The localization of thyroid cancers on the thyroid gland is a new risk factor for metastases of perithyroidal, peritracheal and central lymph nodes

Abstract

Lymph node metastasis is frequently detected in differentiated thyroid cancers. Central dissection is performed to the lymph nodes in patients with microscopic metastases in the intraoperative evaluation. Other indications for central dissections are tumor size and cervical lateral lymph node metastasis. We consider that the localization of thyroid cancer in the thyroid lodge may be another risk factor for central lymph node metastasis. For this reason, the purpose of the present study was to investigate the relations between thyroid cancer localization and lymph node metastasis in differentiated thyroid cancer patients who had no preoperative cervical metastases and who underwent total thyroidectomy, and peritracheal, perithyroidal, and central lymph node dissection. A total of 213 differentiated thyroid cancer cases followed in our general surgery and endocrinology clinic between September 2016 and May 2020 were evaluated retrospectively. Based on the data in the files, the patients who underwent total thyroidectomy, and central, perithyroidal, and peritracheal lymph node dissection were included in the study. The patients were divided into four Groups according to tumor localizations, those with tumors adjacent to the trachea (Group 1), upper thyroid pole (Group 2), thyroid middle part (Group 3), thyroid inferior (Group 4). The demographic characteristics, laboratory parameters, cancer types, and lymph node metastasis rates of the Groups were evaluated. A total of 84% (179) of the cases had thyroid papillary cancer, 11.73% (25) had thyroid follicular cancer, and 4.2% (9) had poorly differentiated thyroid cancer. The mean age of all patients was found to be 49 ± 8.3years, and the female/male ratio was 2.4. It was found that the differentiated thyroid cancers metastasized to the perithyroidal, peritracheal, and central lymph nodes at a rate of 57.74%. The distribution of these metastases according to the Groups was; 62.85% in Group 1, 11.53% in Group 2, 43.9% in Group 3, and 88.57% in Group 4. It was also found that 80.32% of the papillary cancer cases and 57.14% of the follicular cancer cases metastasized to central (level VI) lymph nodes in Group 4. The localization of differentiated thyroid cancers is a new risk factor for perithyroidal metastases.