Breast Cancer in Men
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.
- Symptoms and Types of Male Breast Abnormalities
- Risk Factors for Male Breast Cancer
- Diagnosing Male Breast Cancer
- Treating Male Breast Cancer
- Survival Rates for Male Breast Cancer
- Additional Resources and References
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.
While only approximately 1% of all breast cancer cases occur in men, several risk factors have been identified that make some men more likely to develop breast cancer than others. These risk factors include:
Advancing age: The average age of men diagnosed with breast cancer is between 60 and 70 years old.
Family history: Approximately 20% of men with breast cancer have close female relatives who have (or have had) breast cancer.
Radiation exposure: Prior exposure to radiation (usually for treatment of a cancer inside the chest such as Hodgkin's or non-Hodgkin's lymphoma) is a risk factor for male breast cancer.
Liver disease: The liver helps with hormone metabolism by binding proteins that carry hormones in the blood. Men with severe liver diseases such as cirrhosis tend to have lower levels of androgens (male hormones) and higher estrogen levels (female hormones), which puts them at an increased risk of developing gynecomastia (non-cancerous tissue growth) and breast cancer. According to the American Cancer Society, in certain Middle Eastern and African countries, severe liver disease due to infection with certain parasites is common. Men in these countries may have a significantly higher risk of breast cancer than men in the United States.
Treatment with estrogen: Estrogen may feed some types of cancerous breast tumors, and therefore, men who have been treated with estrogen may be at an increased risk for breast cancer. However, according to the American Cancer Society, the risk of breast cancer due to estrogen treatment appears to be small. The benefit of slowing the growth of prostate cancer with estrogen, for example, often outweighs the risk of developing breast cancer. Also, men who take high doses of estrogen as part of a gender-changing procedure may be at a higher risk for breast cancer.
BRCA2 gene mutations: When functioning normally, the breast cancer gene 2 (BRCA2) helps repair damage to DNA (a process that also prevents tumor development). However, some men and women have genetic mutations of the BRCA2 gene, which can lead to an increased risk of breast cancer. BRCA1 (breast cancer gene 1) mutations also increase the risk for breast cancer in women. Men who carry mutations of the BRCA1 gene may pass the gene along to their daughters, who would be at an increased risk of developing breast cancer.
Klinefelter's syndrome: Normally, men are born with one X chromosome and one Y chromosome (the chromosomes which determine gender). Klinefelter's syndrome is a genetic condition that occurs when a man is born with two or more X (female) chromosomes. Approximately 1 in 850 men have Klinefelter's syndrome. Symptoms of Klinefelter's syndrome include longer legs, a higher voice, a thinner beard than average men, smaller than normal testicles, and the inability to produce sperm (infertility). Men with Klinefelter's syndrome also have lower levels of androgens (male hormones) and higher levels of estrogen (female hormones). Therefore, men with Klinefelter's syndrome are at a higher risk of developing gynecomastia (non-cancerous tissue growth) and breast cancer.
A breast lump or abnormality will usually first be investigated with a physician-performed clinical breast exam and complete physical (to check for enlarged lymph nodes, liver problems, etc.). The physician will also assess the patient's personal and family history, since male breast cancer tends to occur more frequently when one or more female relatives also has (or has had) breast cancer. Because men have significantly less breast tissue than most women, a breast lump or other abnormality is usually much easier to detect with physical examination on a man than on a woman. However, male breast cancer tends to affect the skin and muscles underneath the breast more quickly than female breast cancer. While male breast cancer tends to be smaller when found, it is more likely to have spread past the breast than female breast cancer.
If a physician is concerned about his or her findings during a clinical breast exam, he or she may order a mammogram to further investigate the breast abnormality. Diagnostic mammography involves taking x-ray images of the breast. In some cases, special mammography views such as spot compression or magnification are needed. Additional tests such as ultrasound or a nipple discharge examination may also be ordered. If testing reveals the possibility of cancer, a breast biopsy may be performed (although the mammographic signs of some benign conditions such as gynecomastia can be quite characteristic and biopsy may not be needed in some cases). A biopsy involves taking samples of breast tissue for pathological examination under a microscope. A biopsy is the only definitive way to determine whether breast cancer is present. Click here to learn about the different methods of breast biopsy.
Surgery: usually a modified radical mastectomy is performed to remove the breast, the lining over the chest muscles, and part of the chest wall muscles. Some or all of the axillary (underarm) lymph nodes may also be removed and sent to the laboratory for pathological examination to determine whether breast cancer has spread past the breast.
Radiation therapy: involves using high-energy rays to stop cancer cells from growing and dividing.
Chemotherapy: treatment with anticancer drugs.
Hormone therapy: often used if the breast cancer cells have estrogen receptors or progesterone receptors. Over 80% of male breast cancers have estrogen receptors. Hormone therapies used to treat male breast cancer include drugs tamoxifen (brand name Nolvadex) and megace (brand name, Megestrol). Tamoxifen is an antiestrogen and works by blocking estrogen in the breast, thereby slowing the growth and reproduction of breast cancer cells that depend on estrogen for survival. Megace is an anti-androgen and blocks the effect of androgen (a male hormone) on breast cancer cells. Researchers are not certain why blocking androgen in the breast helps treat male breast cancer.
In the past, it was believed that the prognosis (expected outcome) for male breast cancer was worse than for female breast cancer. Today, it is widely accepted that the survival rates are similar when treatment of the tumor begins at the same stage. However, male breast cancer tends to be diagnosed in later stages than female breast cancer.
The five-year survival rates for male breast cancer are based on the stage of the breast cancer. Staging is the process physicians use to assess the size and location of a patient's cancer. Identifying the cancer stage is one of the most important factors in selecting treatment options. Breast cancer stages range from Stage 0 (the earliest stage) to Stage IV (advanced breast cancer). The stage of the breast cancer is determined by the tumor size, lymph node involvement, and the extent to which the cancer has spread (metastasis). Click here to learn more about the stages of breast cancer.
The following chart is an approximate survival rate for each stage of breast cancer. The percentages are only averages. The chances of survival will differ for each man depending on his own medical situation and several other factors, including new treatment options, how he responds to treatment, etc.
|Stage of Male Breast Cancer||5-year Relative |
Source: American Cancer Society
- The American Cancer Society provides information on male breast cancer at http://www.cancer.org/
- The National Cancer Institute provides information on male breast cancer at http://www.cancer.gov/
- The University of Pennsylvania's Oncolink document, "NCI/PDQ Physician Statement: Male Breast Cancer," is available at http://cancer.med.upenn.edu/
Updated: January 29, 2008