PSA: The Prostate Test

Winter 1999 CSANews Issue 31  |  Posted date : Mar 01, 2007.Back to list

Prostatic Specific Antigen (PSA) is a protein produced by the prostate gland. The use of PSA, which is measured with a blood test, has "taken off" in the last decade. PSA is now one of the common blood tests ordered by physicians in Canada, and is ordered primarily for the detection and follow-up of prostate cancer. The majority of physicians agree that PSA is a useful test for the work-up of men with overt symptoms related to the urinary system such as difficult or frequent urination. It is also an excellent test for the monitoring of patients who already have prostate cancer. Where controversy exists is in the use of PSA as a screening tool in men with no urinary symptoms. This is an issue that has yet to be worked out. PSA elevations can occur in other conditions, such as benign enlargement of the prostate and prostatitis, an inflammation of the prostate. PSA screening, therefore, will pick up men who have no cancer at all. As well, a proportion of men have cancer without an elevation of the PSA. We're not even certain that the early detection of prostate cancer actually translates to the useful prolongation of life and quality of life. Some new data coming out of the U.S., where PSA screening is recommended, suggest that the death rate from prostate cancer is dropping...so in fact, cancer survival may yet start being an argument for PSA screening. Refinements of PSA, such as PSA adjusted ranges and free to total fractionations of PSA will improve our ability to pick up on early cancer without unnecessarily investigating patients without cancer. Another concept of PSA velocity where we follow the PSA over time, looking for a rate of rise in PSA, may help us detect early cancers. Many doctors now believe that PSA is indispensable in following patients with prostate cancer and urological diseases. With the addition of counselling regarding lifestyle, diet, the consumption of soy protein and the antioxidants vitamin E and selenium, PSA and rectal exams are a good idea for men over 50, for men over 40 of African-American descent, or for men with a history of prostate cancer in their family. As with most tests, this one should be done on the foundation of an informed discussion with the urologist or physician.