Parents and children affected by cancer

About children's cancer

Information about children's cancer including what kinds of cancer affect children.

What is cancer?

Cancer is a disease of the body’s cells. 
Cells are the building blocks of the body. As cells die off or wear out, new cells replace them. 

With cancer, the growth of new cells becomes faulty. The abnormal cancer cells multiply out of control.

The abnormal cells can affect the body in different ways.

  • Tumours (e.g. brain tumours): The abnormal cells can form a lump (tumour). Tumours cause medical problems in two ways:
    • Directly, by pressing on and damaging nearby organs.
    • Indirectly, by breaking off and invading other distant tissues and organs.
  • Blood (e.g. leukaemia): When cancer affects blood cells, abnormal blood cells build up in the bone marrow or blood. This can affect the way your body normally works and cause symptoms.
  • Lymphatic system (e.g. lymphoma): The lymphatic system is part of our immune system, which protects us from infection and disease and removes extra fluid and waste from the body’s tissues. It is made up of lymph nodes connected by tiny tubes called lymph vessels. Lymphoma cancers happen when lymphocyte white blood cells grow in an abnormal way. The abnormal cells collect in your lymphatic system, particularly the lymph nodes. This causes swellings, known as lymphomas.
  • Cancer is a word for many different diseases
    There are more than 200 types of cancer that affect different parts of the body in various ways and which need different treatments.
  • Cancers sometimes spread
    If a tumour is cancerous (malignant), a cell or group of cells can be carried by your blood or lymph fluid to another part of your body, where it can form a new (secondary) tumour. This is called metastasis. 

Why do children's cancers happen?

The cause of most children's cancers is still unknown but research is ongoing. It is important to remember that it's not your fault your child has cancer and it is not because of anything you have or haven't done. 

Unfortunately, there is nothing a parent can do to prevent childhood cancer, as the risk factors linked to childhood cancers are not things we can control. Having a risk factor doesn’t mean your child will definitely get cancer. Often children with no risk factors get the disease. 

Most cancers are not caused by an inherited faulty gene and it is very rare for another child in a family to develop cancer. Brothers and sisters do not usually need to be tested.

If you feel your child may be at risk, first talk to your family doctor (GP) about your concerns. He or she may advise you to visit a specialist. 

Cancer is not infectious and cannot be passed on to anyone who comes into contact with your child.

Childhood cancer in Ireland statistics infographic thumbnail

Risk factors for children's cancer

  • Inherited medical conditions. Children with inherited conditions such as Down syndrome are more at risk of developing childhood leukaemia, but it is still very rare. 
  • Development in the womb. Rarer tumours such as Wilms tumour and retinoblastomas are believed to develop while the child is still in the womb. 
  • Infection. Epstein Barr virus (EBV) is a common infection among children. It is thought that EBV can contribute to the development of certain types of lymphoma. 
  • Previous cancer treatment radiotherapy. Children who have been treated with radiotherapy or chemotherapy for cancer in the past have a slightly higher risk of getting another cancer in the future.

What kinds of cancer affect children?

It is rare for children to get cancer. Children's cancers affect approximately 200 children and teenagers under the age of 16 each year in Ireland. The most common cancers that affect children are: 

  • Leukaemia. This is a type of cancer that affects the blood and bone marrow. White blood cells, which are important for fighting infection, are made in the bone marrow. Bone marrow is the spongy material in the centre of your bones where blood cells are made. With leukaemia, the body makes too many abnormal white blood cells. About 1 in every 3 cancers that affect children are leukaemia. There are 4 main types of leukaemia - acute lymphoblastic leukaemia (ALL), acute myeloid leukaemia (AML), chronic myeloid leukaemia (CML) and chronic lymphocytic leukaemia (CLL).
  • Brain tumours. Cancer that causes a tumour (lump of abnormal cells) in the brain. The brain, together with the spinal cord, controls all the functions of the body. Some brain tumours are benign (not cancer), while others are malignant (cancer). The most common types are astrocytoma, medulloblastoma and ependymoma.
  • Sarcoma. Tumours that develop from tissue such as bone, muscle, fat or cartilage. They can occur in any part of the body and include soft tissue sarcomas, rhabdomyosarcoma and bone tumours, such as Ewing sarcoma and osteosarcoma.
  • Gonadal and germ cell tumour. Germ cells are normally found in the embryo that develops into a baby in the womb. These cells in time mature into sperm or egg cells in the testicles or ovaries. Some of the cell may remain in different parts of your child's body after birth and may develop into tumours. These tumours are known as germ cell tumours or embryonal tumours. Gonadal germ cell tumours start and stay in the child's reproductive organs (testicles or ovaries).
  • Lymphoma. Cancer of the lymphatic system, which is part of your immune system. The immune system helps our body to fight infection and disease. There are two main types - Hodgkin and non-Hodgkin lymphoma.
  • Hepatic tumours. Cancer that affects the liver. The liver helps blood to clot, breaks down fats and carbohydrates from our food and gets rid of harmful substances from our body. The most common types of malignant tumours in the liver are hepatoblastoma and hepatocellular carcinoma.
  • Neuroblastoma. A rare cancer that affects special nerve cells. These cells help develop the nervous system and other tissues.
  • Retinoblastoma. A malignant tumour at the back of the eye. It develops in the cells of the retina, which is the part lining your eye that is sensitive to light. 
  • Nephroblastoma. Renal tumours affect the kidneys. The kidneys filter your blood to remove waste products. The most common type that affects children is called Wilms’ tumour. It is also called a nephroblastoma.
  • Other epithelial and melanomas. Includes rare tumours of the head and neck (nasopharyngeal carcinoma) and the skin (melanoma).

Children's cancer tends to occur in different parts of the body to adult cancers. They also look different under the microscope and respond differently to treatment. Cure rates for children are much higher than for most adult cancers. 

There have been huge improvements in cancer treatments for children in the past 50 years. As a result, more children than ever are surviving cancer. Some forms of cancer are now completely curable. Research is also continuing to improve treatments and reduce side-effects.

For more information

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