Male breast cancer is a rare cancer that forms in the breast tissue of men. Though breast cancer is most commonly thought of as a disease that affects women, breast cancer does occur in men.
Male breast cancer is most common in older men, though it can occur at any age.
Men diagnosed with male breast cancer at an early stage have a good chance for a cure. Treatment typically involves surgery to remove the breast tissue. Other treatments, such as chemotherapy and radiation therapy, may be recommended based on your particular situation.
It’s not clear what causes male breast cancer. Doctors know that male breast cancer occurs when some breast cells divide more rapidly than healthy cells do. The accumulating cells form a tumor that may spread (metastasize) to nearby tissue, to the lymph nodes or to other parts of the body.
Where breast cancer begins in men
Everyone is born with a small amount of breast tissue. Breast tissue consists of milk-producing glands (lobules), ducts that carry milk to the nipples, and fat. During puberty, women begin developing more breast tissue, and men do not. But because men are born with a small amount of breast tissue, they can develop breast cancer.
Types of breast cancer diagnosed in men include:
- Cancer that begins in the milk ducts (ductal carcinoma). Nearly all male breast cancer is ductal carcinoma.
- Cancer that begins in the milk-producing glands (lobular carcinoma). This type is rare in men because they have few lobules in their breast tissue.
- Other types of cancer. Other, rarer types of breast cancer that can occur in men include Paget’s disease of the nipple and inflammatory breast cancer.
Inherited genes that increase breast cancer risk
Some men inherit abnormal (mutated) genes from their parents that increase the risk of breast cancer. Mutations in one of several genes, especially a gene called BRCA2, put you at greater risk of developing breast and prostate cancers. If you have a strong family history of cancer, discuss this with your doctor. Your doctor may recommend that you meet with a genetic counselor in order to consider genetic testing to see if you carry genes that increase your risk of cancer.
Factors that increase the risk of male breast cancer include:
- Older age. The risk of breast cancer increases as you age. Male breast cancer is most often diagnosed in men in their 60s.
- Exposure to estrogen. If you take estrogen-related drugs, such as those used for hormone therapy for prostate cancer, your risk of breast cancer is increased.
- Family history of breast cancer. If you have a close family member with breast cancer, you have a greater chance of developing the disease.
- Klinefelter’s syndrome. This genetic syndrome occurs when boys are born with more than one copy of the X chromosome. Klinefelter’s syndrome causes abnormal development of the testicles. As a result, men with this syndrome produce lower levels of certain male hormones (androgens) and more female hormones (estrogens).
- Liver disease. Certain conditions, such as cirrhosis of the liver, can reduce male hormones and increase female hormones, increasing your risk of breast cancer.
- Obesity. Obesity is associated with higher levels of estrogen in the body, which increases the risk of male breast cancer.
- Testicle disease or surgery. Having inflamed testicles (orchitis) or surgery to remove a testicle (orchiectomy) can increase your risk of male breast cancer.
Diagnosing male breast cancer
Your doctor may conduct a number of diagnostic tests and procedures, such as:
- Clinical breast exam. The doctor uses his or her fingertips to examine your breasts and surrounding areas for lumps or other changes. Your doctor assesses how large the lumps are, how they feel, and how close they are to your skin and muscles.
- Imaging tests. Imaging tests create pictures of your breast tissue that allow doctors to identify abnormal areas. Tests may include a breast X-ray (mammogram) or an ultrasound, which uses sound waves to create images.
- Removing a sample of breast cells for testing (biopsy). A biopsy is the only definitive way to make a diagnosis of breast cancer. During a biopsy, your doctor uses a specialized needle device guided by X-ray or another imaging test to extract a core of tissue from the suspicious area.Biopsy samples are sent to a laboratory for analysis where experts determine whether the cells are cancerous. A biopsy sample is also analyzed to determine the type of cells involved in the breast cancer, the aggressiveness (grade) of the cancer, and whether the cancer cells have hormone receptors or other receptors that may influence your treatment options.
Other tests and procedures may be recommended depending on your particular situation.
Determining the extent of the cancer
Once your doctor has diagnosed your breast cancer, he or she works to establish the extent (stage) of your cancer. Your cancer’s stage helps determine your prognosis and the best treatment options. Tests and procedures used to stage breast cancer may include:
- Bone scan
- Computerized tomography (CT) scan
- Positron emission tomography (PET) scan
Breast cancer stages range from 0 to IV with 0 indicating cancer that is noninvasive or contained within the milk ducts. Stage IV breast cancer, also called metastatic breast cancer, indicates cancer that has spread to other areas of the body. Breast cancer staging also takes into account your cancer’s grade; the presence of tumor markers, such as receptors for estrogen, progesterone and HER2; and proliferation factors.
To determine your treatment options, your doctor considers your cancer’s stage, your overall health and your preferences. Male breast cancer treatment often involves surgery and may also include other treatments.
The goal of surgery is to remove the tumor and surrounding breast tissue. The procedures include:
- Removing all of the breast tissue (mastectomy). The surgeon removes all of your breast tissue, including the nipple and areola.
- Removing a few lymph nodes for testing (sentinel lymph node biopsy). The doctor identifies the lymph nodes most likely to be the first place your cancer cells would spread. Those few lymph nodes are removed and analyzed. If no cancer cells are found, there is a good chance that your breast cancer hasn’t spread beyond your breast tissue. If cancer is found, additional lymph nodes are removed for testing.
Radiation therapy uses high-energy beams, such as X-rays and protons, to kill cancer cells. In male breast cancer, radiation therapy may be used after surgery to eliminate any remaining cancer cells in the breast, chest muscles or armpit. During radiation therapy, radiation comes from a large machine that moves around your body, directing the energy beams to precise points on your chest.
Most men with male breast cancer have tumors that rely on hormones to grow (hormone-sensitive). If your cancer is hormone-sensitive, your doctor may recommend hormone therapy. Hormone therapy for male breast cancer often involves the medication tamoxifen. Other hormone therapy medications that are used in women with breast cancer haven’t been shown to be effective for men.
Chemotherapy uses medications to kill cancer cells. These medications may be administered through a vein in your arm (intravenously), in pill form or by both methods. Your doctor might recommend chemotherapy after surgery to kill any cancer cells that might have spread outside your breast. Chemotherapy may also be an option for men with advanced breast cancer.