Decision Variables for the Use of Radioactive Iodine in Patients with Thyroid Cancer at Intermediate Risk of Recurrence

The use of radioactive iodine (RAI) after total thyroidectomy for patients at the American Thyroid Association (ATA) who are at intermediate risk of recurrence is controversial. This is due to the lack of prospective randomized trials proving a benefit to recurrence or survival of RAI therapy in this group. In the absence of such evidence, clinicians struggle to recommend for or against this therapeutic approach which frequently results in overtreatment. This review describes key elements in the decision-making process that help clinicians more comprehensively evaluate the need for RAI therapy in patients with thyroid cancer at intermediate risk of recurrence. A clear definition of the purpose of RAI therapy should be conveyed to patients. In this sense, adjuvant RAI therapy intends to decrease recurrence, and ablation therapy is used to facilitate surveillance. Better stratification of the intermediate risk category into a low-intermediate subgroup and an intermediate-high-risk subgroup results in less heterogeneity and a more precise prediction of recurrence risk. The evaluation of post-operative thyroglobulin levels may prevent the overtreatment of low-intermediate-risk patients when their thyroglobulin level is <2.5 ng/mL. the integration of tumor genomics (when available) alongside pathologic features can enhance the ability of the clinician to predict iodine concentration in thyroid cancer cells. Finally, a detailed consideration of the adverse effects of RAI, patients' comorbidities, and patient preferences will result in a patient-centered personalized approach. Systematic examination of these variables will ultimately provide a framework for making more educated decisions on the use of RAI in patients at intermediate risk of recurrence that will prevent overtreatment and minimize harm.