Your GP consultation and the PSA Test

If you have concerns

You should visit your GP. At your appointment the doctor may give you a Digital Rectal Examination (or DRE). 

The DRE examination

Although not a completely reliable test for prostate cancer, it is a simple way that a doctor can check your prostate. It is done by feeling it using a gloved finger in the back passage. This only takes a few seconds and generally may cause only a little discomfort. If any abnormalities are felt, it may be a sign of a problem. A simple blood test called a PSA test may also be suggested.

What is the PSA test? 

This is a blood test that will give you and your GP an indication of a possible problem with the prostate. The PSA blood test is not primarily a test for prostate cancer but is simply a measure of the health of your prostate. At present it is the best simple test we have.

PSA measures the level of Prostate Specific Antigen, a protein found in the prostate secreted mainly in the blood. The blood sample is normally taken at the GP surgery and is then sent away for analysis and comes back within a week.

Most men (typically two out of three) who have raised PSA levels may turn out not to have prostate cancer. However, about one sixth of men with a ‘normal’ PSA may actually have some evidence of prostate cancer.

Pros and Cons of knowing your PSA level

Your GP should also tell you the benefits and limitations of the test. If, after considering these, you wish to have the test and you decide to go ahead, it is your right to have the test, as laid down by The Prostate Cancer Risk Management Programme (2016). It states:

“The PSA test is available free to any well man aged 50 and over who requests it”.

It also says:

“The man’s personal preferences are an important factor in the decision”.

If you decide to have a PSA test, you must ask your GP for it; you are entitled to it. Here are some simple facts to help you decide:

 

 

  • It may reassure you.
  • It can be an early indication of prostate problems.
  • It can find cancers earlier than is possible by a DRE alone.
  • It may lead to treatment at an early stage and provide a cure.

     But:

  • A raised PSA level may lead to invasive tests when you have no cancer.
  • A mildly elevated PSA could lead to a diagnosis of prostate cancer which may be harmless and never need treatment.

 

 

Note: Be aware that PSA readings may be raised if the blood sample is taken after vigorous exercise, if ejaculation has occurred in the previous 48 hours, or shortly after a DRE.

What does it tell me about my prostate?

Sometimes a raised PSA level can be a sign of prostate cancer. It can also often point to something less serious, such as an inflamed or infected prostate (prostatitis), or an enlargement of the prostate that often comes as men age. This is called Benign Prostatic Hyperplasia, or BPH (sometimes now called BPE, standing for benign prostate enlargement).

What is a normal reading? 

The older you are, the higher your PSA level is likely to be (whether or not you have prostate cancer), as PSA naturally seeps into the bloodstream with age. It is measured in nanograms per millilitre (ng/mL)*, and can range from less than 1ng/mL to readings in the 1000s. Readings from 1 to 4 (depending on age) are generally normal. A single reading is of little value, unless it is high (say over 10ng/mL).

* Note: PSA levels are sometimes reported as μg/L (microgrames per litre), but the resulting number is exactly the same.

What if my PSA is higher than normal?

If the reading is marginal (say 3–5 ng/mL), a repeat test should be requested, normally after a few weeks. This is because the rate at which the PSA level may be increasing (called PSA velocity or PSA doubling time) can be a more reliable indicator of the presence of prostate cancer than a one-off test result. Most leading urologists recommend that all men over 50 or at special risk know and monitor their PSA regularly, and action should be taken when any substantial increase is noted. Any increase above 0.5 – 0.75ng/mL in one year should be a warning signal. 

The chart below will give you the generally accepted guidelines.

   Age Normal Marginal High
  Under 50 less than 2.0 2.0–3.0 over 3.0
  Under 60 less than 3.0 3.0–4.0 over 4.0
  Under 70 less than 4.0 4.0–5.0 over 5.0
  70 and over less than 5.0 5.0–6.0 over 6.0

You may wish to visit www.cancerscreening.nhs.uk/prostate/prostate-booklet-text.pdf which gives further information on the benefits and disadvantages of the PSA test.

A particularly high reading (i.e. above 10ng/mL) is more likely to be an indication of the presence of cancer in the prostate rather than other causes, such as prostate enlargement or prostate infection.

If the PSA reading is high, if doubling time is abnormal or there are other indications, your GP should refer you to a urologist for further tests in order to determine if cancer is present. These tests are outlined in the next section.

Other tests your GP could arrange

Free-to-Total PSA (or Free and Bound PSA Ratio, or fPSA) 

PSA may be free (not bound to a protein), or bound. Research indicates that if more than 18% (i.e. 1.8) of PSA is free, there is less chance of having a high grade prostate cancer. So the lower the percentage, the higher the risk. Currently it is not widely used, but knowing this PSA ratio may help avoid further unnecessary invasive tests.

PCA3

This is a urine test that is obtained from a sample, taken immediately after the doctor has massaged your prostate, which releases prostate cells into the urine. It claims higher accuracy at diagnosing the disease and its degree of aggressiveness. The higher the score, the greater likelihood of prostate cancer. Currently this test is only available privately as NICE has concluded that it is insufficiently accurate.

Research is continuing to find other protein or genetic markers that can give a more precise diagnosis of prostate cancer and its aggressiveness. These need to be rigorously tested on a large number of men before they become nationally available. Details may be found under Trials for Prostate Cancer.