Optimizing therapy for radioactive iodine-refractory differentiated thyroid cancer: current state of the art and future directions.

The majority of patients with differentiated thyroid cancer are cured with standard primary treatments including surgery, radioactive iodine and TSH suppression. A small proportion of patients who develop radioactive iodine-refractory metastatic disease have few treatment options. Recent discovery of the molecular mechanisms that contribute to thyroid cancer tumorigenesis and its progression have revealed key targets that are currently being evaluated in clinical trials. In the last decade several novel targeted therapies have shown encouraging results and have brought hope to patients with advanced disease. However, identifying the subpopulation of patients who may benefit from systemic therapies remains a challenge as the use of these therapeutic modalities is associated with high toxicity rates and most patients have a long indolent phase where the tumor is stable or slowly progressive and asymptomatic. The objective of this review is to summarize the management of patients with metastatic, radioactive iodine refractory differentiated thyroid cancer.