Letter to the Editor: Could Radioactive Iodine Be a Preferred Therapy for Graves' Hyperthyroidism Patients with Large Goiters? A Viewpoint from China

Dear Editor:

Since the publication of the first American Thyroid Association (ATA) guidelines for hyperthyroidism, ¹ their influence has gradually increased worldwide, including in China. We understand that radioactive iodine (RAI) was not recommended as a preferred therapy for Graves' hyperthyroidism with large goiters in the 1995, 2011, and 2016 ATA guidelines. ^{1 –3} As such, we believe that many physicians avoid using RAI for treatment of hyperthyroidism with large goiters, even in patients who have surgical contraindications or are unwilling to have surgery. This could lead to recurrence or exacerbation of the disease, due to ineffective control by antithyroid drugs.

However, after reviewing the ATA guidelines and their citations, we respectfully disagree with some points related to management of hyperthyroidism with large goiters.

The 1995 ATA guidelines stated that surgery is specifically indicated for patients with large goiters who may be relatively resistant to ¹³¹I. ¹ Similarly, in the 2011 and 2016 guidelines, large goiters (≥80 g) were considered a situation favorable for surgery but not for RAI. ^2,3 Among the three ATA guideline editions, these recommendations were not supported by any citations.

Moreover, regarding the management of Graves' hyperthyroidism in child and adolescent patients, the 2011 and 2016 guidelines proposed that surgery may be preferable to RAI with large goiters (>80 g), based on two studies by Peters et al. ^4,5 Peters et al. reported that only 20% patients with large thyroid (volume >60 mL) were cured by RAI, but this phenomenon was attributed to inadequate doses instead of “poor response.” ⁵

Furthermore, the ATA guidelines suggested that there is a tendency to underestimate thyroid size and thereby administer insufficient RAI to patients with large goiters. ^2,3 However, underestimation was mainly due to palpation or scintigraphy, while ultrasound has greatly improved the accuracy in determining thyroid volume. ⁴ It is worth noting that thyroid ultrasound is highly accessible.

Lastly, based on their findings, Peters et al. strongly suggested that RAI is preferable to surgery for Graves' disease, even in patients with substantial thyroid enlargement. ⁴ Thus, the recommendations from the ATA guidelines may be discordant with the authors of the cited studies.

The 2018 European Thyroid Association Guideline suggested that RAI is not contraindicated for large goiters, even if partially retrosternal or intrathoracic. ⁶ We believe that RAI should be a preferred therapy for treatment of Graves' hyperthyroidism with large goiters (>80 g) in adult and adolescent (≥15 years of age) patients. We hope that future iterations of the ATA guidelines may specifically reconsider this issue. Furthermore, more studies are needed, comparing the outcomes of different treatment modalities for Graves' hyperthyroidism with large goiters.