The prevalence of hyperthyroidism is 2% of women and 0.2% of men in the UK. Recent evidence indicates that the incidence of Graves’ disease, the most common cause of hyperthyroidism, has doubled between 2000-2002 and 2017-2019 (from 33.6 /100,000 person years to 66.2 /100,000 person years, Lancet 2023 PMID: 37156255).
Up to 25% of patients with hyperthyroidism develop significant thyroid eye disease (TED), which may be elicited or worsened by radioactive iodine (RAI) administration, especially in smokers. A number of promising new treatments for TED have recently been explored in clinical trials. It would be beneficial for health care professionals and patients to understand these better and the outcomes received from prescription of these treatments.
Approximately 30% of people with hyperthyroidism are treated with radioactive iodine, the other commonly used modalities being antithyroid drugs and surgery. We anticipate that this number will increase following the 2019 NICE guidelines.
We don’t have good data regarding the number of doses of radioiodine currently given annually in the UK since these data are not well recorded. There are published data that in 1982 there were 8,000 doses of RAI given and in 2003 there were 10,000 administered (DTB June 2006).
Radioiodine has been used to treat hyperthyroidism for more than 8- years and is generally considered a safe treatment. More recently some studies have indicated a possible link to development of solid cancers, especially at higher doses (JAMA Netw Open 2021 PMID: 34533571)
Radioiodine is the NICE recommended treatment for most cases of hyperthyroidism. Current uncertainty about risks of RAI therapy (conflicting studies on cancer risk and patient fears about development of hypothyroidism) deters some patients from taking the therapy. A prospective database with ascertainment of new cancer diagnosis as well as morbidity and mortality through NHS-CR (digital) would inform this over a 5 and 10 year period, leading to improved patient confidence. Data regarding radioiodine administration and long term outcomes are particularly sparse in the younger age group. Retrospective and prospective data extraction of patients with hyperthyroidism treated with radioiodine, antithyroid drugs and surgery will highlight a combination of the impact of lifestyle habits, the treatment modality used for hyperthyroidism, the use of prophylactic steroids and radioiodine dosing on TED.
