In the UK about 1 in 12 men are diagnosed with prostate cancer in their lifetime, but in the USA it is one in six men. It is thought that this may be due to the fact that in the USA more men have tests to try to detect early prostate cancer.

The number of men being diagnosed with cancer of the prostate in the UK has been increasing in recent years. It is thought that this is due to more men having tests that detect very early prostate cancers that would previously not have been found. It may also be because the number of older men in the population is increasing. Although the causes of cancer of the prostate are unknown, there are some factors that are known to increase a man's chance of developing the disease. Researchers are trying to find out more about the causes of prostate cancer.

Some ethnic groups have a higher chance of developing prostate cancer than others. For example, African-Caribbean men are more likely to develop prostate cancer. However, Asian men have a lower risk of developing it.

Men who have close relatives (a father, brother, grandfather or uncle) who have had prostate cancer are slightly more likely to develop it themselves.

It is thought that a man's risk of developing prostate cancer is significantly increased if their father or brother developed prostate cancer at or under the age of 60, or if more than one man on the same side of the family has had prostate cancer. If this is the case in your family it may indicate that a faulty gene is present, however a specific gene linked to prostate cancer has not yet been identified.

If several women in a family have had breast cancer (especially before they were 40), it could also indicate that a faulty gene may be present. This gene may increase the risk of men in the family getting prostate cancer. Only a small number of prostate cancers (5–10% or less than one in ten cases) are thought to be due to an inherited altered gene running in the family.

Our section 'Are you worried about prostate cancer?' has further information if you are worried about it running in your family.

A diet which is high in animal fat (including dairy products) and low in fresh fruit and vegetables may increase your risk of prostate cancer. A high intake of calcium (such as from dairy foods) may increase the risk of developing prostate cancer.

Tomatoes and tomato products (such as ketchup) may help to protect against prostate cancer. This may be because they contain high levels of a substance called lycopene. There is also some evidence that taking selenium supplements in the diet may help to reduce the risk of prostate cancer.