Risk factors of breast cancer in men
The causes of breast cancer in men aren’t fully understood, but there are some factors that may increase the risk.
However, because breast cancer in men is rare, most men who have these risk factors will never develop breast cancer.
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 extremely rare.
Family history of breast cancer
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About 1 in 5 men with breast cancer (20%) have a close relative who has also had breast cancer. 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 of breast cancers in men (10%).
There may be a breast cancer gene in a family if:
a man in the family has breast cancer
there are three close relatives on the same side of the family who developed breast cancer at any age
there are two close relatives on the same side of the family who developed breast cancer under the age of 50
there is one close relative who developed breast cancer under the age of 40
there is a close relative with breast cancer in both breasts
there is a close relative with breast cancer and another relative on the same side of the family with ovarian cancer.
(Close relatives, sometimes called your first degree relatives, are parents, children, sisters and brothers.)
Our section on cancer genetics has more information on genetic risk.
If you’re concerned that there may be a history of breast cancer in your family, you can ask your GP or breast specialist to refer you to a family cancer clinic.
Online risk assessment
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We have an interactive online tool called OPERA (Online Personal Education and Risk Assessment), which gives you personalised information about inherited breast cancer risk. OPERA is based on guidance on familial breast and ovarian cancer from the National Institute for Health and Clinical Excellence (NICE). It asks you a number of questions about your personal and family history of breast and ovarian cancer, before giving you a tailored personal assessment based on your answers.
The program also gives details of websites, helpful information and further support. OPERA isn’t intended to replace professional genetic counselling services. If you’re concerned about your genetic risk, you should still consult your GP. You may want to take along a copy of your personal assessment when you see them.
Klinefelter syndrome is a condition where men are born with one or more extra X chromosomes. Normally, men have one X chromosome and one Y chromosome (XY), while women have two X chromosomes (XX). Men with Klinefelter syndrome have one Y chromosome and two or more X chromosomes (XXY or XXXY). This can cause lower levels of testosterone.
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 1,000, but for men with Klinefelter syndrome it’s closer to 1 in 25.
Symptoms of Klinefelter syndrome may include being taller than average, having increased breast tissue (gynaecomastia), smaller testicles and infertility.
Some medical conditions
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Long-term damage to the liver such as liver cirrhosis can increase the risk of breast cancer in men. Conditions that can damage the testicles – such as having undescended testicles or having mumps as an adult – also increase the risk of breast cancer.
Being exposed to high levels of radiation may increase a man’s risk of breast cancer. Men who’ve had repeated doses of radiotherapy to their chest area at a young age may also be at increased risk.
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.
Being overweight (obese)
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Men who are overweight have a higher than average risk of getting breast cancer.
There is some evidence that heavy drinking over a sustained period of time increases a man’s risk of developing breast cancer.