Retrospective evaluation of factors determining refractory in iodine refractory thyroid carcinoma

Introduction: Considering that iodine refractoriness may be related to disorders that may occur in the NIS (Sodium Iodine Symport) responsible for iodine intake, we aimed to evaluate the clinical and pathological characteristics of patients diagnosed with iodine refractory thyroid carcinoma admitted to our clinic and the gene expression encoding the SLC5A5 NIS membrane protein. Material-Method: In this study, 01/01/2013-15/09/2021 between dates University of Gaziantep, Department of Internal Medicine, Clinic of Endocrinology and Metabolism Department of Iodine refractory thyroid carcinoma and 32 patients with refractory non of 51 patients with biochemical parameters and histopathological types and FDG-PET/CT, CT, MRI, USG imaging evaluation of the NIS protein SLC5A5 gene was examined. 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 and The median of the patient group was 55 (46.5 -70), while the median of the control group was 48 (38 -55). While the median±SD value of baseline Tg was 3588.11 ± 8975.48 in the patient group, it was 310.46 ± 1796.86 in the control group. The median value of the patient group was 278 (65-724 ), while it was 3.21 (0.66 -23.7). The mean age of 13 patients with refractory thyroid carcinoma who received chemotherapy was 65.77 (standard deviation: 12.58), The mean age of 19 patients who did not receive chemotherapy was 50.26 (standard deviation: 13.80). The mean age of those who did not receive treatment is lower than those in the patient group. All these parameters and statistically significant (p<0,05). SLC5A5 gene expression decreased in the iodine non-refractory PTK group and increased in the iodine refractory PTK group. Conclusion: Advanced age (age > 55 years) and high post operative thyroglobulin level (278 ng/ml) are effective in the development of iodine refractoriness 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. SLC5A5 gene expression was increased in radioactive iodine refractory thyroid carcinoma compared to benign tissues, but decreased in radioactive iodine sensitivity. Contrast expression changes in SLC5A5 gene expression may be a guide to better understand the pathophysiological mechanism of RAI refractory disease. Key words: Iodine Refractory Thyroid Carcinoma, NIS (Sodium Iodine Symport), SLC5A5.