Preparation for radioiodine therapy in patients with differentiated thyroid cancer, modern perspective. Review of the literature.

Thyroid cancer is the most common tumor of the endocrine system, 1-3% of all malignant neoplasms as of 2021. Differentiated forms, papillary and follicular, with a relatively favorable prognosis, are detected in 90% of cases. In recent years, therapy for well-differentiated thyroid cancer (WDTC) has not significantly changed and includes surgical treatment, hormone therapy, radioiodine therapy when indicated, and dynamic monitoring with possible expansion to advanced therapeutic options in cases of disease recurrence. However, there are a range of unresolved issues that are continuing to be actively investigated by new laboratory and instrumental methods. Particularly, one of these issues is the preparation in patients with differentiated thyroid cancer for radioiodine therapy. Radioiodine therapy (RIT) is considered as one of the first targeted therapies for thyroid cancer with a history of over 80 years of use, the main purpose of which is ablation of residual thyroid tissue as well as therapy of distant and/or regional metastases of thyroid cancer. The combination of surgical treatment and subsequent radioiodine therapy provides a favorable prognosis in patients with WDTC, but there is a remaining possibility of insufficient response to radioiodine therapy, which may be associated with multiple factors, including the phase of preparation for RIT. The publication provides a review of the scientific literature on the aspects of preparation of patients with WDTC for radioiodine therapy. The principles of preparation are based on the recommendations of the leading expert societies and studies published in the world practice, as well as known side effects during preparation for radioiodine therapy and thereafter, their impact on patients' quality of life, effectiveness and long-term results of treatment. Materials and Methods Scientific articles and reviews from Medline, Cochrane, and Google Scholar databases were searched by keywords, and recommendations regarding WDTC of the scientific societies were used. Articles in Russian and English with full-text availability were selected; those published after January 2023 were excluded. A systematic evaluation of 130 sources was performed, general trends in the modern approach to patient preparation for radioiodine therapy and current problems were highlighted, and results and conclusions were formulated