Cancer words for kids

When talking to children about cancer, try to give them explanations they can understand. This may mean finding creative ways to explain cancer, but it’s also important to introduce the correct cancer terms early on as these are words they are likely to hear.

The following list of cancer terms provides two versions of each definition, one for younger children and one for older children. You can also go to our general glossary for any cancer terms that aren’t listed here.

Key to symbols

For younger children: 
For older children and teenagers: ⇑ 

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A – G words


A medicine that makes someone go to sleep so they don’t feel anything when they have an operation.
A drug that stops people feeling pain during a procedure such as surgery. A general anaesthetic puts someone to sleep. A local anaesthetic just numbs one area of the body.


A bump or lump on the body that isn’t dangerous.
Cells that are not cancerous (malignant).

When the doctor looks at cells in the body to see if they’re healthy or not.
A test to diagnose cancer. The doctor takes small bits of tissue from the body and looks at them under a microscope to see if the cells have changed.

blood count
A test that checks how healthy the blood is.
A test that counts the different types of blood cells in the body.


Cancer is a disease that happens when bad cells stop the good cells from doing their job. These bad cells can grow into a lump and can spread to other parts of the body.
Cancer is the name for more than 200 diseases in which abnormal cells grow and rapidly divide. These cells usually develop into a lump called a tumour. Cancer can spread to other parts of the body.


The body is made up of billions of tiny things called cells, and each has a job to make your body work and stay healthy.
Cells are the building blocks of the body. Our bodies constantly make new cells to help us grow, to replace worn-out cells, or to heal damaged cells after an injury.

Special medicine that kills the bad cancer cells.
Special drugs that kill cancer cells or slow their growth.

child life therapist
Someone who helps kids understand what is going on and how to have fun when they are in hospital.
A health professional who helps children manage the stress and anxiety of being in hospital through play and other coping strategies.

CT scan
A test that makes pictures so doctors can see what’s happening inside the body.
A procedure that takes x-rays to get 3D pictures of the inside of the body. The pictures show if cancer is present.


When the doctor works out what is making someone sick.
Working out what kind of disease someone has.


Someone who helps people work out the healthiest food to eat.
A health professional who supports and educates patients about nutrition and diet.

A person who gives someone else blood or another part of their body.
The person who gives blood, tissue or an organ to another person for a transplant.

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H – L words


A doctor who treats people whose blood makes them sick.
A specialist doctor who treats people with blood disorders.

hormone therapy
A treatment that helps stop cancer cells growing.
A treatment that blocks the body’s natural hormones, which sometimes help cancer cells grow. It is used when the cancer is growing in response to hormones.


immune system
The part of the body that helps someone stay well by getting rid of germs inside the body. It fights illness if somebody does get sick.
A network of cells and organs that helps protect the body from germs like bacteria and viruses, which can make people sick.

When someone gets sick very easily.
Weakening of the immune system, often caused by disease or treatment.

A treatment that helps the body fight cancer.
The prevention or treatment of disease using substances that change the immune system’s response. Also called biological therapy.

Putting a needle into a vein (where blood flows in the body).
Putting something into a vein, like a drip for feeding, or a needle to give medication or take out some blood.


lymph nodes
Lymph nodes are like filters that remove germs that could harm you. Sometimes, the germs can make some of the lymph nodes swell.
Small, bean-shaped structures that form part of the lymphatic system and help fight infection.

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M – P words


maintenance treatment
When someone is given medicine for a long time to help keep the cancer away.
Treatment given for months or years as part of the treatment plan. Often used for acute lymphoblastic leukaemia.


Another way of saying cancer. Cells or lumps that are bad. 
Cancer. Cells that are malignant can spread to other parts of the body.

medical oncologist

A special doctor who uses strong medicine to treat people with cancer.
A specialist doctor who treats cancer with chemotherapy.

metastasis (advanced cancer)

When the bad cells have travelled to another part of the body.
When cancer has spread from one part of the body to another. Also known as secondary cancer.

A special way of taking pictures of the inside of a person’s body. MRI stands for ‘magnetic resonance imaging’.
A magnetic resonance imaging scan. A scan that uses magnetism and radio waves to take detailed cross-section pictures of the body.


Feeling sick in the tummy.
Feeling as if you’re going to vomit. Nausea is a common side effect of chemotherapy.


occupational therapist
Someone who helps people work out how to do things for themselves again after they have been sick.
A health professional who helps people solve physical and practical problems after illness to they can lead independent lives.


palliative treatment
Sometimes the doctors and nurses can’t stop the cancer from growing, and they will give someone medicine to make them feel better and get rid of any pain.
Treatment that reduces or stops symptoms but doesn’t try to cure the cancer.


A special way of taking pictures of the inside of a person’s body. The person is given an injection with a special liquid that shows up in the pictures and helps the doctors find cancer. PET stands for ‘positron emission tomography’.
A positron emission tomography scan. A scan in which a person is injected with a small amount of radioactive glucose solution. Cancerous areas show up brighter in the scan because they take up more of the glucose.


Someone who helps a person’s body get stronger after they have been sick.
A health professional who helps people recover their physical abilities after illness and surgery.


What the doctors think might happen after the treatment – i.e. how soon someone will get better.
The likely outcome of a disease. This helps doctors decide on treatment options.


Someone who helps people keep their minds healthy.
A health professional who helps people with their thoughts, feelings and behaviours.

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Q – Z words


radiation oncologist
A special doctor who uses x-rays that go into the body to kill cancer cells and make the cancer smaller.
A specialist doctor who prescribes radiotherapy and organises the treatment.

radiation therapy
Invisible beams called x-rays that go into the body to kill cancer cells and make the cancer smaller.
The use of radiation in the form of x-rays to kill or injure cancer cells so they can’t grow or multiply. This is different to when you get x-rayed to see inside you (e.g. for a broken leg).

When cancer comes back and the person feels sick again.
When cancer comes back after a period of improvement.

When cancer goes away after treatment.
When cancer cells and symptoms disappear because of treatment. Remission doesn’t mean the cancer is cured, but it is now under control.


side effects
Treatment can stop good cells from working, as well as bad cells. This can sometimes cause problems for the person with cancer, such as feeling tired, feeling sick or losing their hair. Most side effects go away after a while.
Unwanted effects of treatment, such as nausea, hair loss, rash or fatigue. They occur because treatment damages the cancer cells and some healthy cells as well, but the healthy cells usually recover after a while (e.g. hair grows back).

When the doctor tells the person how sick they are.
The extent of the cancer and whether it has spread from an original site to other parts of the body.

stem cell transplant
Stem cells are cells that make new blood in our bodies. Sometimes a person’s cancer has to be treated with such strong medicine that their stem cells are destroyed. The person is given new stem cells to make them healthy again.
A treatment in which diseased blood cells are destroyed by high-dose chemotherapy or radiation therapy, then replaced with healthy stem cells. Stem cells are obtained from either the bone marrow or blood of the patient or a donor.

When someone has an operation and a special doctor cuts out the cancer.
An operation by a surgeon to remove the cancer from the body.

What people feel (e.g. sore, itchy) or see (e.g. redness, a lump) when something’s not right in their body.
Changes in the body caused by an illness, such as pain, tiredness, rash or stomach-ache. These help the doctor work out what is wrong.


targeted therapies
Special medicine that damages or kills cancer cells, but doesn’t harm healthy cells.
Treatments that attack specific weaknesses of cancer cells while minimising harm to healthy cells. Two types of targeted therapies are small molecule drugs and immunotherapies.

A lump in the body that shouldn’t be there. The lump may or may not be cancer.
A lump in the body caused by uncontrolled growth of cells. A tumour can be benign (not cancer) or malignant (cancer).


A test that allows doctors to look inside the body so they can work out if anything is wrong.
A scan that uses soundwaves to create a picture of part of the body. It helps show where and how big a tumour is.

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This information was last reviewed in December 2015
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