Latest Research on Thyroid Cancer Therapy Presented at American Thyroid Association Annual Meeting

October 28, 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.

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The American Thyroid Association (ATA) is the leading worldwide organization dedicated to the advancement, understanding, prevention, diagnosis, and treatment of thyroid disorders and thyroid cancer. ATA is an international membership medical society with over 1,700 members from 43 countries around the world. Celebrating its 91st anniversary, the ATA delivers its mission — of being devoted to thyroid biology and to the prevention and treatment of thyroid disease through excellence in research, clinical care, education, and public health — through several key endeavors: the publication of highly regarded professional journals, Thyroid, Clinical Thyroidology, and VideoEndocrinology; annual scientific meetings; biennial clinical and research symposia; research grant programs for young investigators, support of online professional, public and patient educational programs; and the development of guidelines for clinical management of thyroid disease and thyroid cancer. The ATA promotes thyroid awareness and information through its online Clinical Thyroidology for the Public (distributed free of charge to over 11,000 patients and public subscribers) and extensive, authoritative explanations of thyroid disease and thyroid cancer in both English and Spanish. The ATA website serves as the clinical resource for patients and the public who look for reliable information on the Internet.