What is breast cancer?

Clinical oncologist, Bernadette Lavery, talks you through what breast cancer is, the main types, risk factors, stages and common treatments available to you.


Breast cancer in men is rare. About 390 men in the UK are diagnosed with breast cancer each year. Men have a small amount of breast tissue behind their nipples, where breast cancer can develop.

Types of breast cancer in men

There are different types of breast cancer. Knowing the type you have helps your doctors decide on the best treatment for you.

Most breast cancers in men are invasive. This means the cancer cells have spread outside the lining of the ducts of the breast and into surrounding breast tissue. There are two main types:

  • No special type
    This is the most common type of invasive breast cancer. About 7 to 9 out of 10 breast cancers in men (70% to 90%) are this type. This is when cancer cells are examined under the microscope and they have no specific features. They are called breast cancer of ‘no special type’ (NST) or ‘not otherwise specified’ (NOS).
  • Special types
    Some cells have features that identify them as a specific type of breast cancer. These are called ‘special type’ breast cancers. They are named depending on how the cells look under a microscope. The types include tubular, medullary, mucinous and cribriform.

Ductal carcinoma in situ (DCIS) is the earliest form of breast cancer. In DCIS there are cancer cells in the ducts of the breast, but these cells are contained (in situ). They have not spread into normal breast tissue. It is much less common in men than in women. Less than 1 in 10 breast cancers in men (10%) are DCIS.

There are other types of invasive breast cancer, including Paget's disease and inflammatory breast cancer, but these are very rare in men.


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Booklets and resources

Breast cancer symptoms in men

The first symptom of breast cancer that men may notice is a painless lump under the nipple or areola.

If you are worried, we have more information about the signs and symptoms of breast cancer in men.

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Causes of breast cancer in men

Doctors do not know the exact causes of breast cancer. But there are risk factors that can increase your chance of developing it.

Because breast cancer in men is rare, most men who have these risk factors will never develop it.

Diagnosis of breast cancer in men

You usually start by seeing your GP. They will examine you and refer you to a breast clinic. You should get an appointment within 2 weeks.

At the breast clinic

You will see a specialist breast doctor or a nurse practitioner. You may also see a breast care nurse. They usually ask you if:

  • you have had any other breast problems
  • you have a family history of breast cancer.

The doctor or nurse will examine your breast and the lymph nodes in your armpits and around your neck.


After your examination, your doctor or nurse will tell you what tests you need:

  • Breast ultrasound

    An ultrasound uses sound-waves to build up a picture of the breast tissue. A gel is spread onto the area and a small device is moved across it. You may also have an ultrasound scan of the lymph nodes in the armpit. If any of the nodes feel swollen or look abnormal on the ultrasound, the doctor will take a biopsy of them.

  • Mammogram

    A mammogram is a low-dose x-ray of the breast.

  • Breast biopsy

    There are different ways you may have a biopsy. The doctor removes a small piece of tissue or a sample of cells from the lump or abnormal area. The sample is then checked for cancer cells.

You may have many of these tests on the same day, as well as getting the results. But you might have to wait up to 2 weeks for some results. We have more information on waiting for test results.

Further tests after diagnosis

If the biopsy results show there are breast cancer cells, you will need further tests.

You may have the following tests to check your general health:

  • Blood test

    You have a blood test to check your general health and how well your kidneys and liver are working.

  • Chest x-ray

    You will have a chest x-ray to check your lungs and heart.

You may also have the following tests to find out more about the size and position (stage) of the cancer:

  • MRI (magnetic resonance imaging) scan

    An MRI scan uses magnetism to build up detailed pictures of your body.

  • Bone scan

    A bone scan shows up abnormal areas of bone. You have a small amount of a radioactive substance injected into a vein. The amount of radioactive substance used is small. After 24 hours, your body will have got rid of the radioactivity in your urine.

  • CT scan

    A CT scan takes a series of x-rays, which build up a three-dimensional picture of the inside of the body.

  • Liver ultrasound

    An ultrasound uses sound-waves to build up a picture of the liver.

Staging and grading of breast cancer in men

The stage of cancer describes its size and how far it has spread, based on your test results.

A doctor decides the grade by how the cancer cells look under the microscope. This gives an idea of how quickly the cancer might grow or spread.

You and your doctors can then talk about the best treatment choices for you.

Receptors for breast cancer in men

Breast cancer cells may have receptors (proteins) that hormones or a protein called HER2 can attach to. These receptors encourage the cancer cells to grow. They are found through the biopsy.

There are different types of receptors. In breast cancer, we talk about:

  • Hormone receptors
    All men have small amounts of the hormones oestrogen and progesterone in their bodies. Breast cancer that has receptors for the hormone oestrogen is called oestrogen receptor-positive (ER-positive) breast cancer. Most breast cancers in men are ER positive.
  • Receptors for HER2
    Some breast cancers have too much of a protein (receptor) called HER2 (human epidermal growth factor receptor 2) on the surface of their cells. This is called HER2-positive breast cancer.

Cancer that does not have receptors for either HER2 or the hormones oestrogen and progesterone is called triple negative breast cancer.

Treatment for breast cancer in men

A team of specialists will meet to discuss the best possible treatment for you. This is called a multidisciplinary team (MDT).

Your doctor will explain the different treatments and their side effects. They will also talk to you about the things you should consider when making treatment decisions.

For most men, the main treatment for early breast cancer is surgery to remove the cancer. You may have:

  • A mastectomy

    A mastectomy is when the whole breast is removed.

  • Breast-conserving surgery (wide local excision)

    This is where the cancer and some surrounding normal breast tissue is removed.

Your surgeon may remove some or all the lymph nodes in your armpit. Or you may be offered radiotherapy to the lymph nodes instead.

If you have locally advanced breast cancer or inflammatory breast cancer you will usually be offered chemotherapy or sometimes targeted therapy before surgery. This is known as neo-adjuvant treatment.

We have more information about having your operation. You may also need support when dealing with changes to your body after surgery.

Adjuvant treatments

Adjuvant treatment is treatment you have after surgery. Your cancer doctor will usually offer you one or more of the following treatments:

  • Radiotherapy

    Radiotherapy uses high-energy rays. You may have it to the chest wall after surgery. Some men may also have radiotherapy to the lymph nodes in the armpit or the lower part of the neck.

  • Chemotherapy

    Chemotherapy uses different drugs to treat breast cancer. It is most commonly given as an injection into a vein or as tablets or capsules.

  • Targeted therapy

    Targeted therapies interfere with the way cells grow. They can reduce the risk of HER2 breast cancer coming back.

  • Hormonal therapy

    Hormonal therapy can slow down or prevent breast cancer cells from growing in men who have ER positive breast cancer.

After breast cancer treatment


As part of your follow-up treatment, you may have routine appointments with your doctor or breast care nurse, or they may give you information on what to look out for.

The treated side of your chest will look and feel different. It is important to get to know these changes so you can notice anything unusual between appointments. If this happens you should contact your cancer specialist or breast care nurse straight away.

You may get anxious between appointments. This is natural. It may help to get support from family, friends or a support organisation. 

Macmillan is also here to support you. If you would like to talk, you can: 


Lymphoedema is a swelling of the arm or hand. It sometimes happens after surgery or radiotherapy to the lymph nodes in the armpit. It usually develops slowly, months or years after treatment.

There are things you can do to help reduce your chances of developing lymphoedema. If you notice any swelling in your arm, hand or chest, always ask your doctor or nurse to check it.

Sex life and fertility

Breast cancer treatments can have a direct effect on your sex life and ability to have children (fertility). Talk to your doctor or breast care nurse, there are often things that can help.

You may have a loss of sex drive (libido) and erection difficulties (erectile dysfunction or ED). This often improves after treatment, but it may take longer or become permanent. If you have a partner, it is important to talk to them. You may both need some time to adjust.

Some treatments can reduce the number of sperm you produce or make you infertile. It may be possible to store sperm before treatment begins. Fertility and sexual issues can hard to cope with. You may find it helpful to talk through your feelings with your doctor, breast care nurse, or a trained counsellor.

It is important to use effective contraception while having chemotherapy and for some time afterwards. Chemotherapy drugs in a man’s sperm may harm a developing baby.

Well-being and recovery

Even if you already have a healthy lifestyle, you may choose to make some positive lifestyle changes after treatment.

Making small changes to the way you live such as eating well and keeping active can improve your health and well-being and help your body recover.


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About our information

  • References

    Below is a sample of the sources used in our breast cancer in men information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    European Society for Medical Oncology. Primary breast cancer: ESMO clinical practice guidelines for diagnosis, treatment and follow-up. Annals of oncology 26 (supplement 5): v8–v30. 2015. 

    Gradishar WJ, et al. Breast cancer in men. UpToDate online. June 2018.

    Morrow M, et al. Chapter 79: malignant tumors of the breast. DeVita, Hellman and Rosenberg’s cancer: principals and practice of oncology (10th edition). Lippincott Williams and Wilkins. 2014.

    National Institute for Health and Care Excellence (NICE). Early and locally advanced breast cancer: diagnosis and management. July 2018.

    National Institute for Health and Care Excellence (NICE). Advanced breast cancer: diagnosis and treatment. Clinical Guideline 81. February 2009, updated August 2017. 

    Scottish Intercollegiate Guidelines Network. SIGN 134. Treatment of primary breast cancer: a national clinical guideline. September 2013.


  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editors, Dr Rebecca Roylance, Consultant Medical Oncologist; and Dr Mark Verrill, Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

Reviewed: 31 October 2018
Reviewed: 31/10/2018
Next review: 30 April 2021
Next review: 30/04/2021

This content is currently being reviewed. New information will be coming soon.