Breast cancer may occur in men. Men at any age may develop breast cancer, but it is usually detected (found) in men between 60 and 70 years of age. Male breast cancer makes up less than 1% of all cases of breast cancer.

The following types of breast cancer are found in men:

• Infiltrating ductal carcinoma: Cancer that has spread beyond the cells lining ducts in the breast. Most men with breast cancer have this type of cancer.
• Ductal carcinoma in situ: Abnormal cells that are found in the lining of a duct; also called intraductal carcinoma.
• Inflammatory breast cancer: A type of cancer in which the breast looks red and swollen and feels warm.
• Paget’s disease of the nipple: A tumor that has grown from ducts beneath the nipple onto the surface of the nipple.

Lobular carcinoma in situ (abnormal cells found in one of the lobes or sections of the breast), which sometimes occurs in women, has not been seen in men.

Radiation exposure, high levels of estrogen, and a family history of breast cancer can increase a man’s risk of developing breast cancer.

Anything that increases your risk of getting a disease is called a risk factor. Risk factors for breast cancer in men may include the following:

• Being exposed to radiation.
• Having a disease related to high levels of estrogen in the body, such as cirrhosis (liver disease) or Klinefelter's syndrome (a genetic disorder).
• Having several female relatives who have had breast cancer, especially relatives who have an alteration of the BRCA2 gene.

Male breast cancer is sometimes caused by inherited gene mutations (changes).

The genes in cells carry the hereditary information that is received from a person’s parents. Hereditary breast cancer makes up approximately 5% to 10% of all breast cancer. Some altered genes related to breast cancer are more common in certain ethnic groups. Men who have an altered gene related to breast cancer have an increased risk of developing this disease.

Men with breast cancer usually have lumps that can be felt.

Lumps and other symptoms may be caused by male breast cancer. Other conditions may cause the same symptoms. A doctor should be seen if changes in the breasts are noticed.

Tests that examine the breasts are used to detect (find) and diagnose breast cancer in men.

The following tests and procedures may be used:

• Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. The following are different types of biopsies:
  • Needle biopsy: The removal of part of a lump, suspicious tissue, or fluid, using a thin needle. This procedure is also called a fine-needle aspiration biopsy.
  • Core biopsy: The removal of part of a lump or suspicious tissue using a wide needle.
  • Excisional biopsy: The removal of an entire lump or suspicious tissue.
• Estrogen and progesterone receptor test: A test to measure the amount of estrogen and progesterone (hormones) receptors in cancer tissue. If cancer is found in the breast, tissue from the tumor is checked in the laboratory to find out whether estrogen and progesterone could affect the way cancer grows. The test results show whether hormone therapy may stop the cancer from growing.
• HER2 test: A test to measure the amount of HER2 in cancer tissue. HER2 is a growth factor protein that sends growth signals to cells. When cancer forms, the cells may make too much of the protein, causing more cancer cells to grow. If cancer is found in the breast, tissue from the tumor is checked in the laboratory to find out if there is too much HER2 in the cells. The test results show whether monoclonal antibody therapy may stop the cancer from growing.

Survival for men with breast cancer is similar to survival for women with breast cancer.

Survival for men with breast cancer is similar to that for women with breast cancer when their stage at diagnosis is the same. Breast cancer in men, however, is often diagnosed at a later stage. Cancer found at a later stage may be less likely to be cured.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis (chance of recovery) and treatment options depend on the following:

• The stage of the cancer (whether it is in the breast only or has spread to other places in the body).
• The type of breast cancer.
• Estrogen-receptor and progesterone-receptor levels in the tumor tissue.
• Whether the cancer is also found in the other breast.
• The patient’s age and general health.