Abstract:
Objective :To investigate the diagnostic value and influential factors of washout fluid thyroglobulin collected during fineneedle aspiration (FNA-Tg) in detecting lymph node metastases of papillary thyroid carcinoma (PTC) before thyroidectomy.
Methods : We retrospectively analyzed 131 patients diagnosed with PTC based on histopathology.They presented with suspicious enlarged cervical lymph nodes and underwent high-frequency ultrasound-guided FNA before the surgery.FNA and FNA-Tg were performed simultaneously.All the related data were collected.In order to obtain the best cut-off value, the FNA-Tg receiver-operating characteristic curve was generated.The cytopathology and postoperative pathologic
Results , as well as the ultrasound images during the follow-up, were considered the gold standard.The diagnostic performance of each method (FNA, FNA-Tg, and FNA+FNA-Tg) were compared.Additionally, some suspicious influential factors such as the anatomical location of lymph nodes and associated laboratory indexes were also analyzed for the diagnostic accuracy of FNA-Tg.Results:The best cut-off value of FNA-Tg in our study was 1.295 ng/mL.The diagnostic performance of the combined method was the best when compared with other Methods, with a sensitivity of 96.4% and specificity of 99.2%.Additionally, FNA-Tg was much more accurate when used in diagnosis of lateral cervical lymph nodes.Among all the associated laboratory indexes, the level of serum Tg (sTg) was an independent predictive factor for an FNA-Tg level above 1.295 ng/mL (odds ratio=1.018).
Conclusions :FNA-Tg is a useful tool in the identification of metastatic cervical lymph nodes preoperatively, especially for lateral cervical lymph nodes.In addition, 1.295 ng/mL could be one of the reference standards of the FNA-Tg cut-off value. When the sTg level is high, we should interpret the FNA-Tg Results cautiously