Tests to check your prostate health

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Tests to check your prostate health
BMJ Group, Monday 13 October 2008
Article history
The symptoms of an enlarged prostate can look like the symptoms of more serious conditions, such as prostate cancer. Your doctor may do some, or all, of these tests to find out for certain what's causing your symptoms. But for some of them you will need to see a specialist in a hospital.

Medical history

Your doctor may ask you general questions about your health and past illnesses, operations or treatments you've had (doctors call this your 'medical history'). Your doctor may then ask you about any problems you're having urinating, such as a weak stream of urine or having to get up at night to go to the toilet.

Your doctor will also ask you about any drugs you are taking, both prescriptions and over-the-counter drugs. This is because some drugs (such as antidepressants) can affect the way your bladder works. Next, your doctor will probably do a physical examination of your prostate. This is called a digital rectal examination (DRE).

Digital rectal examination (DRE)

Because your prostate is inside your body, your doctor can't see it. But he or she can feel it by putting a gloved and lubricated finger into your back passage (rectum). Your doctor can feel if your prostate is enlarged, has lumps on it, or feels strange in some other way. Your doctor should be able to feel lumps that are bigger than half an inch (around 1.5 centimetres). However, smaller lumps are easy to miss.

This exam can be a little bit uncomfortable, and some men find it embarrassing. But it's not usually painful and only takes a few minutes. Your doctor may also feel the lower part of your stomach to see if he or she can feel your bladder. If your doctor can feel your bladder, it may not be emptying properly.

Prostate-specific antigen (PSA) blood test

This test measures the amount of a substance called prostate-specific antigen, or PSA, in your blood. Your test results will show your level of PSA in a measurement of nanograms (ng) per millilitre (ml) of blood.

Your prostate makes PSA to keep your semen in a liquid state. (Semen is the name given to your sperm and the fluid they are carried in.) When cancer is present, more PSA may seep from your prostate into your blood. But you can also have a high level of PSA if you have an enlarged prostate.

There are a lot of unanswered questions about PSA testing. When it's used with a digital rectal examination, it can help detect prostate cancer. But it cannot tell you for certain if you have cancer. It can only tell you what your chances of having it are.

For example, most men have a PSA level under 4 nanograms per millilitre of blood. If your level is above 4, but less than 10, your chances of having prostate cancer are about 1 in 4. The higher your PSA level is, the greater your chances of having prostate cancer. If your level goes above 10, your chances of having prostate cancer are more than 1 in 2.

But there are many problems with the test. For example, PSA levels go up naturally as you get older, even if your prostate is normal. And other things, such as sexual activity, can also push it up. So the results of PSA tests are not always clear. If your PSA level is raised, your doctor may advise you to have other tests to find out what has made it go up.

Another problem is that doctors don't always know what to do if they find a high PSA level. We don't know if finding and treating prostate cancer early will improve your chances of surviving it.[1] The research isn't clear. Also, some tumours that are found by a PSA test are not a problem. They do not cause any symptoms or health problems if they're left just where they are and are never treated.

Urine and blood tests

You will be asked to urinate into a special container and this sample will then be checked for infection or blood. Having an infection can cause you to need to urinate a lot, just like BPH can. Blood in the urine (called haematuria) can be a sign of bladder cancer, but it's also common in men with an enlarged prostate. If you have blood in your urine, you should see a urologist. A urologist is a doctor who deals with the male sex organs and the urinary tract (the tubes that carry urine from your bladder to outside your body) in men and women.

Your doctor may also test your urine or your blood to see how much creatinine they contain. Creatinine is a protein that's made naturally by your body. The amount of creatinine in your urine or blood shows how your kidneys are working. Your kidneys get rid of waste products from your blood and make urine. If you have symptoms of an enlarged prostate, your chances of having kidney problems are slightly raised.[2] Although these problems are rare, your doctor will want to catch any problems early.

Prostate biopsy

This is the main test doctors use to find out for certain whether you have prostate cancer. Your doctor will use a special needle to remove tiny bits from your prostate. The needle is either gently pushed through the wall of your back passage into your prostate, or put into the skin between your scrotum (the sac that holds your testicles) and your anus (the opening with which you empty your bowels).

The needle is guided by a special device called an ultrasound probe. A biopsy is not usually painful, but you may feel a sharp prick, even if you are given a local anaesthetic (painkiller) to numb the area. Your doctor will give you antibiotics to prevent you getting an infection after the test.

A doctor then looks at the tissue from the biopsy under a microscope. If cancer cells are present, the more abnormal these cells look compared to healthy prostate cells, the more aggressive and likely to spread the cancer may be.

Peak or maximum urinary flow rate test

This test measures how quickly or slowly you are passing urine. All you have to do is urinate into a special device. You then get a score, called a Qmax rating, which tells you the fastest speed that your urine flows. A low Qmax rating suggests your urine flow is restricted and you may have an enlarged prostate.

Post-void residual test

This test measures the amount of urine left in your bladder after you've finished urinating. The test is very straightforward and painless. After you've passed urine, a scanner is passed over your lower abdomen where your bladder is. If the scanner shows there's urine left in your bladder, it may mean you have an enlarged prostate. You may also be at higher risk of getting an infection in your bladder.

Pressure-flow test

This test measures the force (or pressure) in your bladder when you urinate. It's used to see if there's any blockage in your bladder. A small tube is inserted into your bladder through your penis to measure the pressure. This can be uncomfortable, which is why this test is usually used only in patients who can't be diagnosed with other tests.

Ultrasound scan

Your doctor may recommend that you have an ultrasound scan of your lower body. This is similar to the scan given to pregnant women to see images of their developing baby. The ultrasound can show if your prostate gland is enlarged or abnormal, and whether any urine is left in your bladder after you've urinated. The scan is not painful or unpleasant.

Transrectal ultrasound scan (TRUS)

For this test, a special probe is put into your back passage. The probe is a solid rod about the size of a finger with an ultrasound device at the end. It creates pictures of your prostate and the surrounding area. If your doctor thinks there is a chance you have cancer, a small sample of tissue may also be taken during the scan. Your doctor will then look at this tissue under a microscope to see if it contains any cancer cells.

References

National Institute of Diabetes and Digestive and Kidney Diseases Prostate Enlargement: Benign Prostatic Hyperplasia NIH Publication No. 02-3012

Thorpe A, Neal D. Benign prostate hyperplasia. Lancet. 2003; 361: 1359-1367.

Glossary

rectum

The rectum is the last 15 to 20 centimetres (six to eight inches) of the large intestine, ending with the anus (where you empty your bowels from).

bladder

Your bladder is the hollow organ at the top of your pelvis that stores urine. It is similar to a balloon, only with stronger walls. It fills up with urine until you go to the toilet.

ultrasound probe