Prostate cancer - Diagnosing prostate cancer

If you have symptoms that could be caused by prostate cancer, you should visit your GP.

There is no single, definitive test for prostate cancer, so your GP will discuss the pros and cons of the various tests with you to try to avoid unnecessary anxiety.

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)

PSA testing

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, and so a PSA test looks for raised levels of PSA in the blood that may be a sign of the condition 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 rise in all men as they get older.

Read more about PSA screening for prostate cancer.

Digital rectal examination (DRE)

The next step is a DRE, which can be done by your GP.

During a DRE, your GP will insert a lubricated and gloved 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 should not be painful.

Prostate cancer can make the gland hard and bumpy. However, in most cases, the cancer causes no changes to the gland and a DRE may not be able to detect the cancer.

DRE is useful in ruling out prostate enlargement caused by benign prostatic hyperplasia, as this causes the gland to feel firm and smooth.

Biopsy

Your GP will assess your risk of having prostate cancer based on a number of factors, including your PSA levels, the results of your DRE, and your age, family history and ethnic group. If you are at risk, you should be referred to hospital to discuss the options of further tests.

The most commonly used test is a transrectal ultrasound-guided biopsy (TRUS). A biopsy may also be taken during a cystoscopy examination or through the skin behind the testicles (perineum).

During a TRUS biopsy, an ultrasound probe (a machine that uses sound waves to build a picture of the inside of your body) is inserted into your rectum. This allows the doctor or specialist nurse to see exactly where to pass a needle through the wall of your rectum to take small samples of tissue from your prostate.

The procedure can be uncomfortable and sometimes painful, so 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 more reliable than a PSA test, the TRUS biopsy can have problems. It can miss up to one in five cancers, because the location of the cancer is unknown when it is carried out. The doctors can see the prostate using the ultrasound scan, but not the tumour(s) if they are present.

You may need another biopsy if your symptoms persist, or your PSA level continues to rise. Your doctor may request an MRI scan of the prostate before another biopsy.

The TRUS biopsy can also find small low-risk cancers that do not need treatment, but may cause you anxiety. Many men often choose to undergo surgery or radiotherapy that may not benefit them but causes side effects, such as incontinence and erectile dysfunction.

The samples of tissue from the biopsy are studied in a laboratory. If cancerous cells are found, they can be studied further to see how quickly the cancer will spread. This process is known as "staging and grading" and helps doctors to decide which treatment is the most appropriate.

Want to know more?

• Cancer Research UK: the stages of prostate cancer
• Macmillan: grading and staging of prostate cancer

Further testing

If there is a significant chance the cancer has spread from your prostate to other parts of the body, further tests may be recommended.

These include:

• A magnetic resonance imaging (MRI) or computerised tomography (CT) scan – these scans build a detailed picture of the inside of your body.
• An isotope bone scan – this can tell if the cancer has spread to your bones. A small amount of radiation dye is injected into the vein and collects in parts of the bone where there are any abnormalities.

Want to know more?

• Cancer Research UK: prostate cancer tests