Associates in Urology: Topics in Urology: About PSA

About PSA

A great deal of media attention has been focused recently on a blood test used in the detection and treatment of prostate cancer known as PSA. PSA, which stands for Prostate Specific Antigen is an enzyme produced by the cells lining the ducts of the prostate gland. Since this enzyme is only found in the prostate gland, it is highly specific for prostatic disorders. Although PSA has many potential applications, it still has only been approved by the FDA as a tool to follow men with previously diagnosed prostate cancer.

When used as a screening test for prostate cancer, it should be emphasized that the PSA can be elevated in the setting of a number of benign prostate conditions. Therefore, PSA should only be used to determine which patients would benefit from a biopsy. Only a prostate biopsy can determine the presence of prostate cancer.

Many different modalities are available to assess PSA, and they often give different values in the same individual. These different modalities include: PSA density (PSA in relation to the size of the prostate), free and total PSA ratio, and age specific PSA ranges. Although each of these methods of PSA analysis may increase the specificity of the test for cancer detection, appropriate normal ranges for each of these modalities remain controversial.

In conclusion, PSA is an invaluable component of the urologist's armamentarium both for the diagnosis and the treatment of prostate cancer. PSA serves as a guideline only. It can not be emphasized enough that the majority of patients with an elevated PSA have biopsy proven benign disease and NOT cancer.