Objective   To explore the relationships between the expressions of thyroglobulin (Tg) measurement in fine-needle aspirates(FNA-Tg), thyroglobulin antibody measurement in fine-needle aspirates (FNA-TgAb) and lymph node metastasis in cervical area of papillary thyroid carcinoma under ultrasound guidance.

  Methods   Retrospective analysis was performed to collect the clinical data of 114 patients with papillary thyroid cancer accompanying with lymph node metastasis, among whom forty-one patients with lymph node metastasis confirmed by ultrasonography and surgical pathology were included in the metastatic group, and the remaining 73 patients were included in the non-metastatic group. Meanwhile, clinical data of 37 patients with papillary thyroid carcinoma without lymph node metastasis by ultrasonography and surgical pathology were collected and included in the negative control group. All patients included in the study were examined by ultrasound and ultrasound-guided detection of FNA-Tg and FNA-TgAb were performed. The expressions of FNA-Tg and FNA-TgAb under ultrasound guidance were compared, and receiver operator characteristic (ROC) curve was plotted. The value of ultrasound-guided detection of FNA-Tg or FNA-TgAb alone and their combined detection in predicting cervical lymph node metastasis in patients with papillary thyroid carcinoma were compared.

  Results   The levels of FNA-Tg and FNA-TgAb in the metastatic group were higher than those in the non-metastatic group and the negative control group, and their levels in the non-metastatic group were higher than those in the negative control group (P <0.05). FNA-Tg or FNA-TgAb detection alone and FNA-TG combined with FNA-TgAb detection in patients with papillary thyroid cancer were taken as test variables, while conditions of lymph node metastasis in the cervical region of patients with papillary thyroid cancer were taken as the status variables (1=lymph node metastasis, 0=non-metastasis), the ROC curve of the subjects was drawn. ROC curve results showed that values of the area under the curve(AUC) were both higher than 0.80 by FNA-Tg or FNA-TgAb detection alone and FNA-TG combined with FNA-TgAb detection in predicting cervical lymph node metastasis in patients with papillary thyroidcancer, and the predictive values were both satisfactory. The Cut-off values of FNA-Tg or FNA-TgAb detection alone were 115.959 ng/mL and 9.715 IU/mL, respectively based on the ROC curve.

  Conclusion   Ultrasound-guided FNA-Tg and FNA-TgAb expressions are closely related with lymph node metastasis in the cervical area in patients with papillary thyroid cancer, and the preoperative detection of FNA-Tg and FNA-TgAb levels under ultrasound guidance in patients with papillary thyroid cancer is considered to be a guidance for determining whether lymph node dissection is needed or not during radical thyroid cancer surgery.