Male Breast Cancer

Breast cancer is cancer that forms in the cells of the breast. It is the most common cancer diagnosed in women in the United States, but it can also occur in men. Breast cancer is about 100 times less common among men than among women. For men, the lifetime risk of getting breast cancer is about 1 in 1,000. Male breast cancer accounts for less than 1% of all breast cancers in the United States.

Like for women, the risk of breast cancer in men is influenced by age, family history, inherited gene mutations, hormone levels, and environmental exposure to certain cancer-causing chemicals.

There are many similarities between breast cancer in men and women, but there are some important differences that affect finding it early. The most obvious difference between the male and female breast is size. Because men have very little breast tissue, it is easier for men and health care professionals to feel small masses (tumors). On the other hand, because men have so little breast tissue, cancers do not need to grow very far to reach the nipple, the skin covering the breast, or the muscles underneath the breast. Therefore, even though breast cancers in men tend to be slightly smaller than in women when they are first found, they have often already spread to nearby tissues or lymph nodes. The extent of spread is one of the most important factors in the prognosis (outlook) of a breast cancer.

Another difference is the awareness and amount of attention given to breast cancer in women and men. Women tend to be aware of this disease and its possible warning signs, but many men often do not think that they can get it at all. Some men ignore breast lumps or think they are caused by an infection or some other reason, or some men are embarrassed when they find a breast lump. For these reasons, a man may not get medical treatment until the mass has had a chance to grow. This could delay diagnosis and reduce a man's chances for successful treatment. Because breast cancer is so uncommon in men, there is unlikely to be any benefit in screening men in the general population for breast cancer with mammograms or other tests.

Surgery, radiation therapy, chemotherapy, and hormone therapy are often used to treat breast cancer in men.

The cause of breast cancer is not entirely clear. Cancer occurs when some breast cells begin growing abnormally. These cells divide more rapidly than healthy cells do and continue to accumulate, forming a lump or mass. The cells may spread (metastasize) through your breast to your lymph nodes or to other parts of your body.

Hormonal, lifestyle, and environmental factors may increase the risk of getting breast cancer, but it is not clear why some people who have no risk factors develop cancer and other people with risk factors never do. Breast cancer is likely caused by a complex interaction of genetic makeup and environment. A small proportion of breast cancers are linked to gene mutations passed through generations of a family, but there are several inherited mutated genes that can increase the likelihood of breast cancer. The most common are breast cancer gene 1 (BRCA1) and breast cancer gene 2 (BRCA2), both of which significantly increase the risk of both breast and ovarian cancer in women. In men, only BRCA2 seems to be associated with an increased risk of breast cancer.

Other factors that are associated with an increased risk of male breast cancer include:

• increasing age. The risk of breast cancer increases as men age. The average age of diagnosis of male breast cancer is 68 years old.
• a family history of breast cancer. Approximately 1 in 5 men with breast cancer have a close male or female relative with the disease.
• radiation exposure. If you received radiation treatments to your chest as a child or young adult, your risk of breast cancer is increased.
• obesity. Being obese increases the risk of breast cancer.
• drinking alcohol. Drinking alcohol increases the risk of breast cancer.
• estrogen treatment. Men who received estrogen-related therapy for prostate cancer may have a slightly increased risk of breast cancer.
• liver disease. Men with liver disease have altered levels of sex hormones, which may contribute to benign breast conditions and breast cancer.
• testicular conditions. Infections or conditions that affect the testicles may increase the risk for male breast cancer.

See your doctor about a lump or swelling in the breast, skin dimpling, nipple changes, or discharge. Breast cancer in men is uncommon, so any new breast change should be checked promptly.