RAI-Refractory Differentiated Thyroid Cancer with Multiple Organ Progressive Disease

Abstract

Effective treatment options have greatly increased during the past 10 years for patients with progressive, radioiodine-refractory metastases from differentiated thyroid carcinoma. As clinical trials of potential new therapies were initiated, consensus definitions of “radioiodine-refractory” and “progressive” disease were required, which can be readily applied in routine clinical practice. Antiangiogenic drugs such as multitargeted kinase inhibitors have been extensively studied in phases II and III trials, demonstrating as a class of agents that this approach to treatment can provide significant improvement in progression-free survival. More selectively targeted therapies, aimed at kinases that signal along proliferation pathways, also may have a role to halt progression of disease. Of interest and now intensely studied is the observation that some selective kinase inhibitors may permit restoration of radioiodine responsiveness, thus providing a basis for reintroduction of radioiodine therapy. Finally, locally administered therapies such as stereotactic radiation and antiresorptive therapies can be valuable for management of skeletal metastases. Toxicities of these therapies can be considerable, but judicious and expectant management can permit patients to benefit from long-term stabilization of metastatic disease.