Abstract
Patients with thyroid cancer usually have a favorable outcome following standard treatments (surgery, thyroid stimulating hormone suppression and radioactive iodine therapy) ; however, a few with radioactive iodine (RAI) -refractory differentiated thyroid cancer (DTC ; papillary and follicular), poorly or undifferentiated thyroid cancer and locally advanced or metastatic medullary thyroid cancer (MTC) show a poorer prognosis. Recently, several molecular-targeted drugs including tyrosine kinase inhibitors (TKIs) have been tested for those patients. Vandetanib demonstrated significant efficacy on progression-free survival for patients with advanced MTC in a phase III trial. It is approved by the United States Food and Drug Administration for use in advanced, symptomatic and progressive MTC in 2011. Now, some Japanese institutions are participating in ongoing global, multicenter phase III trials using sorafenib and lenvatinib for patients with RAI-refractory DTC. Patients receiving TKIs should be carefully monitored for distinctive adverse events, including hand-foot syndrome, hypertension, QT-prolongation, severe fatigue, hypothyroidism and so on. It is also imperative to develop proper biomarkers which can predict the efficacy of each drug in the respective patient.
