We know there is a lot of medical terminology surrounding secondary (metastatic) breast cancer and these terms can be difficult to navigate. Here is a glossary of some of the most commonly used terms.

On this page you will find: 

Glossary of Medical Terminology


Ablation: A treatment that destroys tumours using heat, cold, or other methods, often without surgery.

Abraxane: A chemotherapy drug, also known as Nab-Paclitaxel used to treat breast cancer. 

ADCs (Antibody Drug Conjugates): Medicines that use antibodies to precisely target and attack cancer cells whilst reducing harm to healthy cells.

Adjuvant Therapy: Extra treatment given after the main cancer treatment to reduce the chances of cancer coming back. For example, the main treatment could be an operation to remove the cancer and then a patient might have chemotherapy as an adjuvant therapy to reduce the risk of the cancer coming back.  

Advanced Breast Cancer: Cancer that has spread from the breast to other parts of the body.

Alopecia: Loss of hair from the head or body. 

Alternative Medicine: Although there is no universally agreed definition of alternative medicines, typically these are treatments that fall outside of mainstream healthcare with examples including herbal supplements, homeopathy and acupuncture.

Anaemia: When the body doesn’t have enough red blood cells. Symptoms of anaemia include feeling tired and weak.

Ascites: Buildup of fluid in the belly.


Benign tumour: Used to describe non-cancerous lumps in the body. Benign tumours usually grow slowly and do not spread to other body parts.

Biological Markers: Molecules in the body that doctors measure to learn important details about cancer to guide treatment decisions. Also known as biomarkers and include genes, proteins, hormones, or other substances.

Biological Therapy: Treatments that boost the ability of the immune system to kill cancer cells. Also known as Immunotherapy.  

Biopsy: Removal of a small sample of tissue from the body to investigate if the cells are cancerous or not. 

Blood Count: Sometimes known as a full blood count (FBC). A routine blood test that measures white blood cells, red blood cells and platelet levels in the blood. 

Bone Metastases: Cancer that has spread to the bones, which might cause pain or other issues.

Breast biopsy: A procedure to take a small sample of breast tissue to check for cancer cells.

Breast-conserving surgery: Surgery that removes the cancer but keeps as much breast tissue as possible.

Breast Density: The number of different tissues in the breast, which can be seen on a mammogram.


Carcinoma: A type of cancer originating in epithelial tissues, which are tissues that cover the outside of our body and organs. Most cancers are carcinomas.

CDK Inhibitors: A class of medications that slow down the growth of cancer cells by blocking certain proteins that help cancer grow.

Cellulitis: A skin infection usually caused by bacteria that causes redness, swelling, and pain.

Chemotherapy: Chemical drug treatment to stop or slow down the growth of cancer cells.

CNS (Central Nervous System) Metastases: Cancer that has spread to the brain or spinal cord.

Cognitive impairment: Difficulty concentrating or being more forgetful as a result of a cancer diagnosis or treatment. Sometimes called ‘chemo brain’ or ‘chemo fog’.

Complementary Therapy: Also known as alternative medicine, see above. 

CyberKnife: A specialised radiation therapy that uses a robotic arm to precisely deliver radiation to tumours in different parts of the body, offering high doses of radiation with extreme accuracy over a few sessions.


ECHO (echocardiogram): A type of ultrasound of the heart, to check how well it is working.

Embolism: When blood flow is blocked, usually by a blood clot or air bubble.

Endocrine Therapy: Treatment that changes the body's hormone levels to slow or stop the growth of cancer cells.

ER Status (Oestrogen Receptor Status): The Estrogen Receptor (ER) is a type of receptor that can be present on breast cancer cells. If the ER is found to be expressed by breast cancer cells, the breast cancer will be termed ER positive (ER+). If the breast cancer doesn’t express the ER it will be termed ER negative (ER-). If the cancer is ER+ it means oestrogen might help it grow, guiding doctors to consider treatments that block the effect of oestrogen on cancer cells.


Gamma Knife®: Radiation therapy often used to target brain tumours or blood vessel lesions in the brain. Gamma radiation beams are focused on the tumour or lesion location so that healthy brain tissue is less impacted.


HER2 (Human Epidermal Growth Factor receptor 2): A receptor that is found on the surface of normal breast cells. However, in some breast cancers HER2 is found in an abnormally high amount and contributes to the growth of breast cancer. If HER2 is found in substantial amounts in breast cancer cells the cancer will be referred to as HER2 positive (HER2+) and if HER2 is lacking in breast cancer cells the cancer will be referred to as HER2 negative (HER2-). The HER2 status of breast cancer will determine if treatments that target HER2 will be suitable or not.

Hyperplasia: An increase in the number and growth of cells.


Immunosuppression: Reduced ability of the immune system to protect against infection and disease. Can be caused by chemotherapy.

Immunotherapy: Treatments that boost the ability of the immune system to kill cancer cells. Sometimes known as Biological Therapy. 

Intramuscular (IM): Injected into a muscle.

Intravenous (IV): Injected into a vein.


Lymph Fluid: Fluid that flows around the lymphatic system.

Lymph Nodes: Small structures that are part of the immune system that aid in fighting infections by filtering bacteria from lymph fluid. Lymph nodes are typically checked for cancer spread.

Lymphatic System: The lymphatic system helps protect us from infection and disease and is made up of fine vessels called lymphatic vessels. Lymphatic vessels connect to groups of lymph nodes throughout the body.  

Lymphoedema: Swelling in arms or legs caused by fluid buildup sometimes due to cancer treatment.


Malignant Tumour: Cancerous tumours capable of invading and spreading to other areas.

Mammogram: A special X-ray of the breast to look for signs of cancer.

Metastatic Breast Cancer: Breast cancer that has spread beyond the breast to other body parts.

Metastatic Progression: When cancer spreads from where it started to other parts of the body.

Mastectomy: Surgery to remove the entire breast.

MRI: Magnetic Resonance Imaging Scan. A scan that utilises magnetism to build up a detailed picture of the body.


NEAD (No Evidence of Active Disease): Signifies no detectable cancer activity after treatment, indicating a positive response.

Neoadjuvant: Treatment administered before the main treatment, often to shrink tumours. For example, you might be given chemotherapy before surgery to reduce tumour size to make the surgery more effective.

Neutropenia: When your body doesn’t have enough of a specific type of white blood cell, which can raise the risk of infections.


Palliative Care: Special care to help improve life quality for people with serious illnesses, focused on relieving symptoms and stress.

PET Scan: Positron Emission Tomography. A scan that measures the activity of cells in the body and can be used to see if cancer has spread. 

PICC Line: A thin, long flexible tube inserted into a vein in the arm to administer chemotherapy or other treatments. A PICC line usually remains in place until treatment finishes. 

Prognosis: The likely outcome of a disease, including the chances of getting better and how the illness might progress.

Prosthesis: An artificial body part, such as a breast implant which is used to restore shape when all or part of the breast has been removed.


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

Reconstruction: Surgery that rebuilds the breast shape after all or part of the breast has been removed.

Recurrence: When cancer comes back. Local recurrence means the cancer has returned to the same area of the body. Distant recurrence means it has spread to other parts of the body. 

Remission: When treatment is controlling the cancer or has made it disappear temporarily, but the cancer may not have been cured.  


Seroma: A collection of fluid that forms under a wound after an operation. It is common after breast surgery and can cause discomfort. 

Spinal cord compression: Pressure on the spinal cord and nerves. It can be caused by the cancer growing in, or spreading into, the bones of the spine and can result in permanent damage to the spinal cord.

Stage: The stage of a cancer is used to describe the size of a tumour and how far it has spread from where it originated. Stage 4 cancer means the same as metastatic cancer and means the cancer has spread to at least one other body organ. 

Subcutaneous injection: An injection into the layer of fat under the skin.  

Systemic Therapy: Treatment that works all over the body. Chemotherapy is an example of systemic therapy. 


Tamoxifen: A hormone therapy drug used to treat breast cancer.

Targeted Therapy: Treatment that focuses on specific features of cancer cells, often causing fewer side effects than chemotherapy.

Triple Negative Breast Cancer (TNBC): a term used to describe breast cancer that does not have any of the three receptors (ER, PR & HER2) that are commonly found in breast cancers that are typically used to classify breast cancer. TNBC accounts for ~15% of all breast cancer cases and around 8,000 women are diagnosed with TNBC in the UK each year.


Visceral Metastases: The spread of cancer to organs like the lungs, liver, or brain.


Wide local excision (WLE): Surgery that removes the cancer along with some healthy tissue while keeping as much of the healthy tissue as possible.

Wire localization: Using a thin wire to guide the surgeon to the area of concern found on scans during surgery.


X-ray: A form of radiation that can be used at low levels to make an image of the body or at high levels to kill cancer cells.

Glossary of Medical Professionals

Allied Health Professionals: A term used to describe a wide range of specialists who provide different types of care and support during and after cancer treatment, but are not doctors or nurses. These include dietitians, occupational therapists, physiotherapists and counsellors and they could be based in the community or Hospital.

Clinical Nurse Specialist
: A registered nurse with advanced training and expertise in a specific area (like oncology), providing specialised care and support to patients and families.

Consultant: A senior doctor who provides expert advice and guidance, often overseeing a team of healthcare professionals.

Dietitian/Nutritionist: An expert who provides advice on healthy eating during cancer treatment, helping manage side effects and maintain good nutrition.

GP: A General Practitioner or Family Doctor is responsible for all aspects of health care at home and will work closely with other members of a healthcare team that support a patient. GPs can arrange referrals to specialists and help with symptoms and side effects both during and after treatment.

Occupational Therapist: Helps patients maintain or regain independence in daily life activities during and after cancer treatment.

Oncologist: A doctor specialising in diagnosing and treating cancer, overseeing the overall cancer care and treatment plan of a patient.

Palliative Care Specialist: A healthcare professional who focuses on improving the quality of life for patients facing serious illnesses, providing comfort care and symptom management.

Pathologist: A doctor who examines tissues, blood, and other body fluids to diagnose diseases like cancer and determine its characteristics.

Pharmacist: Expert in medications, advising on proper usage, managing side effects, and ensuring patients understand their prescriptions.

Physical Therapist: A specialist who helps patients regain strength, mobility, and manage pain through exercises and therapies.

Psychologist/Psychiatrist: Mental health professionals who help patients cope with emotional challenges, anxiety, and stress related to their cancer diagnosis and treatment.

Radiologist: A doctor who interprets medical imaging tests (like X-rays, MRIs, and CT scans) to diagnose and monitor diseases, including cancer.

Research Nurse: A nurse involved in clinical research studies, helping to conduct trials, gather data, and ensure patient safety and care during research participation.

Social Worker: Offers support and resources to patients and families, addressing emotional, financial, and practical challenges during cancer treatment.

Surgeon: A doctor specialised in performing surgeries, including operations to remove tumours or perform biopsies.

Written by Linc Yuan, University of Edinburgh

Reviewed by Senior Research Nurse Catherine Graham, Raigmore Hospital, Inverness

Date of last update: January 2024