Optimal method for detecting cervical lymph node metastasis from papillary thyroid cancer

Purpose Papillary thyroid cancer (PTC) is often accompanied by cervical lymph node metastases (LNM). This study compared the diagnostic performance of fine needle aspiration (FNA), the combination of FNA and thyroglobulin measurement in the washout (FNA-Tg), and core needle biopsy(CNB) in order to determine the optimal method in detecting cervical LNM from PTC. Methods PTC patients with suspicious cervical lymph nodes, who underwent ultrasonography-guided FNA, or CNB before surgery were retrospectively reviewed between January 2021 and April 2022. Patients' demographics, lymph node size, and results of FNA, FNA-Tg, CNB and surgical pathology were collected. Sensitivitity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy and the area under the curves (AUC) of receiver operating characteristic were obtained. Results FNA-Tg had a higher AUC with a threshold of 55 ng/mL than that with a threshold of 1 ng/mL (0.782 vs. 0.636, P = 0.005). The sensitivity of the combination of FNA and FNA-Tg was higher than that of FNA alone (91.3% vs. 81.0%, P = 0.01), but it was not different from that of CNB (91.3% vs. 88.0%, P > 0.05). No significant difference was found in specificity, PPV, NPV, accuracy and AUC among FNA alone, CNB alone, and the combination of FNA and FNA-Tg. Conclusions FNA-Tg is useful to improve the sensitivity of FNA. The diagnostic performance of the combination of FNA and FNA-Tg is better than that of FNA or FNA-Tg alone, but is not different from that of CNB in detecting LNM from PTC.