taken from Small Gland, Big Problem 4th Edition
by Professor Roger Kirby, Health Press 2011
Earlier detection, while the disease is still curable, is already a reality as a result of PSA testing. In the future, new tests or variations of existing tests will continue to improve the ability of doctors and surgeons to distinguish early prostate cancer from BPH. Recently, a new test for prostate cancer called the PCA3 (prostate cancer antigen 3) test has been described, and several others are in the pipeline.
PCA3 test. Unfortunately, the PSA test is not reliably specific for prostate cancer, so some men who have a biopsy based on their PSA result are found not to have cancer. A gene called PCA3 (‘prostate cancer antigen 3’) has been highlighted in the search for another, more specific, marker of prostate cancer, and early work shows that finding a man’s ‘PCA3 score’ may be helpful. Prostate cancer cells have higher numbers (or copies) of the PCA3 gene and, because prostate cells are shed into the urine, the levels can be measured in a urine sample (obtained after digital rectal examination). A specific molecular test is used that compares levels of PCA3 against a ‘background’ level. More research is needed before the true value of this test is known.
It also seems likely that tests will soon be developed that predict the behaviour of individual prostate cancers more accurately, which will make it easier for patients, their families and their doctors to decide which is the best treatment option.