Novel therapeutic approaches to improve thyroid cancer outcomes

Oct 30 2014

Novel therapeutic approaches to improve outcomes in thyroid cancer, for example using targeted delivery of cytotoxic drugs to tumor cells, will be among the topics featured in oral and poster presentations delivered at the 84th Annual Meeting of the American Thyroid Association, October 29-November 2, 2014, in Coronado, California. Researchers will also present the results of an updated analysis from a national study of thyroid hormone suppression therapy, and the potential survival benefit from combining lithium with radioiodine therapy in metastatic thyroid cancer.

Renata Jaskula-Sztul, Ph.D., University of Wisconsin Medical School (Madison), and colleagues will deliver an oral presentation entitled "Targeted Delivery of a Novel Histone Deacetylase Inhibitor, AB3, Using Unimolecular Micelles to Improve Antitumor Effect in Medullary Thyroid Cancer." MTC is a neuroendocrine tumor that accounts for 3-5% of thyroid cancers. Treatment includes surgical removal of the tumor and adjuvant therapies designed to target any remaining tumor cells locally or that may have metastasized to distant locations. The researchers describe the use of tumor-targeting micelles (unimolecular micelles conjugated with the somatostatin analog KE108) to deliver a novel antitumor agent, the histone deacetylase inhibitor AB3. They report that targeted delivery of the nanocarrier was associated with increased uptake of the micelles by MTC cells in culture and an improved cytotoxic effect, suggesting the possibility for better therapeutic outcomes and less systemic toxicity with this type of drug delivery approach in patients.

In the presentation "Long-Term Moderate Thyroid Hormone Suppression Therapy Is Associated with Improved Outcomes in Differentiated Thyroid Carcinoma: National Thyroid Cancer Treatment Cooperative Study Group Registry Analysis 1987-2012," a team of researchers provides an updated analysis of nearly 5,000 patients with differentiated thyroid carcinoma (DTC), evaluating their overall survival and disease-free survival based on their initial treatment (thyroidectomy, post-operative radioiodine [RAI]) and long-term TSH-suppressive thyroid hormone therapy (THST). Aubrey Carhill, M.D., The University of Texas MD Anderson Cancer Center (Houston), and coauthors confirm that thyroidectomy followed by RAI correlates with survival benefit in high risk but not low risk disease patients. Only moderate (not aggressive) THST was associated with improved survival, in all disease stages, and was predictive of improved disease-free survival for at least 3 years in patients identified as disease-free after initial therapy.

The poster presentation "Usefulness of Combined Therapy with 131I and Lithium in Patients with Metastatic Radioiodine-refractory Thyroid Cancer" describes a study by Ilhan Lim, M.D., Ph.D. and colleagues, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences (Seoul), of the therapeutic potential of lithium in combination with RAI in patients with metastatic DTC that has not responded to RAI treatment. Patients received oral lithium for 7 days, from 5 days before RAI therapy to 1 day after RAI. The researchers report a 45% response rate to the combined therapy after 6 months: 13/29 patients had stable disease and 16/29 patients had progressive disease. While the patients with stable disease at 6 months had better progression-free survival over time, they did not have better overall survival than the patients with progressive disease at 6 months. Compared to patients who received only conventional RAI, the patients who received combined treatment showed slightly higher 10-year survival rates than patients with conventional RAI (67.9% vs. 66.8%, p>0.05). Although it is not possible to compare the two groups equally, patients who received Li combined treatment survived longer (126.2 vs. 105.4 months) after propensity score matching.

SOURCE American Thyroid Association (ATA)