PSA is a protein produced by prostate cancer cells. A blood test which measures the level of PSA has been developed. The prostate-specific antigen (PSA) test may help to detect early prostate cancer. However, men in the UK are not routinely offered PSA tests to screen for prostate cancer. There are many reasons for this:

• The PSA test is not completely reliable. For every 100 men with a raised PSA level only about 30 will have prostate cancer detected in a biopsy. In up to 1 in 5 men the PSA may be normal even though a cancer is present.

• The amount of PSA in the blood can be high for many reasons other than prostate cancer.

• If the PSA level is high a man will be considered for further tests, such as a biopsy, which can be painful and lead to bleeding in the urine, the semen or the bowel motions. In a few men the biopsy can lead to infection of the prostate gland, which can be difficult to get rid of. In 5-10% of men the biopsy will not show cancer even if one is present.

• Many small prostate cancers detected by PSA screening would never grow enough to cause any symptoms at all during a man’s lifetime.

• Many prostate cancers grow very slowly and the side effects from treatment (radiotherapy or surgery) may be worse than the effects of the prostate cancer. If the tests show there is an early cancer it can be difficult to decide whether or not to have treatment.

Research has not yet shown whether finding and treating prostate cancer early gives an improvement in survival. This can make it difficult to make the decision about whether to have a test. Your doctors and nurses will be aware of this difficulty and can discuss this with you.

Men who do not have symptoms but would like to have a PSA test should discuss this with their GP, who can give them all the necessary information and can then arrange the blood test if they would still like to have it.

We have a separate section with detailed information about the PSA test.