Male Breast Cancer

This factsheet discusses the main aspects of male breast cancer, including what we know about why it happens, how it is diagnosed, the treatments and some ways of coping with the disease. We hope that it helps you to discuss any questions you might have with your specialist team, and helps you take part in your treatment plan. We recommend that you read this along with Action Breast Cancer’s booklet Understanding Cancer of the Breast. Although the booklet is aimed at women, much of the information is relevant to men.

How are men's breasts diffrent to women's?

Many people are not aware that men can get breast cancer because they do think of men as having breasts. Actually both men and women have breast tissue. Until puberty, both girls and boys have similar breasts with some small ducts under the nipple. With the onset of puberty in girls, female hormones cause their breasts to grow and milk producing glands or lobes are formed at the end of the ducts. In boys, male hormones prevent breasts from growing and although there may be some increase in tissue, lobules are not properly formed as there is no requirement for milk production.

What are the causes of breast cancer in men?

Breast cancer in men is uncommon, with about 16 men diagnosed each year in Ireland. As with breast cancer in women, the causes of male breast cancer are not known. However, we do know about some risk factors, the most important being increasing age. In rare circumstances, high estrogen levels, Klinefelter's syndrome, exposure to radiation or a family history/genetic link may play a small part.

For more information download the complete "Male Breast Cancer" factsheet (pdf 812.5KB).