Role of preoperative washout fluid thyroglobulin from fine-needle aspirates in detecting lymph node metastases of papillary thyroid carcinoma and its influential factors / 中国肿瘤临床

ABSTRACT

Objective: To investigate the diagnostic value and influential factors of washout fluid thyroglobulin collected during fine-needle 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 cervi-cal lymph nodes and underwent high-frequency ultrasound-guided FNA before the surgery. FNA and FNA-Tg were performed simulta-neously. 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. Ad-ditionally, 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 diag-nostic performance of the combined method was the best when compared with other methods, with a sensitivity of 96.4% and speci-ficity of 99.2%. Additionally, FNA-Tg was much more accurate when used in diagnosis of lateral cervical lymph nodes. Among all the as-sociated 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, espe-cially 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.