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A to Z of breast cancer

This glossary explains many of the common terms you’ll hear when discussing aspects of metastatic breast cancer, including stages, types, tests, symptoms and treatments. Pick a letter to start.


Advanced breast cancer

Usually refers to metastatic breast cancer, also called Stage IV breast cancer. Breast cancer that has spread locally in the area of the breast, but not to distant organs and tissues, is often referred to as "locally advanced breast cancer," or Stage III breast cancerRead more about breast cancer stages.


A low number of red blood cells. May lead to feelings of tiredness, weakness or breathlessness.

Anti-emetic drugs

Medicines to reduce or prevent nausea.

Anti-hormonal therapy

A treatment to stop or slow the growth of hormone-sensitive tumours. Works by blocking the body’s ability to produce hormones or interfering with hormone action.



Removal of tissue to see if it contains cancer cellsRead more about biopsies.


Also known as bone hardening or bone strengthening treatment. These are drugs to slow or prevent bone damage. They also lower calcium levels.

Blood count

A blood test to show the quantities of each type of blood cell within a sample of blood. Also known as a blood cell count.



Tiny structures that make up all living organisms and the tissues of the body. Cells replace themselves by splitting and forming new cells. 


A treatment that aims to destroy cancer cells using cytotoxic (anti-cancer) drugs. Sometimes shortened to just ‘chemo’.

Clinical trial

Also called a clinical study. A research study testing how well new medical treatments or approaches work on patients. Read more about clinical trials.


Agreeing to something, or giving permission for something to be done.

CT scan

Short for ‘computed tomography scan’. Uses a series of x-rays to create a detailed picture of areas inside the body. You may be given a dye (either to swallow or as an injection) to help the tissues and organs show up more clearly.



Early breast cancer

Breast cancer that has not spread further than the breast or the axillary lymph nodes.



Short for human epidermal growth factor 2. A protein involved in normal cell growth. Some breast cancer cells contain many more HER2 receptors than others. This is called being HER2 positive (HER2+).

Hormone receptors (HR)

A cell protein that binds to a particular hormone. Once the hormone has bound to its receptor, various changes take place in the cell.


Imaging procedures

Also known as imaging tests. These involve making detailed pictures of areas within the body. Examples include CT scans and MRI scans. Read more about scans.



Lab tests

With breast cancer, these tests look for signs of cancer and its progression. Examples include tumour marker tests and blood counts.

Lymph nodes

Small organs in your body which can indicate cancer spread by becoming inflamed or enlarged. They can be an important tool for assessing the stage of your cancer



Tumours that occur when cancer spreads beyond where it started in the body. For example, when breast cancer spreads from the breast to the bone.

Metastatic breast cancer

This is cancer that has spread beyond the breast to another part of the body. It may also be referred to as secondary breast cancer.

MRI scan

Short for ‘magnetic resonance imaging’ scan. Uses radio waves and a powerful magnet to create detailed pictures of organs inside the body.



One of the two female sex hormones along with progesterone. In women, oestrogen levels change over the course of each menstrual cycle.



PET scan

Short for ‘positron emission tomography’ scan. A small amount of radioactive liquid is injected into a vein and a scanner then takes a detailed picture that can be used when looking for abnormalities in the body.


One of the two female sex hormones along with oestrogen. Released by the ovaries during every menstrual cycle to prepare the breasts for milk production and the womb for pregnancy.


When tumours get bigger and/or the cancer spreads within the body. 


In medical terminology this means a plan, such as an agreed process to be followed after someone is diagnosed with metastatic breast cancer. May include a treatment plan and cover the practicalities of treatment



The use of high-energy radio waves to kill cancer cells and shrink tumours.

Randomised trial

Trial involving at least two different groups of participants. The groups are allocated different treatments (which group receives which of the possible treatments is chosen at random). 


When cancer returns after a period of time during which no cancer could be detected. If this happens, it may occur months or years after the initial treatment. Cancer may recur where it first appeared or elsewhere in the body.


When cancer returns after a period of improvement.


When tumours shrink (partial remission), in some cases to the extent that they can no longer be detected by tests and scans (complete remission).


Secondary breast cancer

Another name for metastatic breast cancer.

Stage III

Cancer that has spread beyond the breast and lymph nodes immediately around it, but has not reached distant organs. Can also be called locally advanced breast cancer. 

Stage IV

The most advanced stage of breast cancer – when it has become metastatic. 


The stages of cancer (I-IV or 1-4) are used to explain how far the cancer has spread in your body. Read more about breast cancer stages.



Targeted therapy

A treatment targeting specific characteristics of cancer cells to prevent them from growing and dividing.

TNM classification

Another classification system used by doctors to explain how far the cancer has spread in your body in order to determine your overall stage.

  • T stages (tumour) – the size of the tumour in the breast
  • N stages (nodes) – the extent to which the cancer has spread to the lymph nodes near the breast
  • M stages (metastases) – the extent to which the cancer has spread outside of the breast to other parts of the body such as the bone, liver, and lungs

Your doctor puts the TNM results together to give you your overall stage. This is usually what the doctor writes on your test forms.



A scan which uses high frequency sound waves to build up a picture of the inside of the body.



Radiation used for taking pictures or radiotherapy. A mammogram uses a x-rays.