Radioactive Iodine-Refractory Differentiated Thyroid Cancer in the Elderly

Most common thyroid cancers are differentiated thyroid cancers (DTCs) and have papillary, follicular, or Hürthle cell morphology. Papillary thyroid carcinoma (PTC) is the most common malignant tumor of the thyroid gland. The incidence of DTC increases with age. While most of the patients with DTC have an excellent prognosis, the outcome can be poor when diagnosed in elderly patients.

Current treatment approach for DTC includes surgery, thyroid-stimulating hormone (TSH) suppression, radioactive iodine, external beam radiotherapy, or systemic treatments such as kinase inhibitors. Radioactive iodine therapy (RAI) is the primary first-line systemic treatment for advanced DTC. However, during the course of treatment, the tumor may become refractory to RAI. Elderly patients are more likely to be diagnosed with advanced disease that can be refractory to RAI.

The advent of TKIs (tyrosine kinase inhibitors) and their usage in RAI refractory disease has shown improved progression-free survival. These agents are, however, associated with increased toxicity. The variable nature of disease and toxicity associated with the systemic therapy makes it important to have an individualized approach to management, especially in the elderly population who can be more susceptible to toxicities.