Thyroglobulin measurement in fine-needle aspiration washout fluid for detection of differentiated thyroid cancer lymph nodes metastases

Abstract

Objective: To investigate the feasibiity of detecting lymph node metastasis in differentiated thyroid cancer patients by thyroglobin（Tg）measurement in fine-needle aspiration washout fluid. Method: Forty-seven differentiated thyroid cancer patients with cervical lymph node metastasis were included in this study. Fine-needle aspirations were performed on lymph nodes which were surgically resected for measurement of Tg in washout fluid. Diagnostic sensitivity, specificity and accuracy were evaluated according to three predetermined Tg threshold values: FNA-Tg/serum Tg＞1, 10 ng/ml and 100 ng/ml. Result: The meadian value of FNA-Tg in metastatic lymph node (n=46) was 5 177 ng/ml (1.79-408 300 ng/ml)，while lymph node without metastasis (n=11) showed a meadian level of 0.63 ng/ml (0.04-125.4 ng/ml). With the threshold of FNA-Tg level at FNA-Tg/serum Tg＞1, 10 ng/ml and 100 ng/ml respectively, the diagnostic sensitivity was 91.3%, 97.83% and 93.48% respectively,the specificity was 81.82%,63.64% and 90.90% respectively,and the accuracy was 89.47%,91.22% and 92.98% respectively. Conclusion: Thyroglobin measurement in fine-needle aspiration washout fluid is effective to diagnose lymph node metastasis in differentiated thyroid cancer.