Sorafenib emerges as option for advanced thyroid cancer

Overall, thyroid cancer is very treatable and has an excellent prognosis. However, a subset of patients with thyroid cancer has disease that is resistant to radioactive iodine, and for those patients, especially those with metastatic disease, we have very limited treatment options. Traditional chemotherapy has had little to no efficacy against most thyroid cancers, leaving patients with the only option of enrolling in a clinical trial.

Dr. Rebecca Sippel

Thankfully, several phase II clinical trials of multikinase inhibitors have recently shown partial response rates in up to 50% of patients. Sorefenib is the first of these drugs to move on to a phase III clinical trial. This study showed disease stabilization in over 50% of patients and a significant improvement in progression-free survival (10.8 vs. 5.8 months). The results of this study will hopefully lead to sorafenib being the first FDA-approved treatment for radioactive iodine-resistant thyroid cancer, which will be a welcome addition to those of us treating patients with advanced thyroid cancer.

While the results of this study are exciting, it is clear that this is not going to be a cure for metastatic thyroid cancer. As with all multikinase inhibitors, not all patients will respond, and of those that do, it is likely that they will develop resistance to treatment, and that the benefits will not be long-standing. Therefore it is important that we continue to pursue our efforts to examine other drugs that have shown efficacy in early studies and also try to better understand the mechanisms behind multikinase drug resistance, so that we can continue to provide treatments and hope to our patients with radioactive iodine-resistant thyroid cancer.

Rebecca S. Sippel, M.D., FACS, is chief of endocrine surgery, department of surgery, University of Wisconsin-Madison.