Prostate cancer risks and causes

This page tells you about the possible causes of prostate cancer and factors that can affect your risk of developing prostate cancer. There is information below about

How common prostate cancer is

In Ireland, prostate cancer is the second most common cancer in men, after skin cancer. Every year, more than 3,890 men are diagnosed with prostate cancer in this country. This means that 1 in 6 men will be diagnosed with prostate cancer during their lifetime. The number of men getting prostate cancer in Ireland is rising- between 1995 and 2007, the number of new cases more than doubled. Although there are many men with this disease, most men do not die from it.

What risk factors are

A risk factor is anything that can increase your chance of developing cancer. Different cancers have different risk factors. Some factors can lower your risk of cancer and are known as protection factors.

 Risk factors for prostate cancer

It is not known exactly what causes prostate cancer. However, research shows that some factors may increase your risk, though scientists are still working to establish why there is a link between these factors and prostate cancer risk.

  •  Age

Age is the most significant risk factor for prostate cancer. Your risk increases as you get older. Only 1 out of every 100 (1%) of cases diagnosed in Ireland are diagnosed in men under 50. In old age, up to 8 out of 10 men (80%) have prostate cancer cells in the prostate but in some men they don’t cause any problems.

In Ireland, about 1 in 6 men will get prostate cancer at some point in their lives. However, it is important to note that this is a lifetime risk and involves men who get prostate cancer at any age, up to 85 or older. Your risk when you are younger is much lower than 1 in 6.

  •  A family history of cancer

Prostate cancer seems to run in some families. Generally speaking, if you have a father or brother diagnosed with prostate cancer you are 2.5 times more likely to get prostate cancer yourself, compared to the average man.

The age that your relative is diagnosed with prostate cancer may also be a factor. If they were diagnosed before the age of 60, this increases your risk by slightly more than if they were diagnosed after the age of 60. If you have more than one first degree relative (father or brothers) diagnosed with prostate cancer (at any age) your risk is about 4 times that of the general population.

  • Genes

Because prostate cancer seems to run in families, it suggests that in some cases there may be an inherited or genetic factor. It could be a sign that you have an inherited faulty gene in the family if

  • You have a relative who was young when they were diagnosed with prostate cancer
  • Or if your father, brother or uncle has been diagnosed with prostate cancer

The younger the age at diagnosis, the more likely it is that an inherited faulty gene is the cause. Remember that for there to be a faulty gene at work, the affected relatives have to come from the same side of your family (your mother’s side or your father’s side).

  • BRCA2

Your risk of prostate cancer is also increased if your mother has had breast cancer. This increased risk is mainly caused by an inherited faulty gene called BRCA2. Men who have a fault (mutation) in the BRCA2 gene can have a risk of prostate cancer that is 5 times higher than men in the general population. The risk can be 7 times higher in men under the age of 65.

Faults in a gene called BRCA1 may increase the risk of developing prostate cancer in men under the age of 65 by a small amount. But in men older than 65 who have a faulty BRCA1 gene there doesn’t appear to be an increased risk.

  • Lynch Syndrome

If you have lynch syndrome you may have inherited faulty genes that increase your risk of developing certain cancers. Researchers have found that men with Lynch syndrome may have a higher risk of prostate cancer than men in the general population.

It is important to remember that statistics are always a generalisation. There are likely to be specific factors at work for some men, which increase their risk.

  •  Ethnicity

Prostate cancer is more common in black Caribbean and black African men than in white or Asian men. Asian men have a lower risk than white men.

This difference seems to be due to a mixture of inherited genes and environmental factors. When men move from a country where the prostate cancer risk is low to one where it is higher their risk increases. For example, South Asian men living in Ireland have a higher risk of prostate cancer than men living in South Asia.

  •  A previous cancer

Men who have had certain cancers in the past, may have a slightly increased risk of getting prostate cancer. Studies have shown an increase in risk for men who have had kidney cancer, bladder cancer, lung cancer, thyroid cancer and melanoma skin cancer.

  •  Diet

The exact role of diet in prostate cancer is not clear, but several factors have been studied.

Men who eat a lot of red meat or high-fat dairy products appear to have a slightly higher risk of getting prostate cancer. These men also tend to eat fewer fruits and vegetables. It is not clear which of these factors is responsible for raising the risk.

Some studies have suggested that men who consume a lot of calcium (through food or supplements) may have a higher risk of developing prostate cancer. Dairy foods (which are often high in calcium) might also increase risk. However, most studies have not found a link between the levels of calcium found in the average diet, and prostate cancer, and it’s important to note that calcium is known to have other important health benefits.

  •  Hormones

Hormone levels may or may not play a part in the risk of developing prostate cancer. The prostate gland is a sex organ. It produces a liquid that is mixed with sperm to make semen. Testosterone is a sex hormone produced by the testicle and the prostate gland needs testosterone to work. It was thought in the past that having higher levels of testosterone in the blood may increase the risk of prostate cancer. But, in 2008 an analysis of 18 separate studies found no link between levels of sex hormones and prostate cancer risk.

  •  Vasectomy

A large 2014 American study showed a small increased risk of prostate cancer in men who have had a vasectomy. Vasectomy is a procedure for male sterilisation and permanent birth control. Two other large studies in 1993 also found a small increase in risk but other studies have not shown an increased risk. It seems likely that vasectomy does increase the risk of prostate cancer but the increase in risk is very small.

  •   Inflammation of the prostate

Inflammation of the prostate is called prostatitis. A meta-analysis published in 2013 combined the information from 20 studies looking at prostate cancer risk and prostatitis. It found that men with prostatitis had a higher risk of prostate cancer. But the meta-analysis included low quality research studies. The results from another higher quality study did not find a link between prostatitis and prostate cancer.  So we need more research before we know whether prostatitis increases your risk of prostate cancer.

 Protection factors for prostate cancer

We do not know the exact cause of prostate cancer, so at this time it isn’t possible to prevent most cases of the disease. Many risk factors such as age, race, and family history can’t be controlled.  However, based on what we do know, there are some things you can do that might lower your risk of prostate cancer.

  • Diet

There is some evidence that choosing a healthy diet that’s low in fat and full of fruits and vegetables may contribute to a lower risk of prostate cancer. If you want to reduce your risk of prostate cancer, consider trying to:

  • Choose a low-fat diet.
  • Increase the amount of fruits and vegetables you eat each day. Fruits and vegetables are full of vitamins and nutrients that are thought to reduce the risk of prostate cancer, though research hasn’t proved that any particular nutrient is guaranteed to reduce your risk.
  • Eat fish. Fatty fish — such as salmon, tuna and herring — contain omega-3 fatty acids, a type of fatty acid that has been linked to a reduced risk of prostate cancer.
  • Reduce the amount of dairy products you eat each day. In studies, men who ate the most dairy products — such as milk, cheese and yogurt — each day had the highest risk of prostate cancer. But study results have been mixed, and the risk associated with dairy products is thought to be small.


  • Maintain a healthy weight

Men who are obese — a body mass index (BMI) of 30 or higher — may have an increased risk of prostate cancer. If you are overweight or obese, work on losing weight. Set a reasonable goal- try to lose about half a pound a week. You can do this by reducing the number of calories you eat each day and increasing the amount of exercise you do.

  • Physical activity

Some studies show that men who are more physically active have a lower risk of getting prostate cancer. A recent review of the research evidence found that being active, especially in the work place, slightly reduced the chance of getting prostate cancer. However, more research is needed in this area.