The PSA test

taken from Small Gland, Big Problem 4th Edition
by Professor Roger Kirby, Health Press 2011

PSA, prostate-specific antigen, is a protein-like substance that occurs in abundance in the fluid within the prostate. Testing blood samples to determine the amount of PSA (a ‘PSA test’) is central to the early detection and selection of the most effective treatment for prostate cancer. Monitoring a man’s PSA level is also extremely helpful once therapy has been started, as it can indicate how effectively treatment is working. If the PSA is rising in spite of treatment, second-line therapies such as oestrogens or chemotherapy with, for example, Taxotere (docetaxel) may be in order.

The growth of cancer cells in the prostate disrupts the structure and organization of the tissue. PSA inside the prostate is able to leak into the nearby blood vessels more readily than it does in a healthy prostate. As a result, the amount of PSA in the blood increases, which is why measurement of PSA in a blood sample can help to diagnose prostate cancer