Glitazone treatment does not cause side effects in patients with metastatic thyroid cancer

Repeated radio-ablation therapy with iodine-131 to treat metastatic thyroid cancer can be less effective than the initial round of treatment due to de-differentiation of the cancer cells as the disease progresses, making them less sensitive to I-131. Glitazones, a class of PPARg drugs capable of re-differentiating the cancer cells, can enhance their I-131 uptake. Long-term use of these agents for treatment of diabetes has been linked to cardiovascular side effects.

Devendra Wadwekar, MD, and coworkers from the University of Utah - Salt Lake City studied the effectiveness of a short, 6-week course of rosiglitazone and pioglitazone prior to radioiodine therapy in patients with metastatic thyroid cancer, including patients whose cancer had spread to the lungs. According to data presented today at the 81st Annual Meeting of the American Thyroid Association (ATA), short-term glitazone treatment caused no side effects. In 38% of patients, I-131 uptake by metastasized cancer cells in the lung increased significantly compared to no or low uptake in previous rounds of radio-ablation therapy. Additionally, thyroglobulin levels were reduced in the blood of all patients that received glitazone pre-treatment, suggesting a decrease in metastatic disease. Long term efficacy and survival remains to be determined.