Prostate specific antigen
Prostate specific antigen (PSA) is a protein secreted by the acinar cells of the prostate and is highly specific forthe prostate. Serum PSA levels are useful for determining the extent of prostate cancer and assessing theresponse to therapy. However, it is NOT prostate cancer-specific, and other conditions such as benign prostatichyperplasia (BPH) or prostatitis can affect PSA levels. PSA is commonly used as a tool to detect prostatecancer, but its role in screening programmes is widely debated and controversial.
PSA has a half-life of 2.2 days. Where levels are increased by different benign conditions, the time to return tobaseline levels is variable. The common causes of an elevated PSA are: