Breast cancer in men

Men have breast tissue just like women, but their breasts are less developed. Breast cancer in men is similar to the disease in women, but there are some differences. For the most part, breast cancer in men is treated like breast cancer in women who have reached menopause (when the ovaries stop making estrogen). Less than 1% of all breast cancers occur in men.

Researchers estimate that 260 new cases of breast cancer in men will be diagnosed in Canada in 2023 and that 55 men will die from the disease.

A cancerous tumour of the breast can spread (metastasize) to other parts of the body. Cancerous tumours are also called malignant tumours.

Almost all of the breast cancers found in men are ductal carcinoma. This type of cancer starts in gland cells in the lining of a duct. Doctors will classify these tumours as non-invasive or invasive. Non-invasive means that the cancer cells have not spread beyond the duct where they started. Invasive means that the cancer cells have started to grow through the wall of the duct and into the surrounding tissue.

Most ductal carcinomas in men are invasive. After they grow through the duct, the cancer cells can continue to grow and cause a lump or thickening in the breast. The breast cancer cells can also spread to lymph nodes and other parts of the body.

Other types of breast cancer can also develop in men, but they are rare. These types of breast cancer are treated the same way in men as they are in women.

A risk factor is something that increases the risk of developing cancer. It could be a behaviour, substance or condition. Most cancers are the result of many risk factors. But sometimes breast cancer develops in men who don’t have any of the risk factors described below.

The risk of a man developing breast cancer increases with age. Most men diagnosed with the disease are over the age of 60.

There is convincing evidence that the following factors increase a man’s risk for breast cancer.

A family history of breast cancer increases the risk of breast cancer in men. The greater the number of close relatives (men or women) who have breast cancer, the greater a man’s risk for developing the disease.

BRCA gene mutations are changes to the breast cancer genes. Only a very small number of breast cancers in men are caused by an inherited gene mutation. BRCA2 mutations increase the risk of breast cancer in men more than they increase the risk in women. Mutations in the BRCA1 gene also increase the risk of breast cancer in men, but not as much as the BRCA2 gene mutation. Men who carry these gene mutations may pass them on to their children. Children of men with breast cancer have a higher risk of developing breast cancer.

Klinefelter syndrome is a very rare inherited, or genetic, disorder. Men with Klinefelter syndrome have lower than normal levels of androgens and higher than normal levels of estrogen in their bodies. These changes in hormone levels are linked with a higher risk of developing breast cancer.

Exposure to radiation, especially radiation to the chest, increases the risk of breast cancer in men.

Cirrhosis is when scar tissue replaces healthy tissue in the liver. This scarring means that the liver doesn’t make enough of the proteins that normally carry hormones into the blood. This leads to high estrogen levels and low androgen levels in the body, which are linked with a greater risk of developing breast cancer.

The following factors affect the levels of estrogen and androgen in the body, and changes in these hormones can increase a man’s risk of developing breast cancer. Further study is needed to clarify the role that these factors play in breast cancer in men.

Gynecomastia is a condition where a man’s breasts are enlarged. It is often linked with abnormal estrogen or androgen levels.

Being obese is known to increase the risk of breast cancer in women and may increase the risk of breast cancer in men. Fat cells in the body change androgens into estrogen, so men with more fat cells have higher levels of estrogen in their bodies.

Drinking alcohol affects the liver, which can affect the level of estrogen in the body. It increases the risk of breast cancer in women. It may also increase the risk in men.

Estrogen treatment for prostate cancer may increase the risk of breast cancer in men, but the risk is small compared to the benefit of the treatment. Some studies also reported that men who take estrogen as part of the process of transitioning to women may have a higher risk for breast cancer.

Certain problems with the testicles may increase the risk of breast cancer in men. These problems include an undescended testicle (called cryptorchidism) or having one or both testicles removed. Men who had mumps as an adult that caused an inflammation of the testicle may also have a higher risk for breast cancer.

It isn’t known whether or not the following factors are linked with breast cancer in men. It may be that researchers can’t show a definite link or that studies have had different results. More research is needed to see if the following are risk factors for breast cancer in men:

• occupational exposures to very hot work environments (such as working in steel mills that have blast furnaces and rolling mills)
• occupational exposure to gas and exhaust fumes
• previous breast cancer
• exposure to cancer-causing substances in the environment
• smoking
• lack of physical activity

To make the decisions that are right for you, ask your healthcare team questions about risks.

It is important for men to know what is normal for their breasts and to report any changes to their doctor. The most common sign of breast cancer in men is a painless lump, usually near or under the nipple. Other signs and symptoms include:

• discharge or bleeding from the nipple
• crusting of the nipple
• a nipple that suddenly points inward, or becomes inverted
• pain or swelling of the breast
• a lump in the armpit (called the axilla)
• an open sore, or ulcer, on the skin of the breast that doesn’t heal

Later signs and symptoms occur as the cancer grows larger or spreads to other parts of the body, including other organs. Late symptoms of breast cancer in men include:

• weight loss
• bone pain
• cough or shortness of breath
• jaundice

Diagnosing breast cancer usually begins with a visit to your family doctor. Your doctor will ask you about any symptoms you have and may do a physical exam. Based on this information, your doctor may refer you to a specialist or order tests to check for breast cancer or other health problems.

The process of diagnosis may seem long and frustrating. It’s normal to worry, but try to remember that other health conditions can cause similar symptoms as breast cancer. It’s important for the healthcare team to rule out other reasons for a health problem before making a diagnosis of breast cancer.

The following tests are commonly used to rule out or diagnose breast cancer in men. Many of the same tests used to diagnose cancer are used to find out the stage (how far the cancer has progressed). Your doctor may also order other tests to check your general health and to help plan your treatment.

Your health history is a record of your symptoms, risk factors and all the medical events and problems you have had in the past. Your doctor will ask questions about your history of:

• symptoms that suggest breast cancer
• exposure to radiation
• any occupational or environmental exposure to risk factors for breast cancer

Your doctor may also ask about a family history of breast or other types of cancer.

A physical exam allows your doctor to look for any signs of breast cancer. During a physical exam, your doctor may:

• do a clinical breast exam to check for lumps in the breast and lymph nodes, hardening or thickening of the breast tissue and changes to the skin or nipple
• feel the abdomen for organs that are larger than normal, or enlarged
• listen to the lungs

Find out more about physical exams and clinical breast exams.

Diagnostic mammography is an x-ray that uses small doses of radiation to make an image of the breast. It is used to follow up on abnormal results of a clinical breast exam. Mammography can also be used to guide the doctor to an abnormal area during a biopsy.

Find out more about mammographies.

An ultrasound uses high-frequency sound waves to make images of parts of the body. It is used to find out if a breast lump is a solid tumour or a cyst. Doctors may also use an ultrasound to guide them to an abnormal area during a biopsy.

If a man has advanced breast cancer, doctors may use an ultrasound to check if the cancer has spread to the liver (called liver metastases).

Find out more about ultrasounds.

During a biopsy, the doctor removes tissues or cells from the body so they can be tested in a lab. A report from the pathologist will confirm whether or not cancer cells are present in the sample.

A breast biopsy is the only definite way to diagnose breast cancer. Doctors may use the following types of biopsy.

Fine needle aspiration (FNA) uses a very thin needle and syringe to remove a small amount of tissue from a lump. It can help find out if the lump is a cyst or a tumour. It is the most common type of biopsy used to diagnose breast cancer in men because most lumps can be easily reached with the needle. Find out more about fine needle aspirations (FNAs).

Surgical, or open, biopsy removes all or part of a lump or abnormal area. An excisional biopsy removes the whole lump or abnormal area with a margin of healthy tissue around it. An incisional biopsy removes only part of the lump or abnormal area. It may be used if an FNA biopsy doesn’t collect enough tissue for a diagnosis. Find out more about surgical biopsies.

Breast cancer cells can break away from a tumour and travel through the lymphatic system to lymph nodes. A lymph node biopsy is used to remove lymph nodes so they can be examined under a microscope to find out if they have cancer in them. The number of lymph nodes that have cancer helps doctors determine the stage of breast cancer.

Axillary lymph node dissection (ALND) removes lymph nodes from under the arm (called the axilla). ALND is the most common way to check the lymph nodes in men.

Find out more about axillary lymph node dissections.

Men’s bodies normally make small amounts of the hormones estrogen and progesterone. Some breast cancer cells have receptors for these hormones. When the hormones attach to these receptors, they can stimulate the growth of breast cancer cells.

Hormone receptor status testing is used to find out if the breast cancer cells have estrogen receptors (ERs), progesterone receptors (PRs) or both. Most breast cancers found in men are estrogen receptor positive (ER+) and progesterone receptor positive (PR+). This information will help your healthcare team decide which treatment plan will work best for you.

Find out more about hormone receptor status testing.

ERBB2 is more commonly known as HER2 (or HER2/neu). HER2 stands for human epidermal growth factor receptor 2. It is a gene that has changed (mutated), so it helps a tumour grow (called an oncogene).

HER2 status testing is done to find out if the breast cancer cells are making more HER2 protein than normal (called overexpression). Only a small number of breast cancers in men are HER2 positive.

Find out more about HER2 status testing.

Your doctor may order other tests to check your general health. You may also have tests to find out if the cancer has spread (metastasized) to other parts of the body. These tests include:

• blood chemistry tests
• a complete blood count (CBC)
• chest x-rays
• bone scans

Find out more about a diagnosis. To make the decisions that are right for you, ask your healthcare team questions about a diagnosis.

The same grading system is used for breast cancer in men and women. Find out more about grading breast cancer.

The same staging system is used for breast cancer in men and in women. Breast cancer in men is often diagnosed at a later stage than in women. It has usually started to spread to other parts of the body when it is diagnosed.

Find out more about staging breast cancer.

If you have breast cancer, you may have questions about your prognosis. A prognosis is the doctor’s best estimate of how cancer will affect someone and how it will respond to treatment. Prognosis and survival depend on many factors. Only a doctor familiar with your medical history, the type, stage and characteristics of your cancer, the treatments chosen and the response to treatment can put all of this information together with survival statistics to arrive at a prognosis.

A prognostic factor is an aspect of the cancer or a characteristic of the person that the doctor will consider when making a prognosis. The stage of the cancer is the most important prognostic factor for breast cancer in men. Doctors will consider the number of lymph nodes that contain cancer and the size of the tumour when it was diagnosed. There is a lower risk that early stage breast cancer will come back (recur), so it has a more favourable prognosis. The risk for recurrence is greater when the cancer is at a later stage, so it has a less favourable prognosis.

Survival statistics are very general estimates and must be interpreted very carefully. Because these statistics are based on the experience of groups of people, they cannot be used to predict a particular person’s chances of survival.

There are many different ways to measure and report cancer survival statistics. Your doctor can explain the statistics for breast cancer in men and what they mean to you.

Net survival represents the probability of surviving cancer in the absence of other causes of death. It is used to give an estimate of the percentage of people who will survive their cancer. In Canada, the 5-year net survival for breast cancer in men is 80%. This means that, on average, about 80% of men diagnosed with breast cancer will survive for at least 5 years.

Survival by stage of breast cancer in men is reported as 5-year relative survival. Relative survival looks at how likely people with cancer are to survive after their diagnosis compared to people in the general population who do not have cancer but who share similar characteristics (such as age and sex).

There are no specific Canadian statistics available for the different stages of breast cancer in men. The following information comes from a variety of sources. It may include statistics from other countries that are likely to have similar outcomes as in Canada.

If you have breast cancer, your healthcare team will create a treatment plan just for you. It will be based on your health and specific information about the cancer. When deciding which treatments to offer for breast cancer, your healthcare team will consider:

• the stage
• the hormone receptor status
• the HER2 receptor status
• your personal preferences

Breast cancer in men is often treated in the same way as breast cancer in post-menopausal women. You may be offered one or more of the following treatments.

Surgery is the most common treatment for breast cancer in men. Depending on the stage of the tumour, you may have one or both of the following types of surgery.

Modified radical mastectomy is done to remove the tumour and a margin of healthy tissue around it.

Axillary lymph node dissection (ALND) is done to remove lymph nodes from under the arm (called the axilla). It is used to find out how many of these lymph nodes have cancer in them to help doctors stage the cancer.

Find out more about surgery for breast cancer.

Chemotherapy may be used to treat breast cancer in men if it has spread to lymph nodes or if there is a high risk that it will come back. The drugs used are the same as those given to post-menopausal women with breast cancer. The most common combination of chemotherapy drugs used to treat breast cancer in men is:

• CAF (or FAC) – cyclophosphamide , doxorubicin (Adriamycin) and 5-fluorouracil

There are no standard treatments for advanced, metastatic or recurrent breast cancer in men. Doctors may give the same combinations of chemotherapy drugs used to treat post-menopausal women with advanced and metastatic breast cancer. More research is needed to find out how effective these drug combinations are for men with breast cancer.

Most breast cancers in men are hormone receptor–positive tumours, which means that they may respond to hormonal therapy. It is used to lower the risk that the cancer will come back or to treat advanced or recurrent breast cancer.

Anti-estrogen drugs stop breast cancer cells from getting estrogen. Tamoxifen (Nolvadex, Tamofen) is the drug used most often for men with breast cancer. It may be offered after surgery to reduce the risk that the cancer will come back. It may also be used for advanced breast cancer.

Luteinizing hormone–releasing hormone (LHRH) agonists may be given to lower the level of sex hormones in the body. The drugs most commonly used are goserelin (Zoladex), leuprolide (Lupron, Lupron Depot, Eligard) and buserelin (Suprefact).

Anti-androgen drugs may be given to help lower the side effects from LHRH agonists and to lower the amount of androgen in the body. The anti-androgen drugs most commonly used are flutamide (Euflex) and bicalutamide (Casodex).

Aromatase inhibitors lower the amount of aromatase in the body. Aromatase is an enzyme that the body uses to make estrogen. You may be offered an aromatase inhibitor if other hormone therapy drugs don’t work. These drugs are used as standard treatments for breast cancer in post-menopausal women, but doctors are still studying their role in treating breast cancer in men.

Orchiectomy is surgery to remove the testicles. The testicles make androgen, which is changed into estrogen by tissues in a man’s body. Removing the testicles lowers the amount of androgen that can be changed into estrogen, and so lowers the amount of estrogen in the body. This is a very effective hormonal therapy, but some men may not be comfortable with this treatment option.

Find out more about hormone receptor status testing and hormonal therapy for breast cancer.

A man who has HER2-positive breast cancer may be given trastuzumab (Herceptin) in combination with chemotherapy.

Palbociclib (Ibrance) may be used to treat men with advanced breast cancer.

Find out more about targeted therapy for breast cancer.

External beam radiation therapy may be used as adjuvant therapy after surgery to treat breast cancer in men. It may be given after mastectomy if the cancer has spread to the muscles in the chest or to a large number of lymph nodes.

Find out more about radiation therapy for breast cancer.

Follow-up after treatment is an important part of cancer care. You will need to have regular follow-up visits, especially in the first 5 years after treatment has finished. These visits allow your healthcare team to monitor your progress and recovery from treatment.

A few clinical trials in Canada are open to men with breast cancer. Clinical trials look at new ways to prevent, find and treat cancer. Find out more about clinical trials.

To make the decisions that are right for you, ask your healthcare team questions about treatment. For more detailed information on specific drugs, go to sources of drug information

Recovering from breast cancer and adjusting to life after cancer treatment is different for each person, depending on the stage of the cancer, the type of treatment and many other factors. The end of cancer treatment may bring mixed emotions. Even though treatment has ended, there may be other issues you have to deal with, such as coping with long-term side effects.

Many men find it difficult to talk about their breast cancer diagnosis because it is often seen as a cancer that only women get. Your healthcare team can support you and can suggest resources if you have trouble talking about your feelings or have concerns about the following or other issues.

Lymphedema is swelling that occurs when lymph fluid can’t flow normally and builds up in the soft tissues of a limb. You may develop lymphedema in your arm when lymph nodes under your arm are removed during an axillary lymph node dissection. Find out more about lymphedema and how it can be treated.

Sexual problems, such as not being able to get or keep an erection, are a side effect of hormonal therapy for breast cancer in men. Some chemotherapy drugs used for breast cancer can cause infertility in men. Find out more about sexual problems for men and how they can be treated.