The exact causes of breast cancer in men are not fully understood, but certain factors may increase the risk. These are called ‘risk factors’, and include:
The most important risk factor is increasing age. Most men who get breast cancer are over 60, although younger men can be affected.
A small number of men have an increased risk of developing breast cancer because they have a significant family history.
If you have a significant family history, it may be because an inherited altered gene that increases the risk of breast cancer runs in your family. The most common altered genes that increase the risk of breast cancer are called BRCA1 and BRCA2 (BRCA stands for BReast CAncer). BRCA2 is more commonly associated with breast cancer in men.
If you have inherited an altered gene, your risk of developing breast cancer (and possibly other cancers) increases, but the increased risk of breast cancer is still less than women in the general population. If you have children, or are planning to have children, each of them will also have a 50% chance of inheriting the altered gene.
If you’re concerned about your family history, the first step is to talk to your GP.
Men who have had previous radiotherapy to the chest, for example to treat Hodgkin’s lymphoma (Hodgkin’s disease), may have a slightly increased risk of developing breast cancer.
This increased risk is related to the long-term effects of radiation on normal healthy tissue, not because anything has gone wrong with the treatment.
Some breast cancers are stimulated to grow by hormones. Oestrogen is the main hormone linked to breast cancer development. All men have a small amount of oestrogen.
There is some evidence that men are at greater risk of developing breast cancer if they have higher than normal levels of oestrogen. High oestrogen levels can occur in men because of:
- long-term liver damage, particularly cirrhosis
- obesity (being very overweight)
- some genetic conditions, for example Klinefelter’s syndrome.