Side effects of children's cancer treatment

If your child is being treated for childhood cancer we have information on side-effects that may be helpful. 

Side effects

A close crop showing a child facing away from camera wearing lilac hoody being comforted

The side-effects your child might get depend on the type of treatment, the dose, how long they have treatment for and how their cancer is affecting their body. 

How long will side-effects last?

Side-effects may happen straight away, 7-10 days following treatment or even months or years later.  

Usually any side effects from chemotherapy are worse just after treatment and improve towards the end of the rest period, just before the next chemotherapy treatment is due.

Some side-effects can last for a long time or even be permanent. It is also possible for side-effects to develop and persist some time after treatment is completed. These are called late side-effects and will require ongoing follow-up.

Will my child definitely get side-effects from treatment?

Not all children will get side-effects, but many do. Your doctor or nurse will discuss any possible side-effects with you before treatment. You can read about the different treatments to find out more about possible side-effects.

If you have any worries about your child, always let your medical team know.

Some common side-effects and symptoms are listed below, but your child may experience others not listed.

Some cancer treatments and some types of cancer can leave children more at risk of infection. They will need to take extra care to avoid infection. 

Read more

Anaemia is when the number of red blood cells is lower than it should be. Anaemia can happen if the bone marrow, which makes red blood cells, is affected by cancer or cancer treatments.

Read more

If your child’s platelet count is low (thrombocytopenia) they will be more likely to bruise and bleed. 


Read more

Some cancer treatments can cause hair loss or hair thinning. Hair usually grows back once treatment has ended.

Read more
 

Some children's cancer treatments can cause a sore mouth (mucotisis).


Read more

Your child may feel very tired and lacking in energy during and after treatment. 

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When you’re coping with your child’s cancer diagnosis, it may be hard to think about how their treatment might affect their ability to have children in the future (their fertility).

But it’s important to talk to your child’s healthcare team about whether their treatment might affect their fertility. For example, certain chemotherapy medicines may affect your child’s fertility. Radiotherapy to the tummy / pelvis area may also cause infertility.

Read more

Constipation and diarrhoea may be a side effect of childhood cancer treatment 

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Some cancer treatments may cause your child to feel sick (nausea) or to get sick (vomit). 

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Many things can affect your child’s appetite when they have cancer. For example, feeling sick (nausea), food tasting different, pain, constipation or having a sore mouth. Fatigue, anxiety and depression can also affect your child’s appetite.

Read more

Our supports

A childhood cancer diagnosis affects the whole family. We have lots of resources to help you cope practically and emotionally here. 

We also have a range of supports and services that can help please just reach out today. 

See all services 

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Adolescents and young adults

Are you an adolescent or young adult with cancer?

We have lots of services and information available to help you cope with a cancer diagnosis as a young person. 

Talk to a Cancer Nurse

Support Line

Support Line

Our Cancer Nurses offer confidential advice, support and information for anyone affected by cancer. Call or email supportline@irishcancer.ie. Video calls available. Mon-Fri: 9am-5pm
Support Line

In-hospital support

The Irish Cancer Society's Children’s Cancer Nurse at Children’s Health Ireland at Crumlin Hospital one day per week provides free, confidential advice, support and information to anyone affected by a child’s cancer.
In-hospital support