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Breast cancer in men

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Breast cancer occurs mainly in women, but men can get it, too. Many people do not realize that men have breast tissue and that they can develop breast cancer. Cells in nearly any part of the body can become cancerous and can spread to other areas.


Breast cancer starts when cells in the breast begin to grow out of control. These cells usually form a tumor that can often be seen on an x-ray or felt as a lump. The tumor is malignant (cancer) if the cells can grow into (invade) surrounding tissues or spread (metastasize) to distant areas of the body.

In the Americas, less than 2% of all breast cancers occur in men.

Men and women both have breasts that are made up of fatty tissue, fibrous tissue called stroma, nipples, ducts (tubes that carry milk to the nipples), and lobules (milk-producing glands). During puberty, the hormones in girls’ bodies cause their breast tissue to grow. The hormones in boys’ bodies restrict the growth of their breasts, so their breast tissue stays smaller. Most breast cancers in men are ductal carcinomas, which begin in the milk ducts.

In 2022, about 2,710 American men are expected to be diagnosed with breast cancer, and about 530 are expected to die from the disease. An average man’s risk of being diagnosed with breast cancer in his lifetime is about 1 in 1,000,


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.


Male breast tissue

Until puberty (on average around age 9 or 10), young boys and girls have a small amount of breast tissue consisting of a few ducts located under the nipple and areola (area around the nipple). At puberty, a girl's ovaries make female hormones, causing breast ducts to grow and lobules to form at the ends of the ducts. Even after puberty, boys and men normally have low levels of female hormones, and breast tissue doesn’t grow much.   Men's breast tissue has ducts, but only a few if any lobules.

Breast cancer can spread when the cancer cells get into the blood or lymph system and are carried to other parts of the body.  

The lymph system is a network of lymph (or lymphatic) vessels found throughout the body. The lymph vessels carry lymph fluid and connect lymph nodes. Lymph nodes are small, bean-shaped collections of immune system cells. Lymph vessels are like small veins, except that they carry a clear fluid called lymph (instead of blood) away from the breast.

Lymph contains tissue fluid and waste products, as well as immune system cells. Breast cancer cells can enter lymph vessels and start to grow in lymph nodes. Most of the lymph vessels of the breast drain into:


  * Lymph nodes under the arm (axillary nodes)

  * Lymph nodes around the collar bone (supraclavicular [above the collar bone] and infraclavicular [below the collar bone] lymph nodes)

  * Lymph nodes inside the chest near the breast bone (internal mammary     lymph nodes)


Since there are relatively few cases of breast cancer in men compared to women, there is less information and research focused specifically on male breast cancer. As a result, treatment decisions for male breast cancer are often based on studies of breast cancer in women.

Unfortunately, men are often diagnosed with breast cancer at a more advanced stage. The main reason is they don’t have routine screening mammograms like women do to find breast cancer at an early stage when it is easier to treat. And since men may not know they can get breast cancer, they’re usually not on the lookout for changes in their breast tissue, and may not realize they should talk to their doctor about a lump, pain, swelling, or other symptoms.


Risk factors for male breast cancer

The risk of male breast cancer increases as you age. The average age of men diagnosed with breast cancer in North America is about 67. But breast cancer can occur in young men, too.

Family history of breast cancer

A man’s risk for breast cancer is higher if any of his close relatives have had breast cancer, and especially if any male relatives have had the disease.

Genetic mutations

Men who inherit certain genetic mutations from their mothers or fathers have a higher risk of developing breast cancer. A man who inherits a /BRCA1/ mutation has about a 1% risk of developing breast cancer in his lifetime, compared to a risk of 0.1% (about one in 1,000) for the average man. A man who inherits a /BRCA2/ mutation has a 7% to 8% risk.

Mutations in the /ATM/, /CHEK2/, /PALB2/, and other genes are also linked to breast cancer in men, but more research is needed to understand those risks.

High estrogen levels

You may think of testosterone as a male hormone and estrogen as a female hormone. The truth is, both men and women have different levels of testosterone and estrogen in their bodies. Men have less estrogen than women, but all men have some estrogen in their bodies. Higher levels of estrogen can increase the risk of male breast cancer. Men (and people assigned male at birth) can have high estrogen levels as a result of:  

    hormone therapy for prostate cancer (androgen suppression therapy) hormone therapy taken by transgender women (as part of male-to-female transition; also called feminizing hormone therapy or gender-affirming hormone replacement therapy)

* *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.

**having an undescended testicle

**Radiation exposure* If a man has received radiation therapy to the chest, such as for the treatment of Hodgkin lymphoma, he has an increased risk of developing breast cancer.


Types of breast cancer diagnosed in men include:

  Most breast cancers are *carcinomas*. In fact, breast cancers are often a type of carcinoma called *adenocarcinoma*, which starts in cells that make glands (glandular tissue). Breast adenocarcinomas start in the ducts (the milk ducts) or the lobules (milk-producing glands).

There are other, less common, types of breast cancers, too, such as *sarcomas*, phyllodes, Paget’s disease and angiosarcomas which start in the cells of the muscle, fat, or connective tissue.

Special types of invasive breast carcinoma


There are some special types of breast cancer that are sub-types of invasive carcinoma. They are much less common than the breast cancers named above.

Some of these may have a better or worse prognosis than standard infiltrating ductal carcinoma.

  * Adenoid cystic (or adenocystic) carcinoma

  * Low-grade adenosquamous carcinoma (this is a type of metaplastic carcinoma)

  * Medullary carcinoma

  * Mucinous (or colloid) carcinoma

  * Papillary carcinoma

  * Tubular carcinoma

  * Metaplastic carcinoma (including spindle cell and squamous, except low grade adenosquamous carcinoma)

  * Micropapillary carcinoma

  * Mixed carcinoma (has features of both invasive ductal and lobular)


In general, these subtypes are still treated like standard infiltrating carcinoma.



Signs and symptoms of male breast cancer can include:

  * A painless lump or thickening in your breast tissue

  * Changes to the skin covering your breasts, such as dimpling, puckering, redness or scaling

  * Changes to your nipple, such as redness or scaling, or a nipple that begins to turn inward

  * Discharge from your nipple

  *A lump in the armpit

  *Sores or a rash on the nipple and areola (the dark area around the nipple)

  *Change in the size or shape of the breast


Diagnosis of male breast cancer

Doctors use a number of different diagnostic tests to find out whether 0or not breast cancer is present and, if so, whether it has spread outside the breast. Diagnostic tests are also used to gather more information about the cancer to guide decisions about treatment.

If you have possible symptoms of male breast cancer, your doctor may recommend some combination of the following diagnostic tests:

    breast physical exam




If you are diagnosed with breast cancer, your doctor may recommend additional tests, including:

    breast MRI

    blood marker tests

    chest X-ray

    bone scan

    computerized tomography (CT) scan

    positron emission tomography (PET) scan


Treatment of male breast cancer


Depending on the details of your diagnosis, treatment options for male breast cancer can include:



 radiation therapy

 targeted therapy

 hormonal therapy



If you are a man who has been diagnosed with breast cancer, you and your medical team will develop a treatment plan based on the characteristics of cancer and other factors. Men who haven’t been diagnosed with breast cancer but who have a family history of breast, ovarian, pancreatic, or prostate cancer, or who have a family member who was found to have an inherited gene mutation that increases the risk of cancer, should also consider getting genetic testing.

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