Korean Thyroid Association Guidelines on the Management of Differentiated Thyroid Cancers; Part I. Initial Management of Differentiated Thyroid Cancers - Chapter 6. Radioactive Iodine Treatment after Thyroidectomy 2024

ABSTRACT

The initial treatment for differentiated thyroid cancer includes appropriate surgery and radioactive iodine (RAI) therapy, followed by thyroid-stimulating hormone (TSH) suppression therapy as long-term management to prevent recurrence. RAI therapy following thyroidectomy has the three main purposes: remnant ablation, adjuvant therapy, and therapy for known disease. To optimize the goals and targets of RAI therapy, postoperative disease assessment, determination of recurrence risk, and consideration of various individual factors are necessary. The objectives of RAI therapy are determined based on the individual’s recurrence risk, and the administered activity of RAI is then determined according to these treatment objectives. Adequate stimulation of serum TSH is necessary before RAI therapy, and recombinant human TSH is widely used because of its advantage in reducing the risk of exacerbation of comorbidities associated with levothyroxine discontinuation and improving patients’ quality of life. Additionally, reducing iodine intake through appropriate low-iodine diet is necessary. Whole-body scans are conducted to assess the disease status after RAI therapy. If planar whole-body scans are inconclusive, additional single-photon emission computed tomography (SPECT)/CT imaging is recommended. Over the past decade, prospective randomized or retrospective clinical studies on the selection of candidates for RAI therapy, administered activity, methods of TSH stimulation, and advantages of SPECT/CT have been published. Based on these latest clinical research findings and recommendations from relevant overseas medical societies, this clinical practice guideline presents the indications and methods for administering RAI therapy after thyroidectomy.