PSA is a simple blood test used to detect prostate cancer in the early stages of the disease, at a time when treatment is most effective. The test is not perfect, as other benign conditions may cause an abnormal PSA and not all prostate cancers diagnosed require treatment. This has led to some controversy as to whether PSA screening is a good idea. The following information may help you decide whether PSA testing is right for you. We encourage discussion with a specialist or your GP before making a decision.
What is PSA?
PSA stands for Prostate Specific Antigen. This is an enzyme made exclusively by the prostate gland. Its function is to keep sperm liquid in the ejaculate, preventing clumping allowing the sperm to swim freely. Small amounts of PSA leak into the bloodstream where it can be detected by a blood test.
What level of PSA is abnormal?
There is no specific cut-off for an abnormal PSA. PSA levels rise naturally with age and benign enlargement of the prostate, so this needs to be taken into account when performing the test. In general a PSA > 2.5 ng/ml is considered abnormal in a man in his 50’s, whereas a PSA >4.0 ng/ml is considered abnormal in a man in his 60’s.
What does an abnormal PSA mean?
An increased PSA may be caused by prostate cancer, benign enlargement of the prostate or an infection within the prostate. Transient elevation of the PSA may also be caused by a urine infection, sexual activity or direct pressure to the prostate (prostate examination, riding a horse or bicycle etc). We would always recommend a second PSA test if the first is abnormal to confirm this. Generally speaking, a PSA level between 4.0 – 10.0 ng/ml confers roughly a 25% chance of a diagnosis of prostate cancer.
Will the PSA test pick up all prostate cancers?
The PSA test is very sensitive and will pick up about 90% of prostate cancers. However some more aggressive prostate cancers do not make PSA (as the cells no longer resemble prostate cells) and may be quite advanced even with a normal PSA level. As such, we would recommend a digital rectal exam (DRE) is performed by your doctor to feel for any cancerous lumps on your prostate, in conjunction with a PSA test.
Should I have a biopsy if my PSA is abnormal?
A prostate biopsyis the only way to diagnose prostate cancer, or differentiate from a benign cause for an abnormal PSA. Unless you are elderly or have multiple medical problems (and unlikely to live at least 10 years) you will be recommended to have a biopsy.
Does PSA testing save lives?
There is little doubt that PSA testing has saved lives. Since PSA testing became available in the late 1980’s, prostate cancer mortality in Australia has fallen from 34.5 to 30.6 deaths per 100,000 men to 2010. Five year relative survival has increased from 58.2% to 92.0% over the same time (Cancer Australia, Australian Government).
Is there evidence for mass population PSA screening?
While few would argue that PSA testing has saved lives, controversy exists as to whether mass population screening of all men aged 50-70 years would do more harm than good. There are currently two ongoing randomised controlled trials attempting to answer this question. In Europe, the European Randomised Study of Screening for Prostate Cancer (ERSPC) trial showed a 20% reduction in prostate cancer mortality in the screening group with a median of 9 years follow up. In contrast to this, the American Prostate, Lung, Colorectal and Ovary (PLCO) screening trial showed no difference in prostate cancer mortality, however data is complete only to 7 years follow up. While some have commented that the trials are contradictory, the ERSPC trial showed no difference at 7 years either – the results are very similar, but the end results are looking at two different snapshots of time. Given that prostate cancer is slow growing and can take up to 10-15 years to cause death, we would expect to see a wider difference in prostate cancer mortality between the screened and non-screened groups as time progresses and the cohorts mature. Having said that, the current evidence probably does not support widespread population based screening for all men aged 50-70 at present. This does not mean however, that screening is not beneficial for selected healthy men with a life expectancy >15 years.
Is there any harm with having a PSA test?
If your PSA test is abnormal, you may require a biopsy. Some men find this an uncomfortable test and there is a small risk of infection, which can sometimes be serious. Some men who are diagnosed with prostate cancer will undergo radical treatment (surgery or radiotherapy) may have problems with erections or continence following their treatment. To prevent this, we would recommend men diagnosed with low risk prostate cancer to undergo active surveillance rather than radical treatment, as they are unlikely to die from their prostate cancer and unwanted side effects may be avoided.
So should I have a PSA test?
Men who may benefit from a PSA test include:
- Those with a family history of prostate cancer (father or brother)
- Healthy men with a life expectancy >15 years
- Men willing to undergo a biopsy if the test is abnormal
- Men comfortable with surveillance if a low grade prostate cancer is diagnosed
- Men willing to undergo radical treatment if a more serious cancer is diagnosed
At what age should I start PSA testing if I want it?
There is increasing evidence that a one off PSA test at the age of 40 years will stratify your future risk of prostate cancer and determine whether or not you need PSA testing in the future.
Otherwise we would recommend PSA testing between 50 – 70 years.
The decision to undergo a PSA test is up to the individual after consideration of the available evidence. We recommend discussion with a specialist or your GP about the pros and cons before making a decision.