Targeted therapy in refractory thyroid cancer: current achievements and limitations.

Thyroid cancer refractory to conventional treatments lacks effective treatment. Targeted therapy is an emerging therapeutic strategy for these cancers, based on preliminary promising results. Tyrosine kinase inhibitors target both specific oncogenic pathways involved in thyroid cancer progression and aspecific mechanisms such as neoangiogenesis. They are generally well tolerated and most adverse events have low-to-moderate severity. Other classes of drugs have been tested, alone or in combination with tyrosine kinase inhibitors, but so far the results have been limited. The aim of this article is to describe the benefits and limitations of innovative drugs that are currently under investigation in patients with refractory thyroid cancer.