New perspectives on the treatment of differentiated thyroid cancer.

Even though differentiated thyroid carcinoma is a slow growing and usually curable disease, recurrence occurs in 20-40% and cellular dedifferentiation in up to 5% of cases. Conventional chemotherapy and radiotherapy have just a modest effect on advanced thyroid cancer. Therefore, dedifferentiated thyroid cancer represents a therapeutic dilemma and a critical area of research. Targeted therapy, a new generation of anticancer treatment, is planned to interfere with a specific molecular target, typically a protein that is believed to have a critical role in tumor growth or progression. Since many of the tumor-initiation events have already been identified in thyroid carcinogenesis, targeted therapy is a promising therapeutic tool for advanced thyroid cancer. Several new drugs are currently being tested in in vitro and in vivo studies and some of them are already being used in clinical trials, like small molecule tyrosine kinase inhibitors. In this review, we discuss the bases of targeted therapies, the principal drugs already tested and also options of redifferentiation therapy for thyroid carcinoma.