Endocrine Abstracts

Introduction: Radioiodine-resistant thyroid carcinoma is an important milestone in the treatment and follow-up of thyroid cancers. The biological defects of iodine uptake in thyroid cancer cells should be well known. In this study, we aimed to evaluate the clinical and pathological features and SLC5A5 gene expression status of iodine-refractory papillary thyroid carcinoma patients.

Material-Method: We studied SLC5A5 expression in 83 papillary thyroid carcinoma patients before radioactive iodine treatment was given. While 32 of these patients were radioactive iodine-refractory, 51 of them were cured with radioactive iodine on the follow-up. Biochemical, histopathological, and radiological data were gathered retrospectively.

Results: While the median±SD age in the iodine-refractory thyroid carcinoma group was 56.56 ± 15.22, it was 46.82 ± 12.43 in the control group. The median value of the refractory patient’s thyroglobulin was 278 (65-724), while it was 3.21 in the non refractory group (0.66–23.7). The mean age of 13 patients with refractory thyroid carcinoma who received chemotherapy was 65.77±12.58. The mean age of 19 patients who did not receive chemotherapy was 50.26±13.80. SLC5A5 gene expression increased in the iodine non-refractory PTK group and decreased in the iodine refractory PTK group. All these parameters and statistically significant (P<0.05).

Conclusion: Advanced age (age > 55 years) and a high postoperative thyroglobulin level (278 ng/ml) are effective in the development of iodine resistance in patients with differentiated thyroid carcinoma. In addition, the presence of advanced age in patients with iodine-refractory thyroid carcinoma is associated with the need for chemotherapy. Contrast expression changes in SLC5A5 gene expression may be a guide to better understand the pathophysiological mechanism of RAI refractory disease.