Breast Cancer in Men (Male Breast Cancer)

Topic Overview

What is male breast cancer?

Breast cancer in men is rare. Less than 1 out of 100 cases of breast cancer occurs in a man.^{footnote 1} It develops in the small amount of breast tissue found behind a man's nipple.

What causes male breast cancer?

Although the exact cause of breast cancer is not known, most experts agree that some men have a greater risk for breast cancer than others. Male breast cancer mostly affects older men.

Things that increase a man's risk of breast cancer include:

• Radiation exposure.
• Family history of breast cancer in his female relatives.
• Inheriting gene mutations, such as the BRCA2 gene.
• Having a genetic disorder called Klinefelter syndrome or a liver disease (cirrhosis).

What are the symptoms?

The most common symptom of male breast cancer is a painless lump or swelling behind the nipple. Other symptoms can include a discharge from the nipple or a lump or thickening in the armpit. Although most men diagnosed with breast cancer are older than 65, breast cancer can appear in younger men. For this reason, any breast lump in an adult male is considered abnormal and should be checked out by a doctor.

How is male breast cancer diagnosed?

Most male breast cancer is diagnosed with a biopsy to investigate a lump or thickening in the breast or armpit. Because there is no routine screening for breast cancer and a breast lump does not usually cause pain, sometimes breast cancer isn't discovered until it has spread to another area of the body and is causing other symptoms.

How is it treated?

The main treatment for male breast cancer is modified radical mastectomy, which is surgery to remove the breast and the lymph nodes under the arm (axillary lymph nodes). In some cases, breast-conserving surgery is possible.

There hasn't been much research on breast cancer treatments in men, because male breast cancer is so uncommon. But breast cancer in men is similar to breast cancer in women, and some of the same treatments may be used. These include radiation therapy, chemotherapy, hormone therapy, and targeted therapy.

Chemotherapy may be used after surgery to reduce the chance that breast cancer will come back somewhere else in the body. Most male breast cancer has estrogen and progesterone receptors and may be treated with tamoxifen.

Additional information about male breast cancer is provided by the National Cancer Institute at www.cancer.gov/cancertopics/pdq/treatment/malebreast/Patient.

What to think about

Male breast cancer is rare and makes up less than 1% of all breast cancers discovered each year. ^{footnote 1}For this reason, many experts encourage men with breast cancer to talk to their doctors about clinical trials. These trials continue to look for better ways to treat male breast cancer.