Diagnosing prostate cancer
If you have symptoms that could be caused by prostate cancer, your GP will discuss the pros and cons of the tests with you. Your doctor is likely to:
- ask for a urine sample to check for infection
- take a blood sample to test your level of prostate-specific antigen (PSA)
- examine your prostate (digital rectal examination)
Prostate-specific antigen (PSA) testing
Prostate-specific antigen (PSA) is a protein produced by the prostate gland. All men have a small amount of PSA in their blood, and it increases with age. Prostate cancer can increase the production of PSA. A prostate-specific antigen (PSA) test looks for raised levels of PSA in the blood and may be able to detect prostate cancer in its early stages.
However, PSA testing is not a specific test for prostate cancer. Most men who have prostate cancer will not have a raised PSA level. More than 65% of men with a raised PSA level will not have cancer, as PSA levels rises in all men as they get older.
For more information on PSA testing, see the 'Prostate cancer - screening' section.
Digital rectal examination
The next step is a digital rectal examination (DRE). This can be done by your GP.
During a DRE, your GP will insert a finger into your rectum. The rectum is close to your prostate gland, so your GP can check to feel if the surface of the gland has changed. This will feel a little uncomfortable but it should not be painful.
Prostate cancer can make the gland hard and bumpy. However, in some cases, the cancer causes no changes to the gland and a DRE may not be able to detect the cancer.
DRE is also useful in ruling out benign prostatic hyperplasia, as this causes the gland to feel firm and smooth.
Want to know more?
- The Prostate Cancer Charity: DRE.
Your GP will assess the risk of you possibly having prostate cancer based on a number of factors, including your PSA levels, the results of your DRE and associated risk factors, such as age, family history and ethnic group. If it is felt that you are at risk, you will be referred to a hospital to discuss the options of further tests.
The most commonly used test is known as a transrectal ultrasound-guided biopsy (TRUS).
During a TRUS biopsy, an ultrasound probe (a machine that uses sound waves to build up a picture of the inside of your body) is put into your rectum. This lets the doctor or specialist nurse see exactly where to pass a fine needle through the wall of your rectum to take small samples of tissue from your prostate (biopsy).
The procedure can be uncomfortable and sometimes painful. You may be given a local anaesthetic to minimise any discomfort. As with any procedure, there may be complications, including bleeding and infection.
Although it is much more reliable than a PSA test, a biopsy may miss up to 20% of cancers. Therefore, you may need to have another biopsy if your symptoms persist, or your PSA level continues to rise.
Want to know more?
- The Prostate Cancer Charity: biopsy.
The samples of tissue from the biopsy are then studied in a laboratory. If cancerous cells are found, they can be studied further to see how quickly the cancer will spread.
This measure is known as the Gleason score. The lower the score, the less likely the cancer will spread.
- A Gleason score of 6 or less means the cancer is unlikely to spread.
- A Gleason score of 7 means that there is a moderate chance of the cancer spreading.
- A Gleason score of 8 or above means there is a significant chance that the cancer will spread.
If there is a significant chance that the cancer has spread from your prostate to other parts of the body, further tests may be recommended.
Two tests that are commonly used are:
- Magnetic resonance imaging (MRI) or computed tomography (CT) scan – these scans build up a detailed picture of the inside of your body. They can be used to check if the cancer has spread beyond the prostate to the surrounding tissue.
- An isotope bone scan – this test uses a small amount of radiation dye injected into the vein, which gradually moves through the bloodstream and collects in the parts of the bone where there are any abnormalities. An isotope bone scan can tell if the cancer has spread to your bones.