Endocrine Abstracts

Background: Before radioiodine (RAI) therapy patients undergo a technetium 99m thyroid uptake scan and anti-thyroid medication is stopped prior to treatment following clinical review with the nuclear medicine team. Once treated, patients are followed up in the post-radioiodine telephone clinic. Thyroid function is checked at 3, 6, 9 and 12 weeks. Levothyroxine is started once the fT4 is <14 pmol/l.

Purpose: To assess success rates 1 year post RAI treatment, between January 2015 and January 2021.

Methods: Electronic patient records were reviewed, information included demographics, diagnosis, percentage of uptake on pre-treatment scan, dose of RAI, blood results and time to ‘cure’.

Results: 257 patient records were reviewed, two were excluded due to loss of follow-up and six were excluded as a second RAI had been given during the analysis period Of these patients, 30% were euthyroid or hypothyroid at 3 weeks, this proportion rose to 75% at 9 weeks and 96.4% at 1 year and 3.6% remained hyperthyroid. The failure rate for Grave’s disease was 3% and response time was similar for males and females. 7.4% of Toxic Multinodular Goitre and 3% of autonomous nodule treatments failed but responders did so at 7-9 weeks

Conclusions: The RAI service at Imperial College Healthcare demonstrates better than average cure rates at one year than is reported in the literature, 96.4% vs 85-94%. Rapid results were demonstrated, with 75% of patients becoming hypothyroid or euthyroid within 9 weeks but RAI had higher failure rates in those with TMNG and females with Grave’s. The findings should encourage clinicians to recommend RAI as a first line treatment for thyrotoxicosis, as suggested by NICE guidelines.