectomy. Routine serum PSA measurements in the population of patients consulting a urology department will no doubt bring about a new approach to the management of prostate cancer.