Prostate specific antigen: an opinion on its value to the radiologist.

Screening for prostate cancer is controversial. There is currently enormous pressure from the public and media to test men for early prostate cancer, in a manner similar to the screening of women for breast cancer. Unfortunately, however, the two cancers do not behave in a similar biological manner; breast cancer screening has been shown to reduce mortality, but prostate cancer screening has not yet been proven to reduce mortality. Prostate-specific antigen (PSA) is currently the best single test for prostate cancer diagnosis, but it cannot identify whether the detected cancer will cause clinically significant disease. PSA can be used as an aid to the diagnosis, staging, prognosis and follow-up of patients with prostate cancer, and its use has transformed the diagnosis of cancer and has markedly improved the detection of organ-confined prostate cancer in Europe and North America. PSA is, however, an imperfect diagnostic marker, and a variety of approaches have been investigated in recent years to improve its specificity in the diagnosis of prostate cancer. These new approaches have been developed by urologists, radiologists and biochemists, and can be confusing for the clinician without special knowledge in this field. This article aims to review current knowledge of PSA from the viewpoint of the radiologist.