Molecular Radiotherapy Series No. 6 - Information for parents of children and young people having radioactive iodine (131I) treatment

We want to involve you and your child in all the decisions about their care and treatment. If you decide to go ahead with treatment, by law, we must ask for your consent and will ask you to sign a consent form. This confirms that you agree to your child having the procedure and understand what it involves.

Staff will explain all of the risks, benefits and possible alternatives before they ask you to sign a consent form. If you are unsure about any aspect of your child’s proposed treatment, please do not hesitate to speak to speak to the team looking after your child.

Radioactive iodine (131 I) is a form of radiotherapy treatment called molecular radiotherapy (MRT). It has been used to treat thyroid cancer for many years. It is a targeted method of destroying any remaining normal thyroid tissue or thyroid cancer cells that may remain following your child’s total thyroidectomy surgery.

The thyroid gland and related cells need iodine in order to work. They take up any iodine in the body. This then releases radiation in the parts of the body where it has been absorbed, providing an easy way to target the radiation to areas in the body where it is needed. Radioactive iodine ( 131 I) treatment together with surgery will maximise the chances of eradicating your child’s cancer.

The need for treatment depends on the risk that your child’s cancer might progress after surgery. It is not needed for very tiny cancers which have been removed.

It is certainly needed in high-risk patients where the disease has spread. Some patients with lower risk may choose not to have this treatment. However, this is something that you should discuss with the clinical oncologist treating you before making a decision.

At the first visit you and your child will meet the consultant clinical oncologist who will talk to you about the plan for their treatment and explain what to expect. You will also meet the other members of the medical team who will be treating your child. You and your child will have a chance to ask any questions you may have at this appointment.

We will take you to the paediatric oncology ward (T11N) to meet some of the nurses who will be looking after your child. We will show you the protected rooms in which your child will be staying for the duration of their treatment. You will also meet the molecular radiotherapy team who will coordinate your child’s care and treatment.

Visiting the ward and treatment rooms, and meeting the staff involved in your child’s care, will give you a better understanding of what to expect and ensure your child is comfortable and familiar with what is happening (Fig 1.).

We can contact the play specialists in advance to ensure toys and activities your child enjoys are available in the room for the duration of your child’s stay.

For a good uptake of radioactive iodine (131I), your child’s blood levels of thyroid stimulating hormone (TSH) need to be high. To stimulate their levels of TSH, they will need to stop certain medications or have injections to ensure their treatment is effective. The doctor will advise which method is best for them.

Patients are given injections of rhTSH (thyrotropin alfa), also known by the trade name of Thyrogen. These allow your child to carry on taking their thyroid medication throughout treatment and are given as outpatient appointments before treatment.

However, not all patients are suitable, or able to have Thyrogen injections. If this is applicable to your child, they will need to stop your Levothyroxine Sodium (T4) four weeks before admission or your Liothyronine (T3) ten days before admission. Your child may feel tired or weak when not taking the tablets. This is normal and the symptoms will disappear once they start taking the tablets again, which is normally on discharge from hospital. 

Two weeks before admission your child should avoid iodine-rich foods. Eating these foods may reduce the effectiveness of treatment. We advise that they:

• Do not eat fish, kelp and all seafood.
• Do not take vitamin supplements which contain iodine or cod liver oil.
• Do not take cough medicine, iodised table salt or sea salt.
• Do not eat foods artificially coloured pink or red such as canned and glacé cherries, canned strawberries, spam and salami. These contain the colouring material E127 which is rich in iodine.
• Certain CT scans use iodine-based contrast – if you are having a CT prior to treatment please inform your doctor or the MRT radiographer booking your treatment. If you have had a recent CT scan with iodine-based contrast your treatment will be delayed for three months.

Please continue taking any other medications that they have been prescribed, and bring a supply with you on admission and show them to the doctor who examines your child.

Your child should not have radioactive iodine (131I) treatment if they are pregnant or breastfeeding. You must tell the staff if there is any chance of them being pregnant.

All individuals with internal reproductive organs (a uterus) over the age of 12 will have a pregnancy test before treatment starts. Your child should not become pregnant for at least six months after treatment. Individuals with external reproductive organs (testes) should not conceive a child for at least four months after treatment.

The MRT radiographers will discuss any issues around sex, contraception and intimacy with your child if it is appropriate.

Your child will be admitted to the paediatric oncology ward on the 11th floor of the main UCH building (T11N) on the day of their treatment and allocated a protected room with en-suite shower and toilet (Fig. 2).

There is available space outside the room, to allow you to stay in hospital with your child for the duration of his/her treatment. (Fig.3, Fig.4).