Application of thyroglobulin measurement in fine-needle aspiration for detecting lymph node metastasis in papillary thyroid carcinoma

Objective To explore the diagnostic value of thyroglobulin measurement with fine-needle aspiration (FNA-Tg) in detecting papillary thyroid carcinoma(PTC) metastatic lymph nodes, and analyze the impact of different factors on the diagnostic accuracy of FNA-Tg. Methods One hundred and fifty-four lymph nodes from 138 patients who underwent total thyroidectomy and cervical lymphadenectomy were enrolled. Ultrasonography, fine needle aspiration cytology (FNAC) and FNA-Tg results were acquired in all patients. The diagnostic value of FNAC, FNA-Tg and the combination of the two methods were compared in suspicious PTC metastatic lymph nodes. The influence of lymph nodes size, lymph nodes cystic change and serum thyroglobulin antibody(TgAb) on the accuracy of FNAC and FNA-Tg were analyzed. Results The sensitivities of FNAC, FNA-Tg, and the combination of the two methods in the diagnosis were 79.5%, 95.5% and 97.7%, respectively. The specificities were 100%, 93.9% and 100%, respectively. The size and cystic change of lymph nodes had effects on the accuracy of FNAC(P<0.05), while they had no effect on the accuracy of FNA-Tg (P=0.42, 0.67). The serum TgAb level had no influence on the accuracy of FNAC and FNA-Tg (P=0.88, 0.34). Conclusions FNA-Tg is sensitive to metastatic lymph nodes in PTC which not affected by the lymph nodes size, the lymph nodes cystic change and serum TgAb level. Application of FNA-Tg with FNAC can improve the sensitivity of diagnosis, which is important in the diagnosis of PTC metastatic lymph nodes. Key words: Ultrasonography; Fine-needle aspiration cytology; Papillary thyroid carcinoma; Thyroglobulin; Lymph node metastasis