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.


Each year, about 55,000 women are diagnosed with breast cancer in the UK. It is more common in women who are aged 50 and over.

Breast cancer can be invasive or non-invasive (in-situ). When people talk about breast cancer, they usually mean invasive breast cancer. This is when cancer cells have spread outside the milk ducts or lobules where they started into surrounding breast tissue.

We have information about non-invasive breast cancer called ductal carcinoma in situ (DCIS). It is the earliest possible form of breast cancer and is usually found during routine breast screening.

Breast cancer in men is rare. We have more information for men with breast cancer.

Booklets and resources

Types of breast cancer

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 are invasive and there are different types. They start in the ducts or lobes of the breast and spread into surrounding breast tissue. Breast cancer that has not spread outside the lobes or ducts is called ductal carcinoma in situ (DCIS). It is the earliest possible form of breast cancer. It needs to be treated but is not life-threatening.

Invasive breast cancers can be grouped depending on how the cells look when they are examined under the microscope. The most common type of invasive breast cancer is ductal invasive. Invasive lobular breast cancer is a much less common type. Some other rarer types are:

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Symptoms of breast cancer

Listen to Bami talk about the importance of checking your breasts and knowing what is normal for you.

A breast lump is the most common symptom of breast cancer. Most breast lumps are not cancer but it is always important to get checked by your doctor.

If you have any symptoms or do a self-exam and notice anything that is unusual for you see your GP straightaway.

Causes of breast cancer

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

Having one or more risk factors does not mean you will get breast cancer. Also, having no risk factors does not mean you will not develop it.

Breast cancer is likely to be caused by a combination of different risk factors, rather than just one.

Diagnosis of breast cancer

Women who have symptoms usually begin by seeing their GP. They will examine you and refer you to a breast clinic. You should get an appointment within 2 weeks.

Some women are referred through the NHS breast screening programme. Breast screening is a way of finding breast cancer at an early stage, when it is too small to be felt or seen.

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 breasts 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:

  • Mammogram

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

  • Breast ultrasound

    A breast ultrasound uses sound-waves to build up a picture of the breast tissue. You will also have an ultrasound scan of the lymph nodes in the armpit.

  • Breast biopsy

    During a breast biopsy, the doctor removes a small piece of tissue or cells from the lump or abnormal area. The sample is checked for cancer cells. There are different ways of taking a breast biopsy.

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 have tests to find out more about the size of the cancer, or if it has spread anywhere else in the body (its stage):

  • MRI (magnetic resonance imaging) scan

    An MRI scan uses magnetism to build up detailed pictures of your body. It may be done to find out the size of the cancer and help decide on the operation you have.

  • CT scan

    A CT scan takes a series of x-rays, which build up a three-dimensional picture of the inside of the 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 and wait for 2 to 3 hours to have the scan.

Staging and grading of breast cancer

The results of your tests help your doctors find out more about the size and position of the cancer and whether it has spread. This is called staging.

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

Knowing the stage and grade helps your doctors plan the best treatment for you.

This information is about stage 1 to 3 breast cancer. If you have stage 4 breast cancer, you may find our information about secondary breast cancer helpful.

Receptors for breast cancer

Breast cancer cells may have receptors (proteins) that hormones or a protein called HER2 can attach to and encourage the cells to grow. Cancer cells taken during biopsy are tested for these receptors.

There are different types of receptors in breast cancer:

  • Hormone receptors

    Breast cancer that has receptors for the hormone oestrogen is called oestrogen receptor-positive (ER-positive) breast cancer.

  • 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 hormones or HER2 is called triple negative breast cancer.

Treatment for breast cancer

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 treatment options and their side effects. They will also talk to you about the things you should consider when making treatment decisions.

The first treatment for breast cancer is often surgery to remove it. Your surgeon will talk to you about having one of these operations:

  • Breast-conserving surgery

    Breast-conserving surgery is when the cancer and some surrounding normal breast tissue is removed.

  • Mastectomy

    A mastectomy is when the whole breast is removed.

You will usually need some, or all, of the lymph nodes in your armpit removed.

Some women may be asked to decide if they want surgery to make a new breast shape (breast reconstruction) during the operation. Others may decide to have this done later.

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

Treatment before surgery

Some women may have treatment, such as chemotherapy or hormonal therapy, before surgery. This is called neo-adjuvant treatment.

It may be given to shrink a larger cancer. Doctors may give you neo-adjuvant treatment so you can have breast-conserving surgery instead of a mastectomy. Or you have chemotherapy before surgery with certain types of breast cancer or when the cancer is growing more quickly. This is given to reduce the risk of the cancer coming back.

Treatment after surgery

Your cancer doctor will usually offer you one or more of the following treatments after surgery to reduce the risk of breast cancer coming back:

  • Radiotherapy

    Radiotherapy uses high-energy rays. You have it after breast conserving surgery and sometimes after a mastectomy.

  • Chemotherapy

    Chemotherapy uses different drugs to treat breast cancer. You usually have it as an injection into a vein or sometimes as tablets.

  • Hormonal therapy

    Hormonal therapy reduces the amount of oestrogen in the body. It can prevent breast cancer cells from growing in women who have ER positive breast cancer.

  • Targeted therapy

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

  • Bisphosphonates

    Bisphosphonates are drugs that help to protect the bones against some effects of breast cancer treatments. They can also help reduce the risk of breast cancer spreading to the bones.

We have more information in our treatment overview.

After breast cancer treatment


As part of your follow-up after treatment, you will have yearly mammograms every year for 5 years.

You may have routine appointments with your doctor or breast care nurse, or they may give you information on what to look out for.

Your treated breast will look and feel different. If you notice anything unusual between appointments, 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. In younger women some treatments may also affect being able to get pregnant (fertility).

For example, surgery may affect how you think and feel about your body (body image) which can affect your sex life. It can take time to adjust to changes to your body. If you have a partner, it can help to talk openly with them about your feelings. If any difficulties do not improve, ask your breast care nurse or doctor for advice.

If you have not been through menopause your doctor or nurse will advise you not to use contraception containing hormones. Women thinking of getting pregnant in the future will usually be advised to wait for 2 years.

If doctors think your treatment may affect your fertility, it may be possible to remove eggs from your ovaries before treatment starts. This may mean you can have fertility treatment in the future.

Fertility issues can hard to cope with. Some women may find it helpful to talk to a trained counsellor.

Early menopause

Some treatments can cause permanent or temporary menopause, which can cause different symptoms. It can increase your risk of bone thinning (osteoporosis).

Doctors do not usually recommend hormone replacement therapy (HRT) after breast cancer. But there are different ways of managing menopausal symptoms and looking after your bone health.

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.

Related pages

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About our information

  • References

    Below is a sample of the sources used in our breast cancer 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.

    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.

    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 Editor, Dr Rebecca Roylance, 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.

Date reviewed

Reviewed: 31 October 2018
Next review: 30 April 2021

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

Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.