Risk factors for breast cancer in men

The causes of breast cancer in men aren’t fully understood, but some factors can slightly increase the risk of developing it. Breast cancer in men is rare, so most men who have these risk factors will never develop it.

Your risk increases if:

  • you are older – it is most common in men over 60 years old
  • you have a family history of breast cancer – breast cancer is sometimes linked to an inherited breast cancer gene, and if you have a history of it you should speak to your GP
  • you have Klinefelter syndrome – born with one or more extra X chromosomes.

Other conditions, such as high oestrogen levels or damage to the testicles, can also increase the risk.

Your risk may be increased if you’ve been exposed to high levels of radiation or worked in hot environments such as blast furnaces or steel works.

Risk factors and causes

The exact cause of breast cancer is unknown. But certain things, called risk factors, can increase a man’s chances of developing it. However, because breast cancer in men is rare, most men who have these risk factors will never develop breast cancer.


Age

The risk of breast cancer in men increases with age. It’s most common in men over 60 years old. Breast cancer in young men is rare.


Family history of breast cancer

Men who have close relatives with breast cancer may have an increased risk of developing breast cancer. Close relatives, sometimes called your first degree relatives, are parents, children, sisters and brothers. About 1 in 5 men (20%) with breast cancer have a close relative who has also had breast cancer.

The increased risk may be due to inherited faulty genes. Our genes store the biological information we inherit from our parents. The genes most commonly linked to an increased risk of breast cancer in families are BRCA1 and BRCA2. Men in families with the BRCA2 gene are more likely to develop breast cancer than men in BRCA1 families. It’s thought that the BRCA2 gene may cause up to 1 in 10 (10%) of breast cancers in men.

If you’re concerned about breast cancer in your family, you can ask your GP or breast specialist to refer you to a family history clinic or a genetics clinic.

I was diagnosed with breast cancer three years ago. I wasn’t surprised – my mother died from it and my sister was diagnosed too. There seems to be a genetic link.

Stephen


Klinefelter syndrome

This is a rare syndrome which affects only men. Normally, males are born with one X chromosome and one Y chromosome (XY), while females have two X chromosomes (XX). Men with Klinefelter syndrome have one Y chromosome and two or more X chromosomes (XXY or XXXY).

Symptoms of Klinefelter syndrome may include being taller than average, having increased breast tissue (gynaecomastia), lower levels of testosterone, smaller testicles and infertility.

Men with Klinefelter syndrome have a higher risk of breast cancer. For most men, the lifetime risk of developing breast cancer is about 1 in 1000, but for men with Klinefelter syndrome it’s closer to 1 in 25.


Radiation

Being exposed to radiation may increase a man’s risk of breast cancer. Men who have had repeated doses of radiotherapy to their chest area at a young age may also be at increased risk.


High oestrogen levels

Men may be at risk of developing breast cancer if they have higher levels of oestrogen than normal. This can be caused by long-term damage to the liver, such as liver cirrhosis. This can be caused by heavy drinking over a long period of time. Oestrogen levels can also be affected by being very overweight. Increased levels of oestrogen can affect the growth of breast cancer cells.


Testicular effects

Conditions that can affect or damage the testicles may also increase the risk of breast cancer. These include:

  • having undescended testicles
  • having surgery to remove one or both testicles
  • having mumps as an adult.


Some occupations

Men who work in hot environments, such as blast furnaces, steel works and rolling mills, may have a slightly increased risk. This is probably related to heat damage to the testicles. Some studies have also linked long-term exposure to petrol and exhaust fumes with breast cancer in men.