ON THIS PAGE: You will find out more about the factors that increase the chance of developing this type of cancer. To see other pages, use the menu on the side of your screen.
A risk factor is anything that increases a person’s chance of developing cancer. Although risk factors often influence cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and talking about them with your doctor can help you make more informed lifestyle and health care choices.
A man’s average risk for breast cancer is low; out of 1,000 men with an average risk of the disease, one will develop breast cancer. Generally, most breast cancers are sporadic, meaning they develop from damage to a person’s genes that occur by chance after they are born and there is no risk of passing on the gene to a person's children. Inherited breast cancers are less common and occur when gene changes, called mutations, are passed within a family from one generation to the next (see below). The following factors can raise a man’s risk of breast cancer:
Family history of breast disease or presence of a genetic mutation. About one out of five men who develop breast cancer has a family history of the disease. Men with breast cancer gene (BRCA) gene mutations may be at increased risk for breast cancer and prostate cancer. Men with BRCA2 gene mutations have a 6 in 100 chance of developing breast cancer, whereas men with BRCA1 gene mutations have a 1 in 100 chance of developing 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, a rare genetic condition in which men are born with an extra X chromosome, may increase the risk of breast cancer because men with Klinefelter’s syndrome have higher levels of estrogen and lower levels of male hormones called androgens.
- Liver disease, such as cirrhosis, can change hormone levels and cause low 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 the risk of breast cancer.
Radiation. High doses of radiation may increase the risk of breast cancer. An increased risk of breast cancer has been seen in long-term survivors of atomic bombs, people with lymphoma who received radiation therapy to the chest, people who have had many x-rays for conditions such as tuberculosis, residual thymic disease, or acne, non-cancerous conditions of the spine, and in children who received radiation therapy for ringworm.
Lifestyle factors. As with other types of cancer, studies continue 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 two or more alcoholic drinks per day may raise the risk of breast cancer. However, this risk factor has not been studied in men.
Research continues to look into what factors cause this type of cancer and what people can do to lower their personal risk. There is no proven way to completely prevent this disease, but there may be steps you can take to lower your cancer risk. Learn more about weight management, physical activity, and alcohol consumption in the Prevention and Healthy Living section of this website . Talk with your doctor if you have concerns about your personal risk of developing this type of cancer.
Regular self-examinations, clinical breast examinations performed by a doctor or other health care professional, and mammography are important ways to find breast cancer early, when it is easier to treat. Men should be familiar with the feel of their breast tissue, so they can talk with their doctor if they notice any lump or change. During an annual physical examination, your doctor will perform a clinical examination of the breast. Mammograms are not routinely offered to men and may be difficult to perform because of the small amount of breast tissue. A doctor may recommend regular mammography for men with a strong family history of breast cancer or for those with a genetic mutation that increases the risk of developing the disease.
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