ABSTRACT
Objective: To investigate the value of ultrasound-guided fine-needle aspiration (FNA) biopsy combined with thyroglobulin in fine-needle aspirate fluid (FNA-Tg) measurement in diagnosis of preoperative lateral neck lymph node (LN) metastasis of papillary thyroid carcinoma (PTC). Methods: Totally 111 preoperative PTC patients diagnosed with FNA with suspected metastatic LNs were collected and then underwent neck ultrasonography together with FNA cytclogy. FNA-Tg was measured, then the eluents were obtained by flushing aspiration needle with 1 ml normal saline. FNA-Tg of elution was measured by electrochemiluminescence immunoassay. Taken postoperative pathologic results as the gold standards, ROC curve was drawn, the optimal threshold value for diagnosis of FNA-Tg, the diagnostic efficiency of FNA, FNA-Tg, combined FNA and FNA-Tg for suspected metastatic LNs were evaluated. Results: Among 118 suspicious LNs, 81 (81/118, 68.64%) LNs of metastasis and 37 (37/118, 31.36%) LNs without metastasis were confirmed by postoperative pathology. The average value of FNA-Tg in metastasis LNs was significantly higher than that of LNs without metastasis (P<0.001). The optimal diagnostic value of FNA-Tg in diagnosis of LNs metastasis was 2.65 μg/L, and the AUC was 0.937 (95%CI [0.894, 0.980], P<0.001). The differences of accuracy, sensitivity and negative predictive value were all statistically significant between FNA-Tg and FNA (all P<0.05). The accuracy, sensitivity and negative predictive value of FNA combined with FNA-Tg were higher than that of only FNA (all P<0.05). Twenty-two FNA false-negative nodes were correctly diagnosed with FNA-Tg testing. Conclusion: FNA cytology and FNA-Tg detection are useful ancillary tests that can improve the detection of lateral neck LN metastasis of PTC. Combination of FNA and FNA-Tg can significantly increase the accuracy and sensitivity of preoperative diagnosis of lateral neck LN metastasis of PTC, and may have an important role in surgical planning of PTC patients.