Breast Cancer in Men: Risk Factors

Approved by the Cancer.Net Editorial Board, 09/2020

ON THIS PAGE: You will find out more about the factors that increase the chance of developing breast cancer. Use the menu to see other pages.

A risk factor is anything that increases a person’s chance of developing cancer. Although risk factors often influence the risk of developing cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. Knowing your risk factors and talking about them with your doctor may help you make more informed lifestyle and health care choices.

Most breast cancers are sporadic, meaning they develop from damage to a person’s genes that occurs by chance after they are born. There is no risk of passing this damage on to a person's children. Inherited breast cancers are less common, making up 5% to 10% of all breast cancers. They occur when gene changes called mutations or alterations are passed down within a family from generation to generation (see below). In general, a man’s average risk for breast cancer is very low. The following factors can raise a man’s risk of breast cancer:

  • Family history of breast disease or presence of a genetic mutation. About 1 out of 5 men who develop breast cancer has a family history of the disease. These men may have inherited a mutation in the BRCA1 or BRCA2 genes or other genes, such as CHEK2 and PALB2, which can increase their risk for breast cancer. Men with a BRCA2 gene mutation have a 7 in 100 chance of developing breast cancer, while men with a BRCA1 gene mutation have a 1 in 100 chance of developing breast cancer. According to ASCO recommendations, men with breast cancer should be offered genetic counseling and genetic testing for BRCA1 and BRCA2 and other inherited cancer risk genes. This testing should be offered whether or not a man has a family history of breast cancer. Learn more about BRCA gene mutations and hereditary breast cancer risk in a separate article on this website.

  • Age. The average age for men to be diagnosed with breast cancer is 65.

  • Elevated estrogen levels. Certain diseases, conditions, or treatments can increase the levels of female hormones such as estrogen, which contributes to the development of breast cancer.

    • Klinefelter’s syndrome is a rare genetic condition in which men are born with an extra X chromosome. Men with this syndrome may have an increased risk of breast cancer because they have higher levels of estrogen and lower levels of male hormones called androgens.

    • Liver disease, such as cirrhosis, can change hormone levels and cause lower levels of androgens and higher levels of estrogens.

    • Low doses of estrogen-related drugs that are given for the treatment of prostate cancer may slightly increase a person's risk of breast cancer.

  • Lifestyle factors. As with other types of cancer, research continues to show that various lifestyle factors may contribute to the development of breast cancer.

    • Being obese or even overweight increases the risk of breast cancer.

    • Lack of exercise may increase the risk of breast cancer because exercise lowers hormone levels, alters metabolism, and boosts the immune system. Increased physical activity is associated with a decreased risk of developing breast cancer.

    • Drinking 2 or more alcoholic drinks per day may raise the risk of breast cancer. However, this risk factor has not been studied in men.

The next section in this guide is Screening. It explains how tests may find cancer before signs or symptoms appear. Use the menu to choose a different section to read in this guide.