Novel chemotherapy options for advanced thyroid tumors: small molecules offer great hope

Endocrine tumors are often overlooked in medical oncology discussions, as many of them are effectively cured by surgery alone or surgery plus an ablative radiation therapy. For the rare aggressive endocrine cancers that are widely metastatic or rapidly progressive, however, the role of the medical oncologist becomes more important. To date, conventional chemotherapy has not had a significant impact on the natural history of these malignancies. This has led to the evaluation of novel compounds; some of which have already entered into randomized clinical trials. This review will focus on the advances made in the treatment of advanced thyroid cancer, the commonest of endocrine malignancies.

A growing understanding of molecular oncology has allowed the development of targeted agents in different types of thyroid cancer. Some agents presently being evaluated in clinical trials include inhibitors of angiogenesis (sorafenib, CA4P, axitinib and vandetanib), the epidermal growth factor receptor (gefitinib, vandetanib) and RET protein (vandetanib). Preliminary results from these studies will be reviewed in this paper.

The recent explosion of targeted agents available for study has generated enthusiasm for oncologists treating thyroid cancer. Antiangiogenesis strategies in particular appear promising. RET inhibition in medullary thyroid cancer is also being explored. Further clinical trials will determine which of these will enter the clinic in the near future.