Letter to the Editor From Edmundo Avila-Hipolito: “Long-term Effects of Radioiodine in Toxic Multinodular Goiter: Thyroid Volume, Function, and Autoimmunity” Free

Roque et al report in a retrospective cohort of patients with toxic multinodular (TNMG) goiter in which treatment with 15 mCi of radioiodine induced low hypothyroidism rates while providing high cure rates and significant volume reduction (1). We would like, however, to highlight some important issues.

In the study, almost 9 of every 10 patients included were diagnosed with subclinical TMNG and only approximately 10% with overt hyperthyroidism. This is important because the criteria for treatment recommended by the American Thyroid Association are for those patients with overt hypothyroidism (weak recommendation, moderate quality of evidence) (2-4) and not subclinical hyperthyroidism for which the body of evidence is scarce regarding the risk of benefit and harms. In fact, multiple studies demonstrate that in patients with TNMG, the progression rate to overt hyperthyroidism is limited. Only 10% of the patients with an isolated low serum thyroid-stimulating hormone level progress to overt hyperthyroidism, and these levels normalize in 25% to 50% of patients with grade 1 subclinical hyperthyroidism (2-4). In addition, given the retrospective nature of the study, it is important to emphasize the potential influence of confounding factors (ie, iodine consumption, antithyroid drugs) that could have therefore biased the study outcomes. Furthermore, by year 1, ≥20% of the patients were lost; by year 6, 45% were lost; and by year 12, almost 100% were lost. Hence, while of value, we believe their results should be taken with caution.

Abbreviation

Abbreviation
 
• TNMG

  toxic multinodular goiter

Additional Information

Disclosure Summary: The authors have nothing to disclose.

References