Low Iodine Diet advice in the UK prior to radioiodine ablation for differentiated thyroid cancer: An observational study

Summary

People with thyroid cancer are often treated by thyroid removal, followed by radioactive iodine to kill any remaining thyroid tissue (ablation). If there is a lot of iodine in the body at ablation it might interfere with the take up of radioactive iodine by remaining thyroid cells. This means people are usually asked to cut out foods containing iodine for 1-2 weeks before ablation. Many UK hospitals give advice about foods to eat and foods to avoid using diet sheets. However, we do not know if patients follow advice and lower their iodine intake and we are not sure whether reducing iodine status really does improve ablation success. This grant will support an application to the National Institute for Health Research for funding to observe current practice to find out if advice to follow a low iodine diet reduces iodine intake and status. We will recruit patients with thyroid cancer from different hospitals in the UK. We will measure iodine in urine and ask them to complete a short iodine-specific food questionnaire before they make any changes to their diet and immediately before ablation. We will also examine whether there are differences in ablation success between patients with lower or higher iodine status at the time of ablation. The study will show whether people lower iodine intake and status before ablation. If they do not, we will need to develop better ways of giving low iodine diet advice. However, if iodine status is not linked to ablation success, we will need to question whether the advice is necessary.

Updated 30/12/2021