Topic Overview

What is male breast cancer?

Many people believe that only women have breast cancer. Although very rare, about 1% of breast cancer occurs in adult males.^{1, 2} 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. Factors that may increase a man's risk of breast cancer include:³

• Advancing age. Although it can occur in younger men, most men diagnosed with breast cancer are older than 65.
• A history of testicular cancer or liver disease.
• A family history of breast cancer, especially if a mother, father, or sister was diagnosed with breast cancer at a young age. Having several relatives diagnosed with colon or ovarian cancer also increases a man's risk of breast cancer.
• Other hereditary factors, such as mutations in the BRCA1 and BRCA2 genes.
• Exposure to estrogen, such as might occur during treatment for prostate cancer.
• Exposure to radiation, such as during treatment for Hodgkin's lymphoma.
• Klinefelter syndrome , a genetic disorder in which an extra chromosome is present.

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.

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 surgery (mastectomy) to remove the breast. Because most men do not have very much breast tissue, breast-conserving surgery (lumpectomy) is not used. Radiation therapy is not routinely used to treat breast cancer in men.

Medicines (chemotherapy) to destroy any remaining cancer cells are used after surgery to reduce the chance that breast cancer will come back somewhere else in the body. If the breast cancer is sensitive to certain hormones (meaning that the cells have estrogen/progesterone receptors), male breast cancer is treated with a hormone-blocking agent called tamoxifen. Male breast cancer usually responds very well to chemotherapy or hormone therapy.

What to think about

Male breast cancer is rare and makes up only about 1% of all breast cancers discovered each year. 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.

Related Information

• Breast Cancer

References

Citations

1. Paley PJ (2001). Screening for the major malignancies affecting women: Current guidelines. American Journal of Obstetrics and Gynecology, 184(5): 1021–1030.
2. Gradishsar WJ (2004). Male breast cancer. In JR Harris et al., eds., Diseases of the Breast, 3rd ed., pp. 983–989. Philadelphia: Lippincott Williams and Wilkins.
3. Gradishar WJ (2004). Male breast cancer. In JR Harris et al., eds., Diseases of the Breast, 3rd ed., pp. 983–990. Philadelphia: Lippincott Williams and Wilkins.

Credits

Author	Bets Davis, MFA
Editor	Susan Van Houten, RN, BSN, MBA
Associate Editor	Pat Truman, MATC
Primary Medical Reviewer	Joy Melnikow, MD, MPH - Family Medicine
Specialist Medical Reviewer	Douglas A. Stewart, MD - Medical Oncology
Last Updated	August 18, 2009