Breast Cancer in Men
- Symptoms and Types of Male Breast Abnormalities
- Risk Factors for Male Breast Cancer
- Diagnosing Male Breast Cancer
Though far less common than in women, it is possible for men to develop breast cancer. The American Cancer Society estimates that about 2,000 new cases of invasive breast cancer are diagnosed in men each year and approximately 450 men die from breast cancer annually. Male breast cancers account for approximately 1% of all breast cancer cases.
While most male breast changes are due to benign (non-cancerous) abnormalities, such as gynecomastia (non-cancerous tissue growth), men should report any persistent breast changes to their physicians for clinical evaluation. Symptoms of male breast cancer may include a breast lump, swelling, skin dimpling or puckering, nipple retraction (the nipple turns inward), redness or scaling of the nipple or breast skin, and nipple discharge.
Signs of Male Breast Cancer
Both men and women have breast tissue. Until puberty, girls and boys have a small amount of breast tissue with a few ducts under the nipple and areola (the pigmented region surrounding the nipple). When a girl reaches puberty, her ovaries produce hormones that cause breast ducts to grow, cause lobules (milk-producing glands) to form at the ends of the ducts, and increase the amount of stroma (fatty and connective tissues surrounding the ducts and lobules). When a boy reaches puberty, his testicles produce hormones that prevent further breast tissue growth.
Because men usually have much less breast tissue than women, breast lumps and other abnormalities are often easier to find on men than on women. However, because breast cancer is far less common in men and many men believe that only women get breast cancer, men often ignore the early signs of breast cancer, attributing the symptoms to infection or another cause. Some men are embarrassed to find a breast lump and delay making an appointment with their physician. Since men usually have less breast tissue than women, male breast cancer does not need to grow far to intrude into the skin and the muscles underneath the breast. Men who experience signs of breast cancer should see a physician.
The most common breast abnormality in men is a benign (non-cancerous) condition called gynecomastia. Gynecomastia is an increase in the amount of breast tissue. Gynecomastia is most common in teenage boys and is related to changes in the hormone balance during adolescence. A man with gynecomastia may have a button-like or disk-like growth under the nipple and areola (the pigmented region surrounding the nipple) that can be felt and often seen. Older men may also develop gynecomastia due to changes in their hormone balances. While gynecomastia is usually symmetrical (similar in both breasts), in some cases it may develop asymmetrically (one breast is more affected) or even unilaterally (only one breast is affected).
Less commonly, gynecomastia may be caused by tumors or diseases of certain endocrine (hormone-producing) glands that cause a man's body to produce more estrogen (a main female hormone). While some estrogen is normally produced in males, the amount is usually too small to cause breast growth. Because the liver aids in hormone metabolism, liver diseases may change a man's hormone balance and cause gynecomastia or breast cancer.
Some medications, such as certain drugs used to treat ulcers, heartburn, high blood pressure or heart failure, may also cause gynecomastia. A few studies have suggested that some cases of gynecomastia may be caused by the use of recreational drugs such as marijuana, though researchers have not conclusively linked gynecomastia to recreational drugs.
In addition, Klinefelter's syndrome, a rare genetic condition, may cause gynecomastia. Klinefelter's syndrome may also increase the risk for male breast cancer (see the section on risk factors for male breast cancer below for more information). While gynecomastia is the most common breast abnormality in men, other benign tumors that are common in women, such as fibroadenomas and papillomas, occur in men in rare occasions.
According to the National Cancer Institute, the types of breast cancer most commonly diagnosed in men are similar to those found in women. The most common type of male breast cancer is infiltrating ductal carcinoma (IDC; also called invasive ductal carcinoma). IDC is a cancer that has spread past the ducts of the breast. Ductal carcinoma in situ (DCIS; also called intraductal carcinoma) has also been seen in men. DCIS is an early stage breast cancer confined to the breast ducts. Rare cancers such as inflammatory breast cancer (a cancer in which the breast appears red and inflamed) and Paget's disease of the nipple (a cancer that begins in the breast ducts and spreads to the skin of the nipple and areola) have also been seen in men. However, lobular carcinoma in situ (LCIS; also called lobular neoplasia), a marker for increased breast cancer risk in women, has not been seen in men.