Possible long-term side effects of cancer treatment on children

This information was written by the Children’s Cancer and Leukaemia Group (CCLG).

Most children won’t have any long-term effects. If they do occur, they happen because of the damage cancer treatment can cause to healthy cells in the body. These effects can occur as a result of surgery, radiotherapy, some chemotherapy drugs and bone marrow transplants.

Most problems result from chemotherapy or radiotherapy. They depend on four things:

  • type of treatment
  • site of treatment
  • dose of treatment
  • your child’s age during treatment.

Late effects may include problems with growth and development, heart, lungs, kidney function, hormones and fertility. Any identified late effects, monitoring or treatment required for your child will be explained in the follow-up clinic.


At the clinic your child will be regularly weighed and measured to check they are growing normally. Decreased growth during treatment is common. There is usually a period of ‘catch-up’ growth when treatment finishes.

Radiotherapy may have important effects on growth and development. It may affect growing bones, e.g. radiotherapy to the spine can mean your child will not grow as tall as expected or, if given to a limb, it may be shorter than the limb that has not been treated.

Radiotherapy to the brain may affect the pituitary gland which produces many hormones, including growth hormone. If your child does not produce enough growth hormone they will not grow properly so may be referred to an Endocrinologist (a specialist doctor in growth and hormones).

Sometimes a daily injection of artificial growth hormone is needed to help your child grow. Sometimes other hormones are affected, for example, thyroid hormone and cortisol. These can be replaced with tablets.

Puberty (sexual development)

Certain treatments may affect your child’s sexual development (puberty). These include:

  • radiotherapy to the brain
  • radiotherapy to the lower abdomen or pelvis, including the ovaries and testicles
  • total body irradiation (TBI) for a bone marrow transplant
  • certain chemotherapy drugs
  • surgery to the ovaries, womb or testicles.

All children are monitored carefully at the follow-up clinic for signs of puberty, especially if they had any of the treatments mentioned above. At the follow-up clinic, young people may be asked about normal body changes/puberty and may need to be examined.

  • Males - this may be an examination of the testes and penis, pubic, facial and underarm hair growth. This can be done by a male member of staff, if preferred.
  • Females - this may be an assessment of the stage of breast development, asking about periods, pubic and underarm hair growth. This can be done by a female member of staff, if preferred.

The follow-up teams appreciate this can be embarrassing for young people so they aim to handle this aspect of follow-up in a sensitive and discreet manner. If there appears to be any delay going into puberty some investigations will be done. Sometimes sex hormone therapy may be needed to help start sexual development. If there are problems they will be referred to an endocrinologist (hormone specialist).

Heart and lungs

Some chemotherapy drugs and radiotherapy can affect the heart and lungs. If your child has had drugs that affect the heart, they will need to have heart ultrasound scans (echocardiograms) during and at the end of treatment.

How much they receive will determine if these are repeated every 3 or 5 years. These scans will carry on for the rest of their lives and for young women these will be increased during pregnancy. Careful monitoring is important because there are often no symptoms. Your child will be referred to a cardiologist (heart specialist) if any problems are found. Sometimes it is necessary to do special tests on the lungs (lung function tests). This is usually following some types of chemotherapy, radiotherapy to the lungs and total body irradiation (TBI). These tests involve measuring lung volumes and are easy for a child to do.

Kidney tests

Removing one kidney does not usually cause any long-term problems, as the remaining kidney can cope alone. Certain drugs can cause kidney problems and if your child received these they will have had additional kidney tests during treatment. Kidney function will be checked occasionally at follow-up visits, either by a urine sample or a blood test, or both. It is important to have their blood pressure checked; this is usually done routinely at the clinic visit.


After treatment is finished and your child recovers there will be time to think about their future and growing up. This may lead you to think about them having a family of their own. There is a common belief any cancer treatment causes infertility. This is NOT true. Many children treated for cancer go on to have their own families. All types of cancer and leukaemia are treated differently and it depends on which treatment each child had how it will affect their fertility. You will be able to discuss this in more detail with the doctor or nurse specialist in the follow-up clinic.

Second cancer

A very small number of children who are cured of cancer can go on to develop another, different, cancer later on in life. There are two main reasons for this. Firstly, some cancer treatments can increase the risk of developing another cancer. Secondly, some families have a specific risk of developing certain cancers. This is very rare. Your doctor or nurse specialist will be able to discuss any worries you have about this.

Children's cancer information from CCLG

This information about children’s cancer was written by the Children’s Cancer and Leukaemia Group (CCLG). It has been reviewed and edited by their publications committee, which includes medical experts from all fields of children’s cancer and care.

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