Glossary of breast cancer terminology

Posted by Emma Herring on 12 April 2022


We know that when you’re newly diagnosed with breast cancer, you come across lots of terminology which can be overwhelming. Our simple glossary is designed to help you navigate your way through all this information and provide links to resources where you can get further details. We’ve tried to include some of the most common terminology and organised it in sections from diagnosis through to after treatment. We’ve put this together from our own research and with help from the Future Dreams Breast Care Nurse and other medical professionals listed at the foot of this article.


Adjuvant Treatments This is additional cancer treatment given after primary treatment, such as surgery, to lower the risk of the cancer coming back. It may include chemotherapy, radiation therapy, hormone therapy or targeted therapy.

BRCA 1 and BRCA2 Genes that encode proteins that are involved in DNA repair and help maintain genetic stability. Mutations in these genes increase the likelihood of developing breast cancer earlier; the likelihood of developing a second breast cancer and of a poorer diagnosis. Tests can be carried out to detect the presence of these mutations and are typically carried out in women from families with a history of breast cancer.

Breast Density Breasts are made of fat and glands (that make milk), held together by fibrous tissue. The more glands and fibrous tissue present, the “denser” the breast. Breast density has nothing to do with the way breasts look or feel. Dense breasts are normal and common but make it harder for radiologists to see cancer on a mammogram. Dense breasts increase both the risk of a cancer being missed on a mammogram and, also, of developing breast cancer. For more information visit:

Core Biopsy A sample of tissue taken for investigation, usually done in the radiology room under local anaesthetic

Clinical Trials These aim to establish better ways to reduce risk, diagnose or treat cancer, or manage patient symptoms. Most advances in cancer treatment in recent years have come out of a clinical study. Without trials, new therapies could not be approved, so clinical trials are essential for advancing medical progress. See our Clinical Trials support pages for more information.

Cluster Calcifications Clusters of calcium that develop in the breast that are painless and found on routine mammograms and are usually harmless. Certain patterns, such as tight clusters can indicate pre-cancerous changes to breast tissue. See the Macmillan website for further information.

CT Scan Often referred to as CAT scans, computerised tomography (CT) scans use X-rays to build up detailed images of the inside of the body. They are carried out by radiographers. See the Cancer Research UK website for more information.

De Novo In breast cancer, de novo means that the breast cancer was diagnosed when it had already spread to other parts of the body. It is described as metastatic breast cancer.

Ductal Carcinoma in Situ (DCIS)/Non-invasive Breast Cancer The earliest form of breast cancer where the cancer cells are completely contained in the ducts and lobules of the breast and the cells haven’t broken through or grown into surrounding breast tissue. This is often picked up by routine mammogram and rarely shows up as a lump.

Ductal Invasive Breast Cancer This is the most common type of breast cancer where the cancer originated from the milk ducts in the breast. It is often called breast cancer of ‘no special type’ or ‘not otherwise specified’ as the breast cells when examined under a microscope have no specific features.

ER & PR Receptors Around 70-80% of breast cancers have high levels of receptor for the naturally occurring hormones oestrogen (ER) and progesterone (PR) on their tumour cells. This means that the tumour is dependent on these hormones for growth and as a result, anti-hormone medication can be used as part of their cancer treatment. There is more information on the Cancer Research UK website.

Fine Needle Aspiration A procedure in which smaller samples of tissue are taken using a needle and syringe.

Genetic Testing Certain breast cancers and the presence of a strong family history of breast cancer and other cancer types may mean that genetic testing is something the medical team may consider. This is usually done at a specialist centre. See our pages on genetic testing for more information.

Grade and Stage Grading is how abnormal the cancer looks under a microscope while staging considers how big the cancer is and whether it has spread. The stage and grade of cancer is used by doctors to help them decide your treatment plan. See the Cancer Research UK website for more information about types of grading and the stages of cancer.

Her2 Receptor Some 15-20% of breast cancers have a higher number of HER2 receptors on tumour cells, which are involved in cell growth and multiplication. These HER2-positive cancers tend to be more aggressive than HER2-negative ones. There are targeted treatments available that block HER2 receptors in these cancers. There is more information on the Macmillan Cancer Support website.

Inflammatory Breast Cancer This is a rare type of breast cancer and unlike other types you may not feel a lump. Inflammatory breast cancer cells grow along lymph vessels in the skin of the breast and block the vessels. The breast becomes inflamed and swollen.

Invasive Breast Cancer When breast cancer cells have grown outside their origin (milk ducts or lobules) into the surrounding tissue within the breast. Invasive breast cancer has the potential to spread around the body.

Invasive Lobular Breast Cancer When cancer cells originate in the lobules of the breast. Sometimes it doesn’t appear as a rounded lump and can be quite subtle.

Lymph Vascular Invasion Breasts contain blood vessels and other tiny tubes called lymph vessels. If breast cancer cells spread into these vessels, it’s called lympho-vascular invasion. This may increase the chances of the breast cancer spreading to somewhere else in the body.

Mammogram An X-ray that looks at the whole of the breast usually from two angles. Mammograms can detect cancers that can be felt – usually as a lump – and those that can’t.

MRI Scan Magnetic Resonance Imaging (MRI) is a type of scan that using magnetism and radio waves to create pictures. They produce pictures from angles all around the body and shows up soft tissues very clearly and can take between 15 and 90 minutes. See the Cancer Research UK website for more information.

Neoadjuvant Treatment This is treatment, such as chemotherapy, given as a first step to help shrink a tumour before the main treatment, usually surgery, is given.

Occult Breast Cancer This is a type of breast cancer where the primary tumour cannot be identified in the breast with a mammogram, ultrasound or MRI, but cancer is found in the axillary (armpit) lymph nodes (glands).

Oncotype DX Test Some breast cancers do not require chemotherapy. This is a test your oncologist may carry out to see whether you could benefit from chemotherapy.

PET Scan Positron emission tomography (PET) scans produce three-dimensional images of inside the body. They are useful in confirmed cases of cancer to determine how far the cancer has spread and how it is responding to treatment. More information is available on the Cancer Research UK website.

Primary Breast Cancer Breast cancer that has not spread beyond the breast or lymph nodes (glands) under the arm.

Prognosis This is an estimate of the likely course and the outcome of a cancer diagnosis. It is often viewed as the chance that the disease will be treated successfully.

Stereo Core Biopsy A biopsy carried out under the guidance of the mammogram machine.

Triple Negative Around 10-15% of breast cancers are triple-negative which means they have neither high levels of hormone receptors nor of HER2 receptors. Treatment usually includes surgery and chemotherapy.

Ultrasound scan A procedure used if there is a lump that can be felt, or an abnormality seen on a mammogram or MRI


Axillary Node Clearance An operation to remove all the lymph nodes from the armpit (axilla).

Breast Reconstruction This is the reconstruction of a breast shape using surgery and can be done if you have been recommended to have a mastectomy. There are many different options, including breast implants and using tissue from another part of your body. Your surgeon will discuss the options with you. For information on the types of reconstruction see the pages on the Macmillan Cancer Support website.

Cording Cording can happen after surgery to remove the lymph nodes in your armpit when you can develop a cord-like structure under the skin either around your armpit or on your upper arm. It is important that you do the exercises you are given so that you regain full movement in your arm and do not get a frozen shoulder. See our section on Taking Out Lymph Nodes for further information and helpful advice.

Drain A thin plastic tube placed in one end in the surgical area and the other comes out through the skin and connects to a small plastic bottle. Drains are used after surgery, particularly after a mastectomy and axillary nodal clearance, to remove any fluid that may accumulate.

Lumpectomy, WLE (wide local excision) The removal of a breast cancer lump. It is also known as a wide local excision. An image guided wide local excision removes the lump with the help of technologies that localises the cancer. There is more information on the Cancer Research UK website.

Lymphatic System Made up of thin tubes (lymph vessels) and lymph nodes, the lymphatic system runs throughout the body and plays a key role in our immune system. It helps to fight bacteria and other infections and destroys old or abnormal cells like cancer cells.

Mastectomy, Skin Sparing, Nipple Preserving A mastectomy is the removal of the entire breast, including the nipple-areola and the skin. The result is a flat chest. A skin sparing mastectomy means the majority of the skin overlaying the breast is preserved and this is usually the method for breast reconstruction. A nipple-preserving mastectomy leaves the nipple intact, as well as the areola and the skin.

Oncoplastic surgeon A breast cancer surgeon specially trained to carry out certain types of breast reconstruction.

Pathology report Following a biopsy or breast cancer surgery, tissue will be removed and looked at under a microscope by a pathologist. Further tests may be carried out to provide more information and the results in a pathology report provide details about the breast cancer and help to set out your treatment plan.

Sentinel lymph node biopsy The removal of the closest draining lymph nodes in the armpit (axilla) that would be affected should the cancer start to spread. Sentinel means guard.


Blood Count Blood tests carried out before each chemotherapy cycle to check the levels of a range of things including red blood cells, platelets and neutrophils (white blood cells).

Cannula A thin tube fitted into your hand or arm each time you have chemotherapy treatment through which the drugs are administered.

Cardiotoxicity When the heart muscles are weakened, and the heart is not as efficient at pumping blood. This can be a side effect of certain chemotherapy drugs or targeted therapies and you may have regular scans of your heart to check for damage. See echo cardiogram in our ‘During Treatment generally’ section of this glossary.

Central Line/Hickman Line A long, thin hollow tube inserted into a vein in your chest to give chemotherapy or other drugs. See the Macmillan website for more information.

Chemotherapy A treatment that uses drugs, either through the vein or in tablet form to target any cancer cells that may be circulating.

Chemotherapy Drugs Please see the Cancer Research UK website, Breast Cancer Now or Owise for a list of chemotherapy drugs.

Cold Cap This tries to help preserve hair. Scalp Cooling Technology can alleviate the damage caused to the hair follicles by chemotherapy by reducing the temperature of the scalp by a few degrees before, during and after chemotherapy treatment. See our page on hair loss for more details.

Cycle The period of time between one round of treatment and the next. See our page on chemotherapy for more information.

Intravenous Administrating drugs or treatment through the veins.

Neutropenia When your while blood cell count (neutrophils) falls below a certain level during chemotherapy treatment. Your hospital will give you information about what to look out for and what you should do if this should happen.

Neutrophils White blood cells which fight infection

Picc Line Used to administer chemotherapy drugs, it is a long, thin hollow tube inserted into one of the large veins in the arm above the elbow. See the Macmillan website for more details.

Portocath/Implantable Port A means of administering chemotherapy or other drugs, it is usually inserted under the skin on the chest. See the Macmillan website for more information.

Pre-meds and Post-meds Drugs that are given before and after chemotherapy to helps deal with side effects. These can include anti sickness drugs, steroids and antihistamines.


External beam radiation therapy Externally delivered radiation therapy delivered at a distance from the body.

Fractionation/Fractions External beam radiotherapy (radiation therapy) is normally given in small parts daily, a maximum of five days a week with the same amount of radiation dose every day. The separate parts of the treatment are called fractions. Depending on what treatment you are having you could have as many as 35 fractions – please discuss with your medical team.

Linear accelerator or LINAC The most common type of machine used to deliver external radiotherapy (radiation therapy) treatment.

Planning appointment This happens a few weeks before your treatment starts. Here, you will have a CT scan in the same position you need to be in for your radiotherapy treatment. It is important to let the pre-treatment therapeutic radiographers know if you find anything uncomfortable as it is difficult to make adjustments once the treatment starts. They will then take lots of measurements and give you semi-permanent pinpoint tattoos where needed. The treatment therapeutic radiographers use these tattoos to help get you in the same position when you go for your radiotherapy (radiation therapy) treatments.

Radiotherapy (radiation therapy) A treatment where radiation is directed with millimetre accuracy towards cancer cells in the body with the intention of killing them. It is a highly accurate, targeted, and safe treatment. Normal healthy tissue is avoided where possible using innovative treatment methods.

Treatment Plan Each person’s treatment is individually planned by an oncologist, consultant therapeutic radiographer, dosimetrist and a physicist. This can take a few weeks to plan safely using your CT scan results and any other previous scans you’ve had to ensure the radiation is directed at the treatment area and avoids as much healthy tissue as possible.

Biological therapy/immunotherapy

CDK4/6 inhibitors These are targeted cancer drugs and include Abemaciclib, Palbociclib and Ribociclib. More information is on the Cancer Research UK website for each of these.

Herceptin/Trastuzumab Herceptin is the brand name of a drug called Trastuzumab and is a biological therapy and will usually be given to you if your breast cancer is HER2+ve. It targets HER2+ve receptors on the cancer cells and destroys them. Depending on your treatment plan and hospital, you will be given the drug every three weeks over a certain period of time. It is either given by IV or subcutaneous injection. See our section on Her2+ve breast cancer for more details.

Pembrolizimab is a type of immunotherapy which helps use your immune system to kill cancer cells. See the Cancer Research UK website for more information.

Endocrine/hormone therapy

Aromatase Inhibitors Drugs that are used to treat breast cancer in women who have been through the menopause. See our Hormonal Therapies section for more details. They include: Anastrozole, Exemestane and Letrozole.

ER (oestrogen)/PR (progesterone) Status Some cells have receptors that bind to these hormones and reply on them to grow. Breast cancer cells with oestrogen receptors are ER positive, while those with progesterone receptors are PR positive. If neither receptor is expressed, then the cancer is ER/PR negative. See our Hormone Receptor Positive page for more information.

Fulvestrant/Faslodex A type of hormone therapy. See the Breast Cancer Now website for more information.

Hormone receptor Breast cancer cells can have hormonal receptors and tests are carried out when you are diagnosed to check whether certain hormones that are present in your body stimulate your breast cancer cells to grow. See our Hormone receptor positive page for more information.

Tamoxifen A hormone therapy drug. See the Breast Cancer Now website for further details.

Zoladex A type of hormone therapy. Pre-menopausal women may be offered an injection called Zoladex which is given in the stomach area every 28 days to stop their ovaries from producing oestrogen which will effectively give them a medical menopause. For more information see the Cancer Research UK website.

During treatment generally

Cellulitis An infection of the skin and the soft tissues underneath. The skin can be painful, hot and swollen.

Dexa Scan/Bone Density Scan A scan that uses low dose x-rays to see the density or strength of your bones.

Echocardiogram (echo) A test using ultrasound to check and monitor the condition of your heart.

Oncologist Doctors who treat and manage patients with cancer. You will see an oncologist if you are going through radiotherapy, chemotherapy, or other forms of cancer treatment.

Osteopenia and Osteoporosis Osteopenia is when your bone density is lower than is usual for your age. Osteoporosis is serious case of bone loss that makes you more susceptible to fractures.

Social Prescribing is a way of connecting people to activities, groups, and services in their community to meet the practical, social and emotional needs that affect their health and wellbeing. To find out more visit this NHS England website.

Steroids Steroids are drugs often given as part of treatment for cancer, or to help with the side effects of treatment. See the Macmillan website for more information.

Subcutaneous Injection An injection into the fatty tissues under the skin.

Secondary breast cancer

Bone Metastases or Mets When cancer cells spread from the breast to the bones. See our secondary breast cancer pages for more information and support resources.

Brain Metastases or Mets These occur when cancer cells spread from the breast to the brain. See our support pages on secondary breast cancer for further information and support resources.

Palliative care Medical care that helps relieve pain, symptoms or stress caused by serious illness.

Secondary/Metastatic/Advanced/Stage 4 When the cancer has travelled beyond the breast to other parts of the body, including the liver, lung and bones. It is treatable but not curable. See our support pages about secondary breast cancer for more information.

After treatment

Bisphosphonates Drugs, used in women who have been through the menopause, to reduce the risk of primary breast cancer spreading to the bones. They are also used in secondary breast cancer treatment when there is bone involvement to help strengthen the bones. See the Breast Cancer Now website for more information.

Lymphoedema An accumulation of lymph fluid causing swelling. It usually affects the forearm, hands and fingers, but it can also affect the breast. See our Lymphoedema Q&A for more information.

Recurrence, Local Regional Disease If the cancer returns in the breast (after a lumpectomy) or in the chest wall (after a mastectomy) it is known as a local recurrence. If it returns to nearby lymph glands it is called a regional recurrence.

Remission/NED/NEAD Remission, no evidence of disease or of active disease is a term used by doctors when tests and scans show there are no signs or symptoms of your cancer after treatment.

Seroma Fluid that accumulates under the skin, usually around the surgery site. It is very common, especially after a mastectomy and axillary nodal clearance.

Further information

We’re really grateful to everyone who has helped us to put this glossary together, in particular Naman Julka-Anderson, Senior Therapeutic Radiographer (Macmillan Treatment Review Radiographer) and Radiotherapy UK charity ambassador who reviewed the radiotherapy section, and to Dr Tasha Gandamihardja, Consultant Oncoplastic Surgeon for her glossary of terms on which this is based, and for doing a full review of this glossary. She has a brilliant YouTube site with lots of useful information which is well worth checking out.

For a more detailed glossary, and one which covers things like the different chemotherapy drugs and the more unusual terminology used by medical staff, we refer you to the fabulous Owise glossary. Owise is an accredited mobile app and website that helps you to regain control of your life from the first day of a breast cancer diagnosis. Using the app, you can monitor and share changes of your day-to-day well being with your care team and trusted individuals, record upcoming appointments, make notes at appointments, maintain contact details and treatment plan details, and have access to a large range of helpful information and advice.

Future Dreams hold a range of support groups, classes, workshops and events to help you and your carers during your breast cancer diagnosis. These are held both online and in person at the London-based Future Dreams House. To see what’s on offer and to book your place, see here.

To return to the homepage of our Information Hub, click here where you can access more helpful information, practical advice, personal stories and more.

March 2024

Unless otherwise specified, the information and content provided on this page has been written from a patient’s perspective then reviewed by a breast care nurse and it is intended for information and educational purposes only. It is not intended to substitute for professional medical advice. Please contact your medical team for advice on anything covered in this article and/or in relation to your personal situation. The links and/or recommendations in this article to third-party resources are for your information and we take no responsibility for the content contained in those third-party resources.


Sylvie Henry and Danielle Leslie founders of Future Dreams breast cancer support
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Sylvie and Danielle began Future Dreams with just £100 in 2008. They believed nobody should face breast cancer alone.  Their legacy lives on in Future Dreams House.  We couldn’t continue to fund support services for those touched by breast cancer, raise awareness of breast cancer and promote early diagnosis and advance research into secondary breast cancer without your help. Please consider partnering with us or making a donation.

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