What is children's cancer?

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The word ‘cancer’ can be scary. You may know someone who had cancer who became very ill, or even died. While cancer does claim the lives of thousands of Australians every year, not everyone who gets cancer will die. Most children diagnosed with cancer are treated successfully and go on to live fulfilling lives.

Feeling shocked, afraid and confused is a normal part of receiving a cancer diagnosis, especially when a child is diagnosed. However, understanding the disease and knowing what to expect will help you manage some of these feelings.

Cancer is a disease of the cells, which are your body’s basic building blocks. Cells divide and form new cells all the time to replace old, or dead cells. For example, new skin cells replace old skin cells when they die. This process happens throughout your whole body.

Most of the time, cells divide and grow normally and will stop growing when they need to. However, sometimes they don’t. Cancer starts when a cell becomes abnormal, and then grows and multiplies in an uncontrolled way. Cancer cells usually group together and form a lump. This is called a tumour. Some tumours are benign (non-cancerous) and some tumours are malignant (cancerous). Malignant tumours can damage or invade the surrounding tissues. Sometimes, cancer cells from a malignant tumour can spread to other parts of the body, causing further damage.

Cancer is not one condition. It’s a word that refers to different conditions that:

  • affect different cells and tissues in the body
  • behave in different ways
  • respond differently to treatments

Metastatic tumours

The site where the cancer starts is called the primary site and the tumour that initially forms is called the primary tumour. Sometimes tumours spread to other parts of the body and form new tumours. These are known as metastatic tumours. The new tumours that form are called secondary tumours or metastases.

Benign tumours

A benign tumour is not cancer. Cancer refers to malignant tumours. 

A tumour is benign if it:

  • grows only in one place
  • does not invade surrounding tissues 
  • does not spread to other parts of the body. 

However, a benign tumour can still cause some problems, and doctors will need to keep an eye on it.

Differences between childhood and adult cancers

The types of cancers that occur in children can be different from cancers that occur in adults. Children’s cancers:

  • can look different under the microscope
  • start in different parts of the body 
  • are treated differently
  • respond differently to treatment. 

Children often respond better to treatment than adults. This could be because1:

  • the cancer itself is different
  • children may get more intense treatments
  • children don’t have any other health problems, or comorbidities (other health conditions), like many adults do.

Specialised children’s cancer centres treat most children with cancer in Australia. The doctors and other staff at these centres know the differences between adult and childhood cancers. They also understand the unique needs of children with cancer and their families.

Types of children’s cancer

In children, cancer tends to affect fast-growing tissues such as:

  • blood
  • lymph
  • bone marrow
  • nervous tissues
  • muscles
  • kidney
  • liver 
  • bone.

You can find more information on the types of cancers that affect children on our page Types of Children's Cancers

Causes of cancer in children

It’s not always clear why some people get cancer, and some don’t. In most cases, we don’t know why children get cancer. 

Sometimes, tumours develop as a result of a genetic error made while a child’s body is growing. 

Some childhood cancers run in families. Some children are born with genetic conditions that increase their chance of getting certain cancers. This is known as a risk factor.

A risk factor is anything that increases a person’s chance of getting a certain condition. However, children are too young to have the same risk factors for cancer as adults, such as smoking or drinking too much alcohol. 

Even if your child has a risk factor, it doesn’t mean they will develop cancer. Many children with a risk factor will never develop cancer. And others with cancer may have had no known risk factors. Even if a person with a risk factor develops cancer, the risk factor may not have had much to do with it.
 
What we do know is that if a child develops cancer, it’s not because of something they, or their parents did or did not do to cause it.

What does not cause cancer?

Cancer is not caused by accidents such as a bump on the head, or by anything you or your child did or did not do. 

Cancer is not contagious. A child can’t ‘catch’ cancer from someone else like chickenpox or the flu.

If your child has cancer, it’s no one’s fault, and no one is to blame.

General symptoms of cancer

Many things – including common infections – can cause similar symptoms to cancer in children. This can make cancer hard to diagnose. 

Symptoms of cancer can include:

  • easy bruising, or bruising that doesn't go away
  • an unusual lump, bump or swelling
  • unexplained paleness, tiredness, loss of energy and loss of interest in things
  • pain in one area of the body that doesn't go away
  • limping or difficulties moving around
  • unexplained fever or illness that doesn't go away
  • frequent headaches, often with nausea or vomiting
  • visual changes, such as blurred vision
  • lack of balance or direction when walking that doesn’t go away
  • unexplained weight loss.

If your child has any of these symptoms, it doesn't mean that they have cancer. However, if your child has any of these symptoms that don't go away quickly, it's important to have a check-up with your child's doctor. 

If your doctor thinks your child might have cancer, your child will have more tests. 
 
You can read more about this at Diagnosing children's cancer.
 
You can find more information on symptoms for different types of cancer at Types of Children's Cancers.

How common is childhood cancer?

In 2020, it is estimated that 870 Australian children will be diagnosed with cancer. It is a significant health issue.

Surviving children's cancer

Children have great capacity for healing and many children with cancer are cured. In addition, there have been huge improvements made in childhood cancer treatments. For example, in the 1980s, around 73% of children diagnosed with cancer were alive for 5 years after their diagnosis. Today, around 85% of children are successfully treated and become long-term survivors.

Further information on survival rates can be found at our Statistics for children's cancer page.


References

[1] https://www.cancer.org/cancer/cancer-in-children/differences-adults-children.html