Levothyroxine to prevent underactive thyroid after radiotherapy in children with cancer

AI summary

From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.

The trial is looking for children and young patients with medulloblastoma, Hodgkin lymphoma or non-Hodgkin lymphoma who are about to have radiotherapy that includes the thyroid. It tests whether levothyroxine can protect the thyroid from hypothyroidism.

Sex

All sexes can join.

Disease stage

Medulloblastoma, Hodgkin lymphoma or non-Hodgkin lymphoma, before radiotherapy planning that includes the thyroid gland.

Earlier treatment

No radiotherapy including the thyroid yet. No earlier primary or secondary hypothyroidism.

Main reasons for not taking part

• Radiotherapy including the thyroid already done
• Earlier primary or secondary hypothyroidism
• No signed consent

The registry criteria, word for word

What the trial wants to find out

To offer the possibility of a treatment that could achieve a meaningful reduction in the incidence of post-radiation therapy hypothyroidism. Thyroid dysfunction may develop from a few months to several years after patients have completed their radiation treatment. In children with chronic diseases, or given lengthy anti-neoplastic treatments, recurrent or persistent endocrine disorders may have a negative effect on growth and development into adulthood.

The 2 groups in the trial

• TSH suppression during irradiationTreatment being tested

  From 14 days beforehand and throughout their RT, patients in the experimental arm will receive L-thyroxine in the morning, starting with 1-2 μg/kg, and adjusting the dose every 3 days to ensure TSH \< 0.3 μIU/mL before RT beginning. The 0.3 μIU/mL threshold is just below normal range not causing hyperthyroidism, and is defined as "mild" TSH suppression. Based on hormone status, L-thyroxine doses will be gradually increased to patients' individual minimum TSH-suppressive dose before starting RT, maintained throughout the treatment, then rapidly tapered off and stopped. During radiation treatment course will be checked twice a week for serum FT3, FT4, TSH assays in order to maintain TSH \< 0.3 μIU/mL, possibly without exceeding normal levels of FT3 and FT4. Once a week patients will also have a full visit and any other blood examination according to protocol in use and Institutional practice.

  Treatment: Levothyroxine

• Any TSH suppression during irradiationNo study treatment, for comparison

  Patient in the standard arm will perform radiotherapy treatment without any TSH suppression. At the end of radiation they will do serum FT3, FT4, TSH assay and then, after one year from RT, thyroid ultrasound + serum FT3, FT4, TSH assay.