Find out about the possible causes of breast cancer in men and how you can reduce your risk.

Breast cancer in men is rare, with only around 1 in 870 men receiving a breast cancer diagnosis in their lifetime. However, there are some things that can increase your risk of developing the disease.

Breast cancer in men is thought to be caused by a combination of factors. We are still learning more about what can increase and decrease a man’s risk of developing the disease.

Having particular factors that increase breast cancer risk doesn’t mean that you will definitely develop this rare disease. Equally, not having many factors that increase breast cancer risk doesn’t mean that you won’t develop the disease.

Even if you have a risk factor and are diagnosed with breast cancer, there’s no way of proving that the risk factor actually caused it.

Risk factors for breast cancer in men:

  • Increasing age
  • Genetics – breast cancer in the family
  • Exposure to ionising radiation
  • Hormone imbalances

Age

Your risk of breast cancer steadily increases as you get older. Most men who develop breast cancer are over 60.

Genetics – breast cancer in the family

Faults in certain genes – such as BRCA2 and BRCA1 – are known to increase the risk of men and women developing breast cancer. Of every 100 men with a fault in BRCA2, about six to nine will develop breast cancer in their lifetime. The risk with BRCA1 is smaller, with about one in every 100 men who carry the genetic fault developing breast cancer.

Between one and two out of every 10 men with breast cancer have inherited faults in these genes. If you have a strong family history of breast cancer, it is possible you might carry these faulty genes and be able to pass them on to your children.

It’s not easy to give a single definition of a family history of breast cancer, because there are many different patterns. However, you might have an increased risk of developing the disease if you have an unusually high number of close relatives (mother, sisters or daughters) on one side of the family with breast cancer and/or relatives who developed breast cancer at a young age. Other factors that contribute to a family history are cases of ovarian cancer, cancer in both breasts, male relatives with breast cancer, or having a certain geographical or ethnic background, such as an Ashkenazi Jewish ancestry.

If you are concerned about your risk of breast cancer and family history, you should visit your GP (or breast care team) to discuss this. For more information, see our family history guide.

Men with the genetic condition Klinefelter’s Syndrome also have an increased risk of breast cancer, although the overall risk is still low. Men with this rare condition are born with an extra X chromosome, which decreases the levels of androgens (male hormones) in their body.

More information on Klinefelter's Syndrome is available from the Klinefelter's Syndrome Association

Exposure to ionising radiation

Radiotherapy treatment to the chest – for example to treat Hodgkin’s lymphoma – is known to increase breast cancer risk in women. There is some evidence that it may slightly increase risk in men too. If you have any concerns about previous chest radiotherapy, contact your specialist or doctor.

Hormonal factors

Men normally produce high levels of androgens – male hormones – such as testosterone, and low levels of the female hormone, oestrogen. Hormone imbalances where oestrogen levels are raised and androgen levels are decreased may slightly increase a man’s risk of developing breast cancer. This is because oestrogen can promote the growth of some breast cancers.

Here are some of the things that can cause hormone imbalances:

  • Klinefelter’s Syndrome
  • Liver cirrhosis, which is scarring of the liver due to long-term damage
  • Obesity – fatty tissue can convert male hormones into oestrogen. With a greater number of fat cells in their bodies, obese men produce more oestrogen

Reducing your risk

For women, we know that several lifestyle factors can play a big part in reducing the risk of breast cancer developing. For example, maintaining a healthy weight, being regularly physically active and limiting the amount of alcohol you drink.

However, in men, it’s more complicated and it’s not yet clear what effects some of these factors have on the development of breast cancer in men. Part of the problem is that breast cancer in men is much rarer than breast cancer in women, and this makes it much more difficult to research.

Research is still ongoing and studies such as the Male Breast Cancer study, the Male Breast Cancer Pooling Project, and the International Male Breast Cancer Program are working to better our understanding of breast cancer in men, and the factors which may influence a man’s risk.

Even though we don’t yet fully understand how effective lifestyle changes are in reducing the risk of breast cancer in men, we still recommend leading a healthy lifestyle. Maintaining a healthy weight, being regularly physically active and limiting the amount of alcohol you drink are all good for your general health. For more information on maintaining a healthy weight, including tools to assess your weight and advice on losing weight, you can visit the NHS Choices website

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Information last reviewed: June 2016

Next review due: June 2019

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