Excellent diagnostic performance of FNA-Tg in detecting lymph nodes metastases from papillary thyroid cancer

Abstract

Background: Thyroglobulin washout of fine needle aspiration (FNA-Tg) has proved to be useful in detecting lymph node metastases from papillary thyroid cancer; however, the influences of thyroid gland, Hashimoto thyroiditis, serum thyroglobulin (Tg) and anti-TG antibody on the diagnostic performance of FNA-Tg are controversial. Patients & methods: We retrospectively collected the FNA-Tg results of 176 preoperative or postoperative patients (356 lymph nodes) who finally were diagnosed with papillary thyroid cancer. The diagnostic abilities of FNA-Tg were evaluated and compared under different circumstances. Results: The diagnostic performance of FNA-Tg was uninfluenced irrespective of the status of thyroid gland or serum anti-TG antibody. However, high serum Tg was positively correlated with FNA-Tg (Exp(B) = 1.57; 95% CI: 1.209–2.309; p = 0.001). Conclusion: FNA-Tg was an excellent diagnostic tool, but it should be interpreted with caution only if serum Tg is higher than 10 ng/ml.