Association between Thyroid Profile Levels and Lymph Node Metastasis in Papillary Thyroid Carcinoma: A Retrospective Study

<b>Background:</b> Thyroid cancer is the most common endocrine carcinoma, accounting for 3.26% of all cancers. The most histologically, well-differentiated thyroid cancer is papillary thyroid carcinoma (PTC). Although PTC is regarded as an indolent tumor, a portion of the cancer cells metastasize to lymph nodes around the thyroid gland. Lymph node metastasis (LNM) is a critical risk factor for tumor recurrence in PTC, which strongly affects disease prognosis and the quality of life. <b>Methods:</b> This study aims to examine how differences in the level of the thyroid profile and other risk factors may influence LNM incidence in patients with PTC in Taiwan. We carried out a single-center retrospective study. These PTC patients were retrospectively reviewed by the Department of Endocrinology from 2016 to 2019. A total of 165 patients were included in our research. <b>Results:</b> The findings revealed a close relationship with the level of free thyroxine (FT4), the level of the thyroid-stimulating hormone (TSH), and lymph node metastases. The correlation in terms of FT4 (<i>p</i> = 0.005) and TSH (<i>p</i> = 0.417) with LNM was found as a result of the univariate regression analysis. In the multiple regression analysis, the findings revealed a close relationship between LNM, FT4 (<i>p</i> < 0.001), and TSH (<i>p</i> = 0.008). <b>Conclusions:</b> Although the predictability of the TSH should be examined further, the association between LNM and FT4 or TSH should not be ignored. The results could help guide decision-making and patient counseling, using the level of serum FT4 or the TSH as a possible predictive factor of the LNM in PTC.