Glossary for breast cancer related words and descriptions

You'll find many commonly used breast cancer terms across the Breast Cancer Now website. This glossary will help you to understand what they mean.

Click one of the letters above to advance the page to terms beginning with that letter.


Adjuvant treatment

Any additional treatment given after the main treatment, which is usually surgery. Adjuvant treatment is given to people with primary breast cancer to reduce the risk of cancer returning and/or spreading from the breast and can include radiotherapy, chemotherapy, anti-hormone therapy or targeted therapy.

Read more on our treating breast cancer page.

Advanced breast cancer

This term refers to breast cancer that has spread from the breast to other parts of the body. Depending on how far the cancer has spread, advanced breast cancer can be either "locally advanced" or metastatic. Locally advanced breast cancer is diagnosed if the breast tumour is larger than 5cm, or if it has spread to the skin or the front of the chest.

The lymph nodes under the armpit might also be affected. If the cancer has spread further into the body, for example to the liver or bone, this is known as metastatic or secondary breast cancer. The tumours in sites other than the breast are known as metastases (plural of metastasis), which is sometimes abbreviated to "mets".

Aggressive cancer

Cancer that is growing quickly.


A lower than normal number of red blood cells (or reduction in haemoglobin in the blood). This reduces the amount of oxygen the blood can carry, leading to symptoms such as tiredness and a lack of energy.

Anastrozole (Arimidex)

A type of aromatase inhibitor.


A group of chemotherapy drugs, includes doxorubicin and epirubicin.

Anti-hormone therapy

Sometimes referred to as "hormone therapy", this is a way of treating breast cancer by blocking the effect of hormones, such as oestrogen. Some breast cancers are stimulated to grow by oestrogen so drugs such as tamoxifen or aromatase inhibitors are given to block the effects of oestrogen.

Aromatase inhibitor

An aromatase inhibitor (AI) is a type of anti-hormone therapy that blocks the production of oestrogen in the body. It is used to treat hormone-positive breast cancers, which are defined by the cancer cells having high levels of the oestrogen and / or progesterone receptors. An AI is often used as an alternative to tamoxifen and includes the drugs anastrozole, letrozole or exemestane.


Also known as bevacizumab, Avastin is a targeted therapy that works by blocking the formation of new blood vessels which allow cancer cells to continue growing, a process called anti-angiogenesis.


A medical term for the armpit.

Axillary clearance

The removal of all the lymph nodes from the armpit.

Axillary node sampling

The removal of a few lymph nodes from the armpit to test them for the presence of cancer.


Benign tumour

A benign tumour or growth cannot spread through the body and may be slow growing. It is not cancerous.

Bilateral mastectomy

A bilateral mastectomy is a surgical procedure in which both of the breasts are removed.


A biopsy involves removing some tissue from the body so that the cells can be inspected under a microscope to see if they are normal or cancerous and to identify other features, such as whether the cancer cells are stimulated to grow by oestrogen (a hormone receptor positive cancer).


BRCA1 is a gene carried by all people, but people who have a mutation (fault) in this gene have a higher risk of developing breast and ovarian cancer. These people are most likely to have inherited the mutation from one of their parents. On average, a woman with a BRCA1 mutation has a 55% chance of developing breast cancer by the age of 70.


BRCA2 is a gene carried by all people, but people who have a mutation (fault) in this gene have a higher risk of developing breast and ovarian cancer. These people are most likely to have inherited the mutation from one of their parents. On average, a woman with a BRCA2 mutation has a 47% chance of developing breast cancer by the age of 70.

Breast Cancer Awareness Month (BCAM)

Breast cancer awareness month takes place every October around the world. October gives us the opportunity to raise awareness of breast cancer, encourage people to check their breasts and ask people to buy products or take part in an event such as wear it pink, to help raise money for breast cancer research.

Breast care team

A team of specialists, including doctors and nurses, responsible for the care of a patient with breast cancer.

Breast density

Breast density refers to the amount of fibrous and glandular tissue compared with fatty tissue in the breast. A woman has high breast density when there is more collagen and glandular tissue compared to fatty tissue in her breasts, and low breast density when there is more fatty tissue compared to glandular tissue and collagen.

Breast prosthesis

An artificial breast (commonly put in a bra pocket or stuck directly to the skin).

Breast reconstruction

Surgery to rebuild a breast after a tumour is removed.

Breast-conserving surgery

Breast-conserving surgery, also known as a lumpectomy or wide-local excision, is a type of surgery where the tumour is removed along with a margin (border) of normal breast tissue around it. The aim is to safely minimise the amount of breast tissue removed, which has the benefit of protecting the cosmetic appearance of the breast, compared to mastectomy.



A medical term for cancer: most common cancers, and all breast cancers are carcinomas. Other cancer types include leukaemia, lymphoma and sarcoma.


Chemoprevention is a way to reduce the risk of a disease by taking medication. The drugs tamoxifen and raloxifene are now available on the NHS for some women with an increased risk of developing breast cancer.


The use of chemical substances to treat disease by killing fast growing cells in the body, such as cancer cells. Chemotherapy drugs are often used in combination, and the drugs given, and the way they are given will differ according to the situation of the person being treated. For example, the FEC regime of chemotherapy, often used to treat breast cancer, consists of the drugs fluorouracil (also known as 5FU), epirubicin and cyclophosphamide

Clear margin

See 'Uninvolved margin'.

Clinical nurse specialist

A clinical nurse specialist has extra training to specialise in a particular area of care. For all breast cancer patients a clinical nurse specialist should be available to provide information, advice and support in the hospital and help with information on, contacting and arranging other services outside of the hospital.

Complex decongestive therapy (CDT)

A form of treatment for lymphoedema that aims to reduce swelling or to prevent the condition worsening.


A condition or circumstance that indicates that a particular medicine or treatment is not suitable for a particular person to receive.

Core biopsy

The removal of tissue using a needle to examine in the laboratory to check for cancer cells. See also biopsy.

CT or CAT scan

Short for Computerised Tomography Scan and also called a CAT scan. It is a type of scan similar to an X-ray, where multiple pictures are taken across the body, which enable doctors to look at images of ‘slices’ through the patient.


An expert in diagnosing disease by studying cells.


Substances that are toxic (poisonous) to cells, either stopping them from dividing into new cells or killing them.


Ductal Carcinoma In Situ (DCIS)

DCIS stands for Ductal Carcinoma In Situ. When we talk about breast cancer this usually means tumours that grow into the surrounding breast tissue, called 'invasive breast cancer'. However, sometimes cancerous changes develop within the lobules or ducts of the breast and do not break out into the surrounding tissue. DCIS refers to 'non-invasive' cancerous changes that are contained within the ducts.


Early breast cancer

Cancer in the breast that has not spread beyond the breast and armpit lymph nodes.

Endocrine therapy

See 'Anti-hormone therapy'.


Epigenetics refers to the study of epigenetic changes to the body's genetic material (DNA). These are molecular changes which tell the cell how the genes should be read. It might be easier to imagine as if the DNA code is the script of a play, epigenetics are like notes in the margin telling the actor or director how to interpret and enact that script.

Estrogen Receptor (ER)

See 'Oestrogen Receptor'.

Exemestane (Aromasin)

A type of aromatase inhibitor.


Fellowship grant

Breast Cancer Now’s Fellowship grants are designed to enable post-doctoral scientists to become independent researchers specialising in the breast cancer field and to undertake research of a high quality. Each Fellowship runs for five years and is an award of up to £550,000. Fellowships are awarded to scientists with a proven track record in the field of breast cancer research who wish to build on their history and reputation in this area, deepening their knowledge and experience. A Fellowship allows a scientist to become an independent and competitive researcher and allows Breast Cancer Now to ensure the continued strength of breast cancer research in the UK and Ireland.

Find out about applying for a breast cancer research grant


Thickening or scarring of connective tissue.

Fine Needle Aspiration (FNA)

To help make a breast cancer diagnosis, or to be able to look at cells without having to remove the whole tumour, doctors might perform a Fine Needle Aspiration – this is where cells are removed from the tumour using a very thin needle and syringe. Cells can then be taken from the needle and studied under the microscope.

Fractions (in radiotherapy)

Patients undergoing radiotherapy will receive a total dose of radiation which is split over several visits. The treatment given in each individual visit is referred to as a fraction. Splitting the total dose into fractions in this way allows normal cells to recover, whereas the cancer cells are less able to do so. Patients may receive fractions of radiotherapy across several days or weeks.



A gene is a length of DNA or genetic code which contains the necessary instructions for cells to make one particular protein. Cells then use these proteins to carry out a huge range of functions around the body, for example growth, repair, and reproduction; just about everything in fact. We inherit a unique combination of genes from each of our parents.

Genetic Testing

People who have a significant history of breast cancer in the family may be offered the option of having a blood test to see if they have a mutated or faulty gene that is linked to the breast cancer in their family. For more on the types of tests and who they are available to see our family history and breast cancer pages.


Breast cancers are graded on a scale of 1 to 3 to define how different they look under the microscope and how fast growing they are compared with normal breast cells, with 3 being the most different to normal cells.

Find out more about breast cancer grades


The money given to researchers to cover the cost of their work and sometimes their salary. Grants given by Breast Cancer Now range from thousands to half a million pounds, depending on the type of grant given (pilot, project, PhD, and fellowship) and the amount needed by researchers.

Find out how to apply for a research grant

Grants Committee

Our Grants Committee is made up of prominent breast cancer experts and supported by the advice of hundreds of scientists and doctors, and exists to ensure that the research the charity funds is of the highest calibre and will further our knowledge of breast cancer with the potential to benefit patients – whether in the short or long term. The Grants Committee meets twice a year to discuss and score the grant applications made by scientists to Breast Cancer Now.


A unit of measurement for radiotherapy doses.



Also known as trastuzumab. A drug used to treat HER2 positive breast cancers. Herceptin blocks the growth signals sent from HER2 receptors to stop cells from growing. Because it works by targeting the HER2 protein on cells it is known as a targeted therapy. Herceptin is a type of drug called a monoclonal antibody, meaning that the targeting part of each Herceptin molecule uses the same method as antibodies in the immune system to locate and target HER2 proteins in breast cancer cells.

Hormone positive breast cancer

Also known as hormone sensitive breast cancer, these breast cancers are stimulated to grow by hormones in the body. These breast cancers (about three out of four breast cancers) may be treated with hormone therapy, often in addition to other treatments.

Hormone Replacement Therapy (HRT)

Short for hormone replacement therapy. This is a type of treatment in which hormones are taken to help control the symptoms of the menopause. The hormones can be either oestrogen or a combination of oestrogen and progesterone.


Naturally occurring substances in the body that control the growth or activity of cells in the body.

Human Epidermal growth factor Receptor 2 (HER2)

HER2 stands for Human Epidermal growth factor Receptor 2, which is a protein found in many cells around the body and made by cells using the instructions within a gene called the HER2 gene. It is involved in helping cells to grow and in around 20 per cent of breast cancers it helps the cancer cells to grow more quickly because the cells have a lot of HER2 receptors. These breast cancers are classified as being ‘HER2 positive’ (HER2+). Drugs such as Herceptin (trastuzumab) work by blocking the growth signals from HER2 receptors.



Techniques, including mammography, that allow doctors to get a detailed picture of internal body structures.

Immune response

This is the mechanism the body uses to protect itself from foreign bodies that might be harmful, such as bacterial infections, or to destroy damaged or faulty cells that might cause harm to the body.


Incidence refers to how many people are diagnosed with a disease per year. It can be expressed as a number or as a rate, for example the number of people diagnosed per 100,000 of a population.

Inflammatory breast cancer

Inflammatory breast cancer is a rare type of breast cancer that gets its name from the red appearance of breast's skin. Inflammation is caused by the body's tissue reacting to injury, infection or irritation, and anything that creates this response is called "inflammatory".

Intensity Modulated Radiation Therapy (IMRT)

IMRT is a modern form of radiotherapy. It allows the intensity of a radiation beam to change over a 3D area, meaning that a more even dose of radiation can be given across the breast which accounts for the breast’s shape and size. With standard 2D radiotherapy the intensity can only be controlled in two dimensions so some areas of the breast receive a higher radiation dose, which can cause extra tissue damage and poorer cosmetic outcomes.

Invasive breast cancer

Cancer that has spread beyond the specific area where it first developed into neighbouring healthy tissues.

Involved margin

An area around the tumour site left after surgery that is affected by the cancer and needs further treatment.


Letrozole (Femara)

A type of aromatase inhibitor; a hormone therapy.

Lobular Carcinoma In Situ (LCIS)

LCIS stands for Lobular Carcinoma In Situ. When we talk about breast cancer this usually means tumours that grow into the surrounding breast tissue, called "invasive breast cancer". However, sometimes cancerous changes develop within the lobules or ducts of the breast and do not break out into the surrounding tissue. LCIS refers to "non-invasive" cancerous changes that are contained within the lobules, which are bag-like structures where milk is produced.

Local recurrence

The reappearance of cancer cells after treatment, in the same place the tumour was originally found.


See 'Breast-conserving surgery'.

Lymph nodes (or lymph glands)

These are oval-shaped structures found throughout the body, particularly in the armpit (axilla), neck and groin. They are part of the immune and lymphatic systems where they help the body to fight infection and filter waste materials away from the blood and tissues.

Lymphatic system

The collection of lymph nodes and lymph vessels that carry lymphatic fluid. Together these help filter waste materials from the blood and muscles, and also help the immune system to move to sites of infection.


Long-term swelling in the tissues, which can occur in the arm or upper body after breast cancer surgery or radiotherapy. It is caused by a build-up of excess fluid in the tissue.



A mammogram creates an image of the breast by passing X-rays through the breast tissue at a very low dose. The different ways in which X-rays pass through different types of tissue allows radiologists to see if there is any abnormal tissue in the breast, which could indicate the presence of cancer or non-cancerous changes in the breast such as a benign cyst. In the UK, three-yearly mammograms are offered to women between the ages of 50 and 70 as part of the NHS breast screening programme.


This is a type of surgery in which all of the breast tissue is removed, including the nipple. A modified radical mastectomy also involves removing some of the lymph nodes under the armpit and some muscle from the chest wall.

Metastatic breast cancer

See 'Advanced breast cancer'.


The number of people who die from a disease per year. As is the case with incidence, mortality can be expressed as a number, or a rate, which is the number of people who have died from the disease per 100,000 of a population.


Short for Magnetic Resonance Imaging, this is a method of scanning the body using magnetic and radio waves (not X-rays) to create cross-sectional images. A person is scanned whilst lying on a bed in a cylindrical machine, the machine is noisy and can feel constrictive but taking the images is not painful.

Multidisciplinary team

A team of health professionals with a variety of roles and specialisms, who work together to provide treatment and care.



In breast cancer this usually means a treatment given before surgery to shrink the cancer, possibly meaning surgery is easier and less tissue has to be removed. The most common neo-adjuvant treatment for breast cancer is chemotherapy but targeted therapy and anti-hormone therapy can also be given before surgery.


A reduction in the level of infection-fighting blood cells, called neutrophils.


Oestrogen Receptor

Oestrogen Receptor (or ER for short), is a protein found in many cells around the body, including some cells in the breast. The female hormone oestrogen binds to the ER, which has the knock on effect of switching certain genes on or off, causing a change in the behaviour of the cell; for example, to make the cell grow and make copies of itself.

Around 80 per cent of breast cancers have more oestrogen receptors present in their cells than normal breast cells, and therefore they are particularly sensitive to oestrogen. These breast cancers are called ER-positive or hormone-positive and rely heavily on oestrogen to keep growing. 'Anti-hormone' drugs are used to treat ER-positive breast cancers, and work by either reducing the production of oestrogen (these drugs are known as aromatase inhibitors, and include Femara, Arimidex, Aromasin), or blocking the ER itself (tamoxifen being the most well-known example).


Oncology is the medical term for the study and treatment of cancer and so oncologists are doctors who have trained to be specialists in cancer. They work with a team of specialists to guide patients on which treatments they should receive.

Oncoplastic resection

Surgery involving lumpectomy and cosmetic surgery, sometimes to both breasts, to even their appearance.

Ovarian ablation

Completely blocking the release of hormones by the ovaries, either by surgery, radiotherapy to the ovaries, or treatment with drugs.


Paget’s disease

A rare type of invasive breast cancer that is characterised by skin changes to the nipple.


A doctor specialising in the diagnosis and classification of diseases by laboratory tests, such as examination of tissue and cells under a microscope.

PET scan

Short for positron emission tomography scan, this is when a molecule (called a radiotracer) is injected into the body where it attaches to areas of high activity (such as cancer cells) and gives off a signal that is recorded as a 3-D image. A PET scan can tell doctors about both the structure and function of tissues, and is sometimes combined with a CT scan to collect additional information about the area being investigated.

PhD Grant

Breast Cancer Now's PhD grants are awarded once a year in November. They last for three years, with an average cost of £90,000. A PhD grant funds a young scientist to carry out research under the supervision of an established scientist. The supervisor applies for funding and then recruits a graduate student, and the grant pays for the student's salary and training. These grants help to attract talented young scientists into breast cancer research and encourage sustainability within the scientific research sector.

Find out how to apply for a breast cancer research PhD grant


A specialist in providing physiotherapy, which involves massage and manipulation of the body to promote healing and wellbeing.

Pilot Grant

Breast Cancer Now's pilot grants enable established scientists to explore brand new, innovative ideas in the field of breast cancer research and work out whether a particular line of enquiry is worth pursuing in more depth. Applications for a pilot grant can be made in March and September, there is a maximum of £25,000 awarded for each pilot grant.

Find out about applying for a pilot grant

Positive margin

See 'Involved margin'.


Occurring after an operation.

Primary breast cancer

This is the term for breast cancer that is found in the breast and has not spread beyond the breast or the lymph nodes in the armpit. If breast cancer has spread further, and become secondary breast cancer (also known as metastatic breast cancer), the initial cancer in the breast might be referred to as the “primary” tumour.


A naturally occurring female hormone. It is essential for normal sexual development and the functioning of female reproductive organs.

Project Grant

Breast Cancer Now's projects grants are available to support innovative research into breast cancer. We will award project grants for a clear research proposal that is relevant to breast cancer and is expected to lead to a significant advancement in our understanding of prevention, detection, treatment or the underlying biology of breast cancer. The projects are awarded twice a year in May and November for up to three years, and up to £200,000 can be awarded.

Find out more about applying for a project grant


Quality of life

Quality of life is a term often used by healthcare professionals and researchers to refer to the well-being of patients during and after their breast cancer treatment. Quality of life can be affected by any of the experiences a patient has from diagnosis through to surviving breast cancer, including the physical, psychological and social implications of the disease and its treatment.



A person trained to operate equipment involving radiation, eg for x-rays, mammograms and radiotherapy.


A doctor specialising in the use of x-rays and other imaging methods for diagnosis and treatment.


The use of high energy x-rays to destroy cancer cells.

Receptor tests

Tests of breast cancer tissue conducted in the laboratory to see whether the cancer cells have specific markers (receptors). This helps to determine whether hormone therapy and/or targeted therapy will be effective treatments.


See breast reconstruction.


Recurrence means that a cancer has come back after the original treatment. It is important to remember it is not the same as secondary (metastatic) breast cancer. A local recurrence is when the returning cancer is found in the same breast. A regional recurrence is when the returning cancer is found in the areas close to the breast.


A programme of treatment.


Screening (for breast cancer)

Treatment for breast cancer is most effective when breast cancers are small so early detection is vital. Breast screening is a method of detecting small changes in breast tissue before they can be seen or felt. It involves taking an X-ray image of each breast - a mammogram - which is taken while carefully compressing the breast.

The NHS Breast Screening Programme UK invites women aged between 50 and 70 for free breast screening appointments every three years. This is being extended to women aged 47 to 73 in some areas of England.

Find out more about the signs and symptoms of breast cancer

Secondary breast cancer

When breast cancer spreads from the breast or armpit to other areas of the body, it is called secondary breast cancer. It can also be called metastatic breast cancer and advanced breast cancer.

Sentinel node biopsy

A way of checking to see whether cancer has spread to the lymph nodes in the armpit; sentinel nodes are the first nodes in the armpit to which cancer could spread.

Side effects

Unwanted symptoms caused by medical treatment.


Stage is a measure based on the size of the cancer and whether it has spread to the lymph nodes in the armpit, or further in the body, for example to the liver or bones. Stage is given a number on a scale of 1 to 4 where stage 1 is a breast tumour under 2cm in diameter and there is no cancer found in the lymph nodes, and stage 4 is breast cancer that has spread further in the body, for example to the liver or bones. Stage 4 breast cancer is also known as secondary or metastatic breast cancer.

Find out more about breast cancer staging.

Survival rates for breast cancer (statistics)

As a statistic, survival figures relate to the estimated percentage of women diagnosed with breast cancer who have survived for a certain period after diagnosis; the most commonly used is ‘5-year survival’, which is the percentage of people diagnosed with breast cancer who are still alive five years after their diagnosis. The five year survival rate in the UK is over 80 per cent.

Symptomatic breast cancer

Cancer which is identified because the patient experiences symptoms, rather than through routine screening.

Systemic treatment

Treatment that affects the whole body, such as chemotherapy and hormone therapy.



Also known as Nolvadex, tamoxifen is an anti-hormone therapy used to treat hormone-positive breast cancer, the growth of which is driven by the hormones oestrogen and/or progesterone. It works by blocking the oestrogen receptor (ER) that is overproduced on the cells of most hormone-positive breast cancers, so preventing oestrogen from stimulating the growth of these tumours. It is normally taken on a daily basis for several years.

Targeted therapy

A type of treatment that blocks the growth and spread of cancer by targeting specific molecules in cancer cells. These treatments are designed to specifically attack cancer cells, meaning that they may be less harmful to normal cells and can have fewer side effects than other types of treatment such as chemotherapy.


Group of chemotherapy drugs, eg Taxotere.

Tissue Bank

The Breast Cancer Now Tissue Bank is a unique collaboration with four leading research institutions to create a vital resource of breast cancer tissue for researchers across the UK and Ireland – the UK's first ever national cancer tissue bank. It is an initiative where tissue samples donated by patients from across the UK will be safely and consistently stored. These samples are then made available to scientists to study how and why breast cancer develops and spreads, and to devise the best possible treatments.

TNM (tumour, nodes, metastases) assessment

A method used for staging.


Another name for 'Herceptin'.

Triple assessment

Initial testing for breast cancer, carried out in a breast clinic, which includes physical examination, imaging of the breast and biopsy.

Triple negative breast cancer

Around 15 per cent of breast cancers are found to be ‘triple negative’. This means they lack the three molecules which are used to classify breast cancers; the oestrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2).

This form of breast cancer cannot be treated with targeted drugs commonly used to treat other types of breast cancer, such as tamoxifen and aromatase inhibitors for ER and PR-positive breast cancer, or Herceptin for HER2-positive breast cancer. This leaves triple negative breast cancer patients with fewer treatment options, namely chemotherapy drugs in addition to surgery and/or radiotherapy.

Triple-negative breast cancers (and a related subgroup called ‘basal-like breast cancer’) are more likely to be diagnosed in black women than caucasian women, and they tend to exhibit aggressive behaviour and are more likely to spread. Triple negative breast cancer is also more frequent in people with an inherited BRCA1 mutation.


An abnormal growth or swelling of tissue which may or may not be cancerous.


Ultrasound imaging

Technique for taking pictures of the inside of the body using sound waves.

Uninvolved margin

Area around a removed tumour that contains no cancer cells.


WLE (Wide Local Excision)

See 'Breast-conserving surgery'.