Clinical and Morphological Characteristics as a Predictors of the Development of Radioiodine Resistance in Thyroid Cancer

Aim. To study the clinical and morphological risk factors for the development of radioiodine resistance in patients with highly differentiated thyroid cancer. Materials and methods. The study was conducted among patients treated at the radionuclide therapy department of the Centre for Nuclear Medicine and Oncology of the Abay Regional Health Department. For the analysis, a database of patients who underwent radioiodine therapy was created, which included 630 patients who underwent treatment for thyroid cancer between January 2021 and December 2023. Of these, 373 medical records met the established criteria for inclusion in the study. The statistical analysis was performed using the SPSS 20.0 program. Results and discussion. During the analysis of 373 patients, 60 were assigned to the main group with resistance to radioiodine therapy, and the remaining 313 were in the control group. When assessing the volume of surgery, total thyroidectomy with fascial-caseal excision of the neck tissue was performed for 58.3% of patients in the main group, characterized by resistance to radioiodine therapy, whereas in the control group, this volume of intervention was performed only in 29.1% (p<0.001). The main histological types of thyroid cancer in the study groups were papillary cancer (74.5%) and follicular cancer (25.5%). The presence of microcarcinoma against the background of these histological types of cancer was found in 8 patients of the control group. The presence of distant metastases was significantly more common in the main group (23.3% vs 7.3%) compared with the control (p<0.001). Conclusions. Based on the analysis, it can be concluded that, in particular, total thyroidectomy with lymph node dissection is statistically more often observed in patients with resistance to radioiodine therapy. However, surgical treatment itself is not a causal factor in the development of radioiodine resistance. Most likely, the expanded scope of surgery reflects a more aggressive course of the disease, which is initially associated with the risk of developing radioiodine-resistant forms of tumor. Histological examination data, detection of microcarcinoma, and the presence of distant metastases should be considered as clinical and morphological factors associated with the risk of developing resistance to radioiodine therapy in patients with highly differentiated thyroid cancer.