Most men are worried about PSA test result particularly if it is raised; because the test is extensively used (or misused) to detect prostate cancer all over the world. In the UK it is not used as a screening tool as it is done in the USA. The internet is awash with information on prostate cancer and PSA testing; I typed the words ‘prostate cancer’ on google search and got staggering 26,800,000 results. Similarly for ‘PSA test’ there were 1,830,000 results and I am pretty sure these figures are increasing everyday. I think it is high time we take a look at this test and know about it a little more; and also allay the anxiety it creates in their mind.
First and the foremost to understand is that PSA is prostate specific and not prostate cancer specific. The rise in its level could be due to a number of causes such as sexual intercourse, infection in the prostate gland, enlargement of prostate or it could be simply age-related. In addition examination of the prostate, bicycle riding, biopsy on prostate, sexual, catheterization or instrumentation of urethra and some medications can also affect the PSA levels. It is important therefore that patients need to understand that PSA is not a diagnostic test.
PSA is a specific protein produced by the cells of the prostate gland, which is only present in men. It is normally present in the semen (ejaculate or sperm) and found in small quantities in blood. PSA liquefies semen (sperm) after ejaculation to enable sperm to swim into their destination. The results are reported as nannograms per milliliter (ng/ml). A nannograms is one billionth of a gram, which shows that it is present in a very tiny quantity in the blood. Most of the laboratories report PSA between 0-4ng/ml as normal level. However, if the prostate gland is affected by any of the above-mentioned conditions, the PSA is likely to leak outside the prostate gland and its blood levels start rising. On the contrary PSA less than 4 does not completely rule out prostate cancer.
The use of PSA as a screening test for prostate cancer, therefore, is controversial. There is no evidence to suggest that early detection of prostate cancer reduces mortality. But PSA provides valuable information in the monitoring treated and untreated prostate cancer patients. It is a common clinical practice to assess prostate through the rectal examination along with PSA test.
Men requesting PSA testing should be counselled about the test; the information it is likely to provide, especially its limitations; and that it is possible to have prostate cancer even if their PSA is within the ‘normal’ range. Most of the times it may be useful to repeat the test after an interval of 2-3 months.
Men undergoing PSA testing with the aim of detecting early prostate cancer should understand that early detection and treatment may be beneficial but it is still uncertain to know how the cancer behaves in the future in that individual.