Target therapies for radioiodine refractory advanced thyroid tumors.

A small but not irrelevant percentage of differentiated thyroid cancers become refractory to radioiodine treatment either because they lose the ability of taking up iodine over the time or because, despite a persistent uptaking ability, the effect of the radioiodine is lost in terms of tumor burden reduction. These patients receive only few and transient benefits from other conventional therapies and particularly from chemotherapy. In the last decade, several new drugs have been discovered as potentially useful and tested in clinical trials. They are mainly represented by protein kinase inhibitor molecules that should be proposed to advanced and progressive 131I refractory thyroid cancer patients by enrolling them in clinical trials or by the "off label" use of the drug.