Diagnostic value of ultrasound-guided fine-needle aspiration cytology and thyroglobulin detection in aspiration washout fluid for neck lymph nodes metastasis in patients with papillary thyroid carcinoma

Objective To investigate the diagnostic value of ultrasound-guided fine-needle aspiration cytology (FNAC) and fine-needle aspiration washout fluid thyroglobulin (FNA-Tg) detection for neck lymph nodes metastasis in patients with papillary thyroid carcinoma (PTC). Methods A total of 214 PTC patients confirmed by pathology biopsy in Baoji Central Hospital from August 2015 to October 2018 were collected, and they all underwent ultrasound-guided FNAC, and FNA-Tg was measured by using electrochemiluminescence immunoassay. The histopathologic detection was performed for all suspicious lymph nodes after lymphadenectomy, and the results were analyzed by using statistics. Results There were 282 suspicious enlarged lymph nodes detected from 214 PTC patients. Histopathological examination showed 220 lymph node metastases were positive, 62 were negative. FNAC examination showed 193 lymph nodes were positive and 89 were negative. The sensitivity, specificity, Youden index, positive predictive value, negative predictive value, accuracy of FNAC for diagnosing the lymph nodes of metastasis PTC was 84.55%, 88.71%, 73.26%, 96.37%, 61.80%, 85.46%, respectively. FNA-Tg test showed that 198 lymph nodes were diagnosed as positive metastasis and 84 were negative metastasis. The sensitivity, specificity, Youden index, positive predictive value, negative predictive value, accuracy of FNA-Tg for diagnosing the lymph nodes of metastasis PTC was 88.64%, 95.16%, 83.80%, 98.48%, 70.24%, 90.07%, respectively. Both FNAC and FNA-Tg test showed 215 lymph nodes were diagnosed as positive metastasis and 76 were negative metastasis. The sensitivity, specificity, Youden index, positive predictive value, negative predictive value, accuracy of combined treatments were 97.63%, 87.32%, 84.95%, 95.81%, 92.54%, 96.81%, respectively. The sensitivity and accuracy of combined detection were higher than those of single detection, and there were statistically significant differences (all P < 0.05). Conclusions FNAC and FNA-Tg detection are simple, safe and accurate. The combined detection of FNAC and FNA-Tg can improve the sensitivity and accuracy for the diagnosis of PTC lymph node metastasis. Key words: Thyroid neoplasms; Carcinoma, papillary; Lymph nodes metastasis; Biopsy, fine-needle; Washout fluid; Thyroglobulin