Radioiodine therapy in benign thyroid disorders. Evaluation of French nuclear medicine practices.

Objectives: Radioiodine is currently used routinely in the treatment of hyperthyroidism including Graves' disease (GD), toxic multinodular goitre (TMNG) and toxic solitary nodule (TSN) but no consensus exists on the most appropriate way to prescribe iodine--fixed dose or calculated doses based on the gland size or turnover of (131)I. We carried out the first nationwide French survey assessing the current practices in radioiodine treatment of hyperthyroidism.

Material And Methods: A questionnaire was sent to French nuclear medicine hospital units and cancer treatment centres (n=69) about their practices in 2012.

Results: Euthyroidism was considered the successful outcome for 33% of respondents, whereas hypothyroidism was the aim in 26% of cases. Fixed activities were the commonest therapeutic approach (60.0% of GD prescribed doses and 72.5% for TMNG and TSN), followed by calculated activities from Marinelli's formula (based on a single uptake value and thyroid volume). The fixed administered dose was chosen from between 1 to 3 levels of standard doses, depending on the patient characteristics. Factors influencing this choice were disease, with a median of 370 MBq for GD and 555 MBq for TSN and TMNG, thyroid volume (59%) and uptake (52%) with (131)I or (99m)Tc. Even physicians using fixed doses performed pretherapeutic thyroid scan (98%).

Conclusion: This study shows that practices concerning the prescription of (131)I therapeutic doses are heterogeneous. But the current trend in France, as in Europe, is the administration of fixed doses. The study provides the baseline data for exploring the evolution of French clinical practices.