It’s not clear exactly what causes breast cancer in men, although several things that can increase your risk of developing the condition have been identified.

About cancer

The body is made up of millions of different cells. Cancer happens when cells multiply in an abnormal way. When cancer affects organs and solid tissues, it causes a growth called a tumour to form. Cancer can occur in any part of the body where cells multiply abnormally.

In breast cancer, cells in the breast tissue are affected.

Left untreated, cancer can quickly grow and spread from the breast into nearby tissue or other parts of the body. This usually happens through the lymphatic system, but can also spread through the bloodstream.

The lymphatic system is a series of glands located throughout the body and linked together in a similar way to the blood circulation system.

Once the cancer reaches your lymphatic system, it can spread to any other part of your body, including your bones, blood and organs.

Increased risk

A number of things that can increase your risk of breast cancer developing have been identified.

Age

Like many cancers, men have an increased risk of developing breast cancer as they get older. Most cases are diagnosed in men aged 60-70. It’s  rare for young men to develop the condition.

Genetics and family history

A genetic mutation is where instructions carried in all living cells become scrambled in some way which means one or more of the body’s processes do not work in the way they should.

There are a number of genetic mutations known to increase your risk of developing breast cancer. The most significant mutation identified is known as the BRAC2 mutation. One study carried out in the UK found one in 20 men with breast cancer have the BRAC2 mutation.

There is also evidence that breast cancer can run in families, as one in five men who develop breast cancer have a first-degree relative, such as a mother or sister, who has developed breast cancer.

Routine testing for the faulty genes that cause breast cancer in men is not usually carried out on the NHS. However, some private clinics offer gene testing. Tests can be expensive with prices ranging from around £2,000 to £3,000.

Oestrogen

There is evidence that high levels of the hormone oestrogen, or prolonged exposure to it, can increase the risks of breast cancer in men.

Compared to women, men tend to have low levels of oestrogen, but there are circumstances that can increase the levels of oestrogen in men. These include:

• hormone treatments – man-made (synthetic) versions of oestrogen are often used to treat prostate cancer and are also given to transsexuals undergoing a male to female sex change
• obesity – obese men have higher levels of oestrogen than normal
• cirrhosis – long-term scarring of the liver often caused by long-term alcohol misuse

There is also a rare genetic condition affecting males called Klinefelter’s syndrome. This is a congenital condition (boys are born with it) and it means affected males produce less of the hormone testosterone than usual.

As testosterone usually helps to limit the effect of oestrogen, men with Klinefelter’s syndrome are more likely to develop breast cancer than the general male population.

Occupational risks

There is evidence that men who work in hot environments are twice as likely to develop breast cancer compared with men who work in cooler environments. Environments linked to an increased risk of breast cancer in men include:

• blast furnaces
• steel works
• rolling mills – a factory where metal (usually steel) is shaped using rollers
• car manufacturing plants

One hypothesis to help explain the link between working environment and the increased risk of developing breast cancer is that excessive heat may damage the testicles, which could lead to an increase in oestrogen levels.

Another hypothesis is that working in hot environments usually involves exposure to certain chemicals which may increase the risk of developing breast cancer in men.

Rates of breast cancer are also unusually high in men who manufacture perfumes and soaps. They are seven times more likely to develop breast cancer than the male population at large. The reason for this increased risk is still unclear. Exposure to certain chemicals seems to be an obvious possibility, but this has not yet been proven.

Radiation

Exposure to radiation has been linked to an increased risk of developing breast cancer in men.

Research has found that men who received a course of radiotherapy (where high energy X-rays are used to kill cancerous cells) directed at the upper chest were seven times more likely to develop male breast cancer compared to the population at large.

However, even a seven-fold increase means the chance of developing breast cancer is still very low.

If you have symptoms of breast cancer – such as a hard, painless lump in one of your breasts – your GP will carefully examine you.

During the examination, they will also look for other possible signs of male breast cancer, such as swollen lymph nodes (glands).

It’s likely your GP will refer you for further tests if there is a possibility you may have breast cancer. These tests are described below.

Mammogram

A mammogram is a type of X-ray used to help determine whether there are any changes in breast tissue that could be the result of cancer.

During the mammogram procedure, a radiographer (a specialist in taking X-rays) will compress one of your breasts between two X-ray plates. This should not be painful, but you should tell the radiographer if you find it uncomfortable.

Once your breast has been correctly positioned, an X-ray will be taken which will produce a clear image of the inside of your breast. The procedure will then be carried out on your other breast.

Ultrasound

An ultrasound scan uses high frequency sound waves to produce an image of the inside of your breasts (in the same way that an unborn baby can be seen in the womb).

An ultrasound probe or sensor will be placed over your breasts to create an image of the inside of your breasts on a screen. The image will highlight any lumps or abnormalities that may be present in your breasts.

Biopsy

A biopsy may be recommended if a mammogram or ultrasound scan highlight any lumps or abnormalities in your breasts. A biopsy is a test that can either confirm or rule out a diagnosis of breast cancer in men. It involves taking a sample of suspected cancerous tissue and examining it in a laboratory for the presence of cancerous cells.

A type of biopsy known as a core biopsy is usually recommended for the diagnosis of breast cancer in men. This type of biopsy can usually indicate whether the cancer has started to spread from the breast into the surrounding area.

During a core biopsy, a local anaesthetic will be used to numb your breast. A hollow needle will then be used to remove a number of small tissue samples from the breast lump.

If cancer is found, it will also be possible to check whether there are special proteins, known as oestrogen receptors, on the surface of the cancerous cells. This is important because if oestrogen receptors are found (they are in around 90% of cases), it is possible to treat the cancer with hormone therapy. See treating breast cancer in men for more information.

Staging

After breast cancer has been diagnosed, your care team should provide information about the stage of the cancer. Staging is a system used to describe how far a cancer has spread at the point of the diagnosis.

A cure may be possible if breast cancer is diagnosed at an early stage. However, treatment can only be used to control symptoms and slow the spread of the cancer if it is diagnosed at a later stage. Unfortunately, more than 40% of breast cancers in men are diagnosed at a late stage.

In some cases, men are diagnosed with a type of breast cancer called ductal carcinoma in situ (DCIS). This means there are cancer cells in the breast, but they are contained within the breast ducts and cannot spread. If left untreated, DCIS can lead to invasive breast cancer.

Coping with a diagnosis

Being told you have breast cancer can cause a wide range of emotions, such as shock, fear, confusion and, in some cases, embarrassment.

Most people assume breast cancer only affects women, so it can be difficult to come to terms with the diagnosis.

Feelings of isolation and being alone are common in men with breast cancer. This may be because there is little in the way of advice and support for men with breast cancer, particularly when compared to the support available for women with the condition.

Sometimes, men who find themselves in this situation can become depressed. You may be depressed if during the past month you have felt very down and no longer interested in doing activities you used to enjoy. If you think you may be depressed, visit your GP. There are a range of effective treatments, such as medication and counselling, that can help relieve feelings of depression.

You may also find it useful to talk to other men affected by the condition. Breast Cancer Care is a breast cancer charity that provides an online forum for men diagnosed with breast cancer.

Breast cancer is often thought of as a condition that only affects women, but men can also develop it.

Breast cancer in men is much less common than breast cancer in women, affecting one in every 100,000 men in the UK.   

The cancer develops in the small amount of breast tissue men have behind their nipples. The most common symptom is a hard, painless lump in one of the breasts.

However, it is important to note that the vast majority of breast lumps are due to a condition called gynaecomastia. This is a common, non-cancerous condition where male breast tissue becomes enlarged.

Breast cancer in men can also cause nipple problems, such as the nipple turning in on itself (retraction) or nipple discharge.

Read more about the symptoms of male breast cancer.

When to see your GP

You should always talk to your GP if you notice a lump in your breast, or you have problems affecting your nipples, such as discharge.

While these symptoms are unlikely to be caused by breast cancer, they should be investigated further. 

Why it happens

The cause of male breast cancer is unclear, but factors known to increase your chances of developing the condition include:

• age – most cases affect men over 60 years of age
• having a family history of breast cancer (male or female)
• obesity – a body mass index (BMI) of 30 or more

Read more about causes of breast cancer in men.

Who is affected

Breast cancer is much rarer in men than women. Only about 1 in 1,000 men develop breast cancer in their lifetime.

Around 350-400 new cases of breast cancer are diagnosed in men in the UK every year. The condition is most often diagnosed in men aged 60-70.

Treating breast cancer in men

In most cases, surgery is used to remove the cancer along with a section of the breast. This is usually followed by a long-term course of hormone therapy using a medication called tamoxifen.

Tamoxifen helps to block the effects of hormones on breast tissue that are known to stimulate the growth of cancerous cells. It should help prevent the cancer from returning.

In some cases, radiotherapy or chemotherapy may be used for the same purpose.

Read more about treating breast cancer in men.

Outlook

The outlook for breast cancer is not as good in men as in women. This is because there is reduced awareness of the condition and it may take longer to diagnose.

The survival rates for breast cancer in men largely depend on how far the cancer has spread before it is diagnosed. Breast cancer diagnosed at an early stage can often be treated successfully, but effective treatment is more difficult if the cancer has spread beyond the breast tissue.

Unfortunately, many cases are diagnosed after the cancer has already started to spread.

Read more about diagnosing breast cancer in men.

The Map of Medicine is used by doctors throughout the NHS to determine the best treatment options for their patients. NHS Choices offers everyone in England exclusive and free access to this cutting-edge internet resource, which lets you see exactly what your doctor sees.

The information in the Map has been approved by the UK’s leading clinical experts, is based on the best available clinical evidence, and is continually updated. To take advantage of this unique resource go to:

Map of Medicine: breast disease

The main symptom of breast cancer in men is a hard lump in one of your breasts. The lump is almost always painless.

The lump is usually located underneath the nipple and areola (the circle of dark coloured skin surrounding the nipple).

However, it is important to note that the vast majority of breast lumps are due to a condition called gynaecomastia. This is a common, non-cancerous condition where male breast tissue becomes enlarged.

Less common symptoms of male breast cancer usually affect the nipple. These can include:

• the nipple begins to turn in on itself (nipple retraction)
• the nipple becomes hard, inflamed, and looks sore (nipple ulceration)
• fluid leaking from the nipple (nipple discharge)

Advanced symptoms

Additional symptoms usually only develop if the cancer spreads from your breast to other parts of the body, such as your bones, liver or lungs. This is known as metastatic breast cancer.

Symptoms of metastatic breast cancer include:

• bone pain
• swelling of the lymph nodes (glands), usually in or around the armpit
• shortness of breath
• feeling unusually tired all the time
• feeling sick (nausea)
• itchy skin with jaundice (yellowing of the skin and whites of the eyes)

When to seek medical advice

You should always visit your GP if you notice a lump in your breast or if you have problems affecting your nipples, such as retraction, ulceration or discharge. 

These problems are unlikely to be of the result of breast cancer, but they should be investigated further.

Treatment for breast cancer in men largely depends on how far the cancer has spread.

Most hospitals use multidisciplinary teams (MDTs) to treat men with breast cancer. These are teams of specialists who work together to make decisions about the best way to proceed with your treatment.

Deciding which treatment is best for you can often be confusing. Your cancer team will recommend what they think is the ideal treatment option but the final decision will be yours.

Before visiting hospital to discuss your treatment options, you may find it useful to write a list of questions you would like to ask the specialist. For example, you may want to find out the advantages and disadvantages of particular treatments.

Your treatment plan

Your recommended treatment plan will depend on how far the cancer has spread. If the cancer has not spread significantly beyond your breast, a complete cure may be possible.

In these cases, surgery to remove the affected breast is usually recommended. This is often followed by radiotherapy, hormone therapy and/or chemotherapy to help prevent the cancer returning.

If the cancer has spread beyond your breast into other parts of your body, such as your lungs, a complete cure will not be possible. However, hormone therapy and chemotherapy can be used to relieve symptoms and slow down the spread of the cancer.

More information about these treatments can be found below.

Surgery

Surgery is usually recommended as the first treatment for breast cancer. Specifically, this involves an operation called a mastectomy.

A mastectomy procedure involves the removal of the entire breast, often along with the nipple and lymph nodes (glands) in the armpit. In some cases, part of the muscle under the breast may also be removed if there is a risk the cancer has spread to this area.

Once surgery has been completed there will be a straight scar across your chest where your nipple used to be and possibly an indentation around that area where the breast tissue used to be.

After surgery

Most men are well enough to leave hospital one to three days after surgery. After the operation, it’s likely you will feel very tired and it may take a few weeks before you are well enough to start carrying out relatively strenuous activities, such as lifting objects or driving. Your MDT specialist nurse will be able to offer more specific advice about this.

The wound will take about two to three weeks to heal. It is important to keep the wound clean during this time. You should look for any signs that the wound may have become infected, such as redness and swelling around the wound or a discharge of pus. Inform your MDT as soon as possible if you suspect an infection.

It’s difficult to predict when you will feel able to return to work. Some people choose to remain off work until other treatments, such as radiotherapy, have been completed. Others prefer to return to work in between treatments. Your MDT will be able to advise you, but the final decision will be yours.

It can take several weeks to fully recover from the effects of a mastectomy. A structured exercise programme, where the intensity and amount of time spent exercising is gradually increased, will probably be recommended.

Your MDT will be able to provide you with more advice or refer you to a physiotherapist (a specialist with training in rehabilitation using exercise).

The Royal College of Surgeons have produced a useful leaflet for people who are recovering after having a mastectomy (PDF, 363kb).

Complications of surgery

Following surgery, you may experience numbness or tingling at the site of the scar and in your upper arm. This is common and caused by nerve damage during surgery. The numbness and tingling should pass within a few weeks or months, although it can occasionally be permanent.

Another common complication is painful swelling in the arms and legs and, sometimes in other parts of the body, such as the head and chest. This is called lymphoedema and it is caused by the disruption of the lymphatic system (a series of channels and lymph nodes which is normally responsible for removing excess fluid from tissue).

If multiple lymph nodes (glands) are surgically removed it can disrupt the lymphatic system’s ability to drain fluid which can lead to swelling.

There is no cure for lymphoedema, but it is possible to control the symptoms using a combination of different techniques, such as massage and compression garments. See treating lymphoedema for more information.

Radiotherapy

Radiotherapy is a type of treatment involving a machine that releases high energy waves to destroy cancerous cells. It can be given a few weeks after surgery to prevent the cancerous cells returning.

A typical course of radiotherapy involves two to five sessions a week over the course of three to six weeks. The sessions are short and usually only last for 10 to 15 minutes.

Radiotherapy is not usually painful although you will probably experience some side effects. This is because the energy released during radiotherapy can also damage healthy cells.

Common side effects of radiotherapy can include:

• extreme tiredness (fatigue)
• feeling sick (nausea)
• sore, red, and irritated skin on the breast (similar in appearance to sunburn)

The side effects of radiotherapy should pass after your course of treatment has finished, although some men experience prolonged fatigue for several months.

Radiotherapy can also be used in cases of advanced breast cancer to slow down the spread of the cancer and relieve the symptoms of pain. This is known as palliative radiotherapy. Palliative radiotherapy is usually given in just one or two doses and does not usually cause any side effects.

Hormone therapy

About 90% of cases of breast cancers in men are oestrogen receptor positive or ER+ (E is used because the American spelling of oestrogen is ‘estrogen’). This means the cancerous cells require oestrogen to grow. Oestrogen is a type of hormone found in low levels in men and in much higher levels in women.

The aim of hormone therapy is to block the effects of oestrogen on the breast tissue to prevent the cancer reoccurring after surgery. It can also be used in cases of advanced breast cancer to slow down the spread of the cancer.

Tamoxifen

Tamoxifen is a hormone medication widely used for breast cancer. It is available in tablet or liquid form and prevents oestrogen from entering the breast tissue cells.

However, the ideal length of treatment with tamoxifen is unclear. Studies in women with breast cancer suggest a five year course of treatment is the most effective in preventing the return of cancer and extending survival rates. However, it is unclear if this also applies to men.

Tamoxifen can also cause unpleasant side effects, which will be taken into consideration when your MDT is deciding which treatments to recommend. You can discuss the pros and cons of long-term treatment with tamoxifen with your MDT.

Side effects of tamoxifen can include:

• reduced interest in sex (loss of libido)
• inability to obtain or maintain an erection (erectile dysfunction)
• headache
• feeling sick, although taking your medication with food may help to reduce this side effect
• changes in mood, such as feeling irritable or depressed

You should inform your MDT if you experience side effects that become particularly troublesome, as alternative medications are available.

Aromatase inhibitors

Aromatase inhibitors are an alternative type of hormone medication. They may be used if tamoxifen proves unsuccessful or if the side effects of tamoxifen are particularly troublesome. Aromatase inhibitors can also be used to slow the spread of advanced breast cancer.

In men, oestrogen is created when a protein called aromatase converts another hormone called androgens. Aromatase inhibitors block the effects of aromatase which, in turn, lowers the amount of oestrogen in the body.

Aromatase inhibitors are usually given in tablet form and taken daily for two to five years. As with tamoxifen, there is little available evidence (compared with female breast cancer) regarding the most effective length of dosage.

Side effects of aromatase inhibitors can include:

• joint pain
• lack of energy
• hot flushes
• skin rashes
• feeling sick
• being sick
• thinning of the hair

However, it’s unlikely you will experience all of these.

Chemotherapy

Chemotherapy is used to treat cases of breast cancer where hormone therapy would be largely ineffective because the cancerous cells are not oestrogen receptor positive (ER+). It’s usually given after surgery to help prevent the cancer returning or it’s used to treat the symptoms of incurable cancer.

Chemotherapy for breast cancer involves taking a combination of cancer-killing medications. Treatment is usually given every two to three weeks, over the course of six months.

You may be given chemotherapy tablets (oral chemotherapy), chemotherapy injections (intravenous chemotherapy) or a combination of both.

The side effects of chemotherapy can include:

• feeling sick
• being sick
• diarrhoea
• loss of appetite
• mouth ulcers
• tiredness
• skin rashes
• infertility
  
• hair loss

However, the side effects should resolve once your treatment has finished. Following treatment, your hair should grow back after about three to six months.

Chemotherapy can also weaken your immune system, making you more vulnerable to infection. It is therefore important to report any symptoms of a potential infection to your MDT such as:

• a high temperature of 38^oC (100.4^oF) or above
• flu-like symptoms, such chills or joint pain
• a general sense of feeling unwell

You should also avoid close contact with people known to have an infection.

If you are sexually active, you should use a condom for 48 hours after receiving a dose of chemotherapy medication. This is because the medication used in chemotherapy could pass into your semen and cause irritation in the tissue of your partner’s genitals.

You should avoid having children while receiving chemotherapy because many of the medications can damage your sperm and increase your chances of having a baby with a birth defect. Again, using a reliable method of contraception, such as a condom, is recommended

Depending on the medications used, it may be several months after your course of chemotherapy has ended before you can safely have children. Your MDT will be able to give you a more detailed recommendation.

Biological therapy

Biological therapy uses medication to block the effects of a protein called human epidermal growth factor receptor 2 (HER2) in cases where HER2 is contributing to breast cancer.

Biological therapies are sometimes referred to as targeted therapies because they are designed to target biological processes that cancers rely on to grow and reproduce.

If you have high levels of the HER2 protein and are able to have biological therapy, you will probably be prescribed a medicine called trastuzumab. Trastuzumab, also known by the brand name Herceptin, is usually used after radiotherapy or chemotherapy to prevent cancerous cells returning.

Trastuzumab

Trastuzumab is a type of biological therapy known as a monoclonal antibody. Antibodies occur naturally in the body and are created by the immune system to destroy harmful cells, such as viruses and bacteria. The trastuzumab antibody targets and destroys cancer cells designed to respond to the HER2 protein.

Trastuzumab is given intravenously (through a drip, directly into a vein). You will receive the treatment in hospital. Each treatment session takes up to one hour and the number of sessions you need will depend on whether your breast cancer is in its early or more advanced stages. On average, for early breast cancer you will need to have a session once every three weeks, and for more advanced cancer you will need to have weekly sessions.

Trastuzumab can cause side effects, including heart problems. This means that it is not suitable if you have a heart problem, such as angina, uncontrolled high blood pressure (hypertension), or heart valve disease. If you need to take trastuzumab, you will need to have regular tests on your heart to ensure it is not causing any problems.

Other side effects of trastuzumab can include:

• an initial allergic reaction to the medication, which can cause nausea, wheezing, chills and fever
• diarrhoea
• tiredness
• aches and pains

When John found a lump in his breast, he had no idea it was a sign of cancer. He tells us his story.

“My wife and I were a bit concerned when we discovered a lump in my breast, so we went to the doctor. He said it was probably scar tissue caused by contact sports (I’d done a lot of judo in the past).

“Around that time, I also noticed that my nipple had become inverted. It didn’t worry me – I just thought it was something that happened when you get older and a bit overweight.

“A couple of years later, my wife read that an inverted nipple could be a sign of breast cancer. We phoned her cousin, who’s a GP, and she told us to get it checked out. So we went back to my GP and I ended up having a needle biopsy. Surprisingly, it showed that I had breast cancer.

“Things happened very quickly after that. The following week, I was in hospital having a mastectomy (breast removal). While surgeons were removing the breast, they noticed that the lymph glands were cancerous too, so they removed some of them from under my arm. The operation was straightforward and almost painless afterwards. I was released on the Saturday morning and went back to work on Monday.

“Then, a few months after the operation, I started chemotherapy. This was the real killer. It made me feel queasy all the time. I got really grumpy, and was shouting at everyone. I had it once a week, for six months, followed by a course of radiotherapy.

“After the radiotherapy, they put me on a breast cancer drug called Arimidex (anastrozole) for five years. It’s the same treatment for men as it is for women. My joints and muscles ached when I was on this medication, but these side effects disappear after you finish the course.

“I don’t know what caused my breast cancer, although I’ve heard it can be hereditary, and my late mother had breast cancer. I’m alright now, and my life is back to normal.

“The doctors got rid of my cancer just in time; I was very lucky. I couldn’t fault the NHS. All the staff were superb. Even when I was going through chemotherapy and getting grumpy with everyone, they understood and weren’t offended.”