Early diagnosis of prostate cancer makes it much more likely that it will be treated successfully.

Diagnosis is likely to include a:

• PSA test;
• digital rectal exam (DRE);
• trans-rectal ultrasound scan; and
• biopsy.

A PSA test detects levels of a protein that is found in all men's prostates, but tends to be at higher levels when the prostate is unhealthy. PSA stands for prostate specific antigen and the test requires a blood test.

The PSA test is not a straightforward test for cancer: it is a test of prostate health. It is expected that men up to the age of 60 with a healthy prostate will have a result of up to 4 on a PSA test. This increases to 6.5 for men in their 70s. Results above this level indicate that there may be a problem with the prostate. This could be due to cancer, but it could also be due to benign prostatic hyperplasia (BPH) or prostatitis.

If the PSA test gives a result of over 10 it suggests that the problem is most likely to be cancer, but this is by no means definite.

Make sure that your doctor fully explains the results of the test to you.

Because things such as exercise can affect PSA levels, your doctor may want to take a second test to be able to compare the results.

There is no organised screening programme for prostate cancer, but men who would like to can have a prostate specific antigen (PSA) test. Because the test does not give a straightforward answer it can be difficult to decide whether to request one, Cancerbackup have developed a leaflet to help you make the right decision for you. Find out more on the Cancerbackup website.

A digital rectal examination can provide your doctor with valuable information about the size and shape of your prostate. The prostate is an internal gland, but it can actually be felt through your back passage. This examination involves the doctor gently inserting a lubricated and gloved finger into your rectum. This may be uncomfortable, but should not be painful.

The doctor will be able to judge whether the prostate is enlarged and whether its surface is smooth or knobbly. If you have BPH the prostate tends to remain smooth. Prostate cancer can make the prostate feel hard and uneven, although cancer can still be present if the prostate is smooth.

A trans-rectal ultrasound scan is a way of providing an image of the prostate by using sound waves. Your scan will take place at the hospital, but usually at an outpatient clinic. An ultrasound scanner, similar to the ones that produce images of babies in the womb, will be used. A small probe will be inserted into your back passage and the image of your prostate will appear on a monitor. The scan can reveal the size and density of your prostate. A biopsy or sample of cells from your prostate may be taken at the same time as the scan.

A biopsy means that a small amount of tissue is removed from the prostate to help diagnose whether there are any cancerous cells in it. The biopsy will usually be carried out at the same time as a trans-rectal ultrasound scan.

A series of needles will be used to extract tissue from your prostate. The needle will have to go through the wall of your rectum and then pierce the prostrate. This can be uncomfortable and you may feel a sharp pain. Several samples will be taken - these will then be examined in the lab to see if there are any cancerous cells. If there are, they will be graded according to how quickly they are likely to grow and spread.

If the biopsy samples do not contain any cancerous cells this does not mean that you definitely don't have cancer, as the needles may not have picked the correct spot. Your doctor will probably continue to monitor your prostate health by using the PSA test, for example.