Glossary of medical terms related to cancer

The terms and definitions below, relating to cancer, are provided with the kind consent of Macmillan Cancer Support. They are presented in alphabetical order A-Z.

Use the A-Z tool below to jump to a specific section.


Medical termDefinition
AbdomenThe part of your body with your stomach, bowel and other parts of the digestive system. It is often called your tummy.
Adjuvant therapyThe treatment given after your main cancer treatment. For example, your main treatment may be an operation to remove the cancer. You may then have chemotherapy as an adjuvant therapy to reduce the risk of the cancer coming back.
Advance care planningPlanning ahead for how you want to be cared for.
AlopeciaHair loss. It can happen to the hair on your head, eyebrows, eyelashes, and other areas of the body. Hair loss can be a side effect of some cancer treatments, such as chemotherapy. Your healthcare team will talk to you about how to reduce the chance of this happening. They can also help you get a wig if you want one.
AnaemiaWhen you have a low number of red blood cells in your blood. This can make you feel tired and breathless.
AnaestheticA drug that makes people more comfortable during a medical procedure. A general anaesthetic puts a person to sleep for a while. A local anaesthetic numbs a part of the body so the person cannot feel anything.


Medical TermDefinition
Benign tumourA lump in the body that is not cancer. Benign tumours usually grow slowly and do not spread to other parts of the body.
BiopsyWhen your doctor takes a small sample of tissue from your body and looks at it under a microscope. This is to see if the cells are cancerous or not.
Blood countA routine blood test to measure the number of red blood cells, white blood cells and platelets in your blood. It is also called a full blood count (FBC).


Medical termDefinition
Cancer Care Navigators (CCN)Cancer Care Navigators work alongside Clinical Nurse Specialists to help and support people affected by cancer with their non-clinical needs. These teams are funded jointly by Macmillan Cancer Support and NHS Norfolk and Waveney.
Cancer Nurse Specialist (CNS)Nurses with in-depth knowledge in the specific area of cancer care. They are the main contact during and after cancer treatment.
CarcinogenA substance which can cause cancer, such as radiation or the chemicals in cigarettes.
CarcinomaA type of cancer that starts in epithelial cells. These cells cover the outside of our body and our organs. Most cancers are carcinomas.
Carer’s AssessmentA chance to talk to your local council or social services department about what help you need if you are caring for someone. If you care for someone aged over 18, you have the right to a carer’s assessment and support. For more information, contact your local council in England, Wales and Scotland, or your Health and Social Care Board in Northern Ireland. You can also contact Carers UK.
Central LineA long, hollow tube made from silicone rubber. The line is put into one of the veins in your chest. It can be used to give chemotherapy treatment and other medicines. It can also be used to take samples of your blood for testing. A Hickman® line is a type of central line
Chemotherapythe use of anti-cancer (cytotoxic) drugs to destroy cancer cells, including leukaemia and lymphoma. It can be given alone or with other treatments.
ConsentAgreeing to have treatment. The doctor will usually ask you to sign a form before you have treatment to say that you give your permission. No medical treatment can be given without your consent.
CT Scan(Computerised Tomography Scan) is a scan that uses x-rays to build a three-dimensional picture of the inside of the body. This scan usually takes 10 to 30 minutes and is painless.
CytotoxicMeans toxic to cells. See chemotherapy.


Medical termDefinition
DiagnosisA description of the illness a person has.
DiarrheaHaving frequent or watery bowel movements (poo). It can sometimes be a symptom of cancer or a side effect of some cancer treatments.
DietitianA specialist who can give you advice on healthy eating, especially if you’re having trouble eating and drinking because of your cancer treatment.
DripA way of giving fluids or drugs such as chemotherapy into a vein. It is also called an intravenous (IV) infusion.


Medical termDefinition
FatigueWhen you feel extremely tired most, or all, of the time. Cancer and some of its treatments can cause fatigue.
FertilityThe ability to have children.
Fine Needle AspirationA test that uses a thin needle to take a small sample of cells from your body to be examined.


Medical termDefinition
GradeA way for doctors to describe the growth of a cancer.


Medical termDefinition
HistologyThe study of cells. Doctors look at cells under a microscope to see if they are normal or not. If there are cancer cells, they look to see what type of cancer it is. It is sometimes also called histopathology.
HistopathologistA doctor who examines samples of tissue under a microscope to help diagnose a disease such as cancer.
Hormone TherapyA treatment that can change the amount or action of certain hormones in the body. This can slow or stop cancer cells from growing.
HormonesSubstances produced naturally in the body. They act as chemical messengers and influence the growth and activity of cells.


Medical termDefinition
Immune SystemYour body’s natural defense system. It helps protect against infection and disease. See lymphatic system.
IncontinenceWhen you have trouble controlling your bladder or your bowel.
InoperableWhen cancer cannot be removed by an operation. It might mean cancer has spread to a part of the body where an operation is not possible or too risky.
Intramuscular injection (IM)An injection into a muscle.
Intravenous (IV)When a drug or fluid is given into one of your veins.


Medical termDefinition
LeukaemiaA cancer of the white blood cells. White blood cells fight and prevent infection.
Local TherapyA treatment, for example, radiotherapy and surgery, which only affects a particular area of your body.
LymphA fluid that flows around your lymphatic system.
Lymphatic systemThe system within our body that helps to protect us from infection and disease. It also drains lymph fluid from tissues in the body before returning it to the blood. The lymphatic system is made up of fine tubes called lymphatic vessels. They connect to groups of lymph nodes throughout the body.
LymphoedemaSwelling in a part of the body. It develops because of a build-up of fluid in the body’s tissues. This happens when the lymphatic system, which normally drains the fluid away, is not working properly. It can happen in any part of the body but is most likely to affect an arm or a leg.
LymphomaA cancer of the lymphatic system.
Lymph nodes (lymph glands)Part of the lymphatic system. They are small and bean-shaped. They filter germs (bacteria)  and disease from the lymph fluid.


Medical termDefinition
Malignant tumourA lump in the body that is cancer. Malignant tumours can spread to different parts of the body.
MetastasisWhen the cancer has spread from one part of the body to another. Cancer that has spread is sometimes called a metastatic disease or secondary cancer.
MRI Scan(Magnetic Resonance Imaging Scan) is a scan that uses magnetism to build up a detailed picture of areas of your body.
Multidisciplinary team (MDT)A group of health and social care professionals who work together to manage your treatment and care.


Medical termDefinition
NauseaFeeling sick
Negative result This means that something could not be found. For example, a negative lymph node biopsy means that cancer cells were not found in the lymph nodes.
Neo-adjuvant therapyTreatment given before the main treatment. For example, you might have chemotherapy before surgery to shrink the tumour and make surgery easier or more effective.


Medical termDefinition
Occupational therapistA health professional who can give practical assistance to help you manage everyday activities and increase your independence.
OedemaThe build-up of fluid in the body. It causes swelling.
OncologistA doctor who specialises in cancer care and has advanced knowledge and understanding of cancer treatments. Oncologists treat cancer using methods other than surgery, including chemotherapy and radiotherapy.
OncologyThe medical specialty that deals with cancer.
OrallyWhen you take something by mouth. For example, taking a tablet.
OutpatientWhen you go into hospital for an appointment and leave on the same day. Outpatients do not stay in hospital overnight.


Medical termDefinition
PaediatricsThe medical specialty that deals with children.
Palliative careTreatment that is given to help improve quality of life when the cancer cannot be cured. Palliative treatment aims to meet the physical, spiritual, psychological and social needs of a person with cancer.
PathologyThe study and diagnosis of disease.
PET Scan(Positron Emission Tomography Scan) is a test that measures the activity of cells in different parts of the body. It can be used to find out more about a cancer and see if it has spread to other parts of the body.
PharmacistPrepares and checks the type and dose of medicine that your doctor prescribes. They can also advise you on how to take your medicine and the possible side-effects you may have.
PhysicistAn expert in radiation who will help to plan your radiotherapy treatment.
PhysiotherapistA health professional that specialises in maintaining and improving movement and mobility.
PICC LineA long, thin, flexible tube. It is put into a vein just above the bend in your elbow. It is used to give chemotherapy or other treatments. It usually stays in until treatment finishes.
PlateletA type of cell found in your blood. Platelets help your blood to clot to help stop bleeding. Chemotherapy can reduce the number of platelets in your blood for a time, making you more likely to have bleeding and bruising.
PortacathA long, thin tube that is put in under the skin to give chemotherapy and other drugs. The tube is connected to a small box under the skin.
Positive resultThis means that something has been found. For example, a positive lymph node biopsy means that cancer cells were found in the lymph nodes.
Pre-med(Pre-medication) is a medication that you may be given before a test or treatment. For example, you may have a pre-med before having chemotherapy to help stop you feeling sick.
Primary cancerA cancer that starts in one area of the body. Most cancers are primary cancers.
PrognosisThe likely outcome of a disease. The prognosis gives an idea of how long a person might live.
Progression(or progressed) means that the cancer is still growing, or has continued to spread.
ProsthesisAn artificial body part. A prosthesis is used if that part of the body has been removed. It helps with mobility and appearance.
Psychologist (or counsellor)A health professional who specialises in emotional and behavioural problems; a counsellor is a health professional who also provides emotional support.
PumpSomething that may be used to give you chemotherapy or fluids. The pump makes sure that the right amounts are given over the right amount of time. Some pumps are small and can be taken home so that you do not have to stay in hospital.


Medical termDefinition
RadiographerA diagnostic radiographer uses techniques such as X-ray, MRI and CT scans, to take images. A therapeutic radiographer operates the machine that delivers your radiotherapy treatment.
RadiologistA doctor who specialises in using imaging methods to diagnose medical conditions, including cancer.
RadiologyThe use of imaging such as x-rays and scans to help diagnose cancer.
RadiotherapyUses high-energy x-rays to destroy cancer cells while doing as little harm as possible to normal cells. It can help to shrink and control cancer and relieve symptoms.
RecurrenceWhen cancer has come back. If it comes back to the same area of the body, it is called local recurrence. If it has spread to other parts of the body, it is called distant recurrence.
RemissionWhen treatment is controlling the cancer or has made it temporarily disappear, but it may not have been cured.


Medical termDefinition
Secondary cancers(or secondaries) are where the primary cancer has spread to another part of the body. See metastasis.
StageA way for doctors to describe cancer. It means the extent of cancer. This usually means how big it is and whether it has spread from where it first started.
Subcutaneous injection (SC)An injection given into the layer of fat under your skin.
SurgeonA doctor who specialises in carrying out operations to treat an injury or condition. When treating cancer, different surgeons will specialise in operating on specific parts of the body.
SurgeryAn operation, often to remove something (such as cancer) from the body.
Systemic therapyA treatment that treats the whole body. For example, chemotherapy.


Medical termDefinition
Targeted Therapy(or biological therapy) is a treatment that interferes with cell processes that cause the cancer to grow.
TherapyAnother word for treatment.
TissueThe way your cells line up next to each other to form part of your body. For example, breast cells line up next to each other to make breast tissue.
Treatment CycleThe time between one round of treatment until the next one starts.
TumorA group of cells that are growing in an abnormal way. Tumours can be made up of cells that are not cancerous (benign) or cancerous (malignant).
Tumor markersProteins produced by some types of cancer. They are found in the blood. They can sometimes help doctors to diagnose the cancer, or see how well treatments are working.


Medical termsDefinition
Ultrasound scanA scan that uses sound waves to create a picture of the inside of your body.


Medical termDefinition
X-Ray ScanA way to take pictures of the inside of your body. It can show breaks or problems with your bones and joints. It can also show changes to other body tissues and organs, such as the lungs or breasts.

Further information

For a full list of abbreviations used on this website, take a look at our glossary of terms.