PSA (Prostate Specific Antigen) Blood Test

Prostate cancer is the most common cancer to affect men in the UK and every year over 11,000 men die of prostate cancer. Finding cancer early improves your chances of being successfully treated, but also increases your risk of being treated for a cancer which is not aggressive and may not have affected your lifespan. The side-effects of prostate cancer treatment can include erectile dysfunction and urinary incontinence which can have a big impact on your quality of life. This is why prostate screening in the UK is a controversial subject. 

 

Prostate specific antigen (PSA) is a marker which can be used in screening for prostate cancer, as well as in its treatment. 

Whilst the PSA test can help to detect prostate cancer earlier, it has several shortcomings when used as a screening test. We encourage you to do as much research as possible and be aware of the risks and benefits of taking a PSA test before buying this test. 

Besides being elevated by prostate cancer, PSA levels can also be raised as a result of urinary tract infection, or even certain activities such as recent ejaculation and some forms of exercise. This means that there is a risk of PSA being elevated when no cancer is present (a false positive). For every 100 men with a high PSA result, approximately 75 of them will have a false positive result, and 25 will have a true positive (i.e. they will have prostate cancer). Currently the most reliable way of working out whether someone has a true positive or a false positive is by performing a prostate biopsy. Because the PSA test has a high false positive rate many of these prostate biopsies will prove to be unnecessary. However, the use of MRI scans before a biopsy means that unnecessary biopsies are in decline. 

 

You should also be aware that PSA tests can cause false negative results. This means that the PSA result is in the normal range but the person has underlying prostate cancer. PSA levels can remain normal in the early stages of prostate cancer, providing false reassurance. If we test 100 men with prostate cancer then approximately 15 of them would have a normal PSA result (a false negative).

In some cases prostate cancer grows very slowly and may never cause symptoms or shorten lifespan. A significant proportion of the men who receive a true positive result may undergo surgery that they did not need.

If you have any symptoms such as the need to urinate frequently, difficulty in starting or stopping the flow of urine, pain during sex, or any other urinary symptoms then please see your doctor for a full examination. Do not attempt to diagnose yourself with a PSA test.