Impact of Serum TSH and Anti-Thyroglobulin Antibody Levels on Lymph Node Fine-Needle Aspiration Thyroglobulin Measurements in Differentiated Thyroid Cancer Patients

Abstract

Background: Thyroglobulin measurements in the washout of fine needle aspiration (FNA-Tg) are an excellent tool to detect lymph node (LN) metastases of differentiated thyroid carcinoma (DTC). Nevertheless, how to define the best cutoffs and the influence of potential confounders are still being discussed. Objective: To evaluate the accuracy of FNA-Tg measurement to detect DTC metastases and the influence of thyroid status and anti-thyroglobulin antibodies (TgAb). Methods: One hundred thirty-eight patients with DTC and suspicious cervical LN were included. Patients underwent ultrasound (US)-guided FNA for cytological examination and FNA-Tg measurements. Final diagnoses were confirmed by histological examination or clinical and US follow-up for at least 1 year. Results: Data from 119 subjects with suspicious LN were evaluated. The median value of FNA-Tg in patients with metastatic LN (n = 65) was 3,263.0 ng/mL (838.55–12,507.5), while patients without LN metastasis (n = 54) showed levels of 0.2 ng/mL (0.2–0.2). According to the ROC curve analysis, the best cutoff value to predict metastasis was 4.41 ng/mL for FNA-Tg, with a sensitivity of 98% and specificity of 96%. There were no differences in the median of FNA-Tg measurements between those on (TSH 0.16 mUI/mL) and those off levothyroxine (TSH 99.41 mUI/mL) therapy (47.94 vs. 581.15 ng/mL, respectively; p = 0.79). Interestingly, the values of FNA-Tg in patients with LN metastasis (n = 65) did not differ between patients with positive and those with negative TgAb (88.8 vs. 3,263.0 ng/mL, respectively; p = 0.57). Conclusion: US-guided FNA-Tg proved to be a useful examination in the follow-up of patients with DTC, independently of TSH status and the presence of TgAb.

Clinical application of the ultrasound‐guided fine needle aspiration for thyroglobulin measurement to diagnose lymph node metastasis from differentiated thyroid carcinoma‐literature review

“…66,74 However, if lymph node aspirate is diluted over 50-fold, the Tg-Ab is nearly undetectable and cannot interfere with LN-FNA-Tg measurement even in the presence of sTg-Ab. 19,23,54,60 Based on meta-analysis and literature review, LN-FNA-Tg still maintains with excellent sensitivity and specificity for LNM even in presence of the sTg-Ab. Therefore, the ATA and ETA thyroid cancer treatment guidelines highly recommend using LN-FNA-Tg to diagnose LNM.…”

Clinical implications of anti-thyroglobulin antibody measurement before surgery in thyroid cancer

“…In multiple studies, however, high serum TgAb levels showed no interference with FNA-Tg sensitivity [ 52 , 53 ]. Duval et al [ 54 ] reported that the measurement of FNA-Tg is useful for evaluating suspicious lymph nodes in patients with DTC, regardless of TgAb. Boi et al [ 53 ] measured TgAb levels in FNA washout fluid in a limited number of patients, and found that TgAb was undetectable in patients with negative serum TgAb, but a small number of patients with positive serum TgAb (two of eight) showed positive TgAb in washout fluid.…”

Thyroglobulin measurement in fine-needle aspirates of lymph nodes in patients with differentiated thyroid cancer

“…типы карцином (недифференцированные раки щитовидной железы) с низкой экспрессией ТГ, определяемой степенью дифференцировки опухолевой ткани. Данный метод может быть особенно эффективен в случаях метастазов с кистозной дегенерацией или иных случаях малоинформативного цитологического заключения, кроме того, на результаты исследования не влияет уровень циркулирующих АТ-ТГ, что определяет его высокую диагностическую точность [25]. Поскольку на результаты исследования не влияет также наличие интактной тиреоидной ткани, он может быть использован в скрининге метастазов как у пациентов, повергшихся оперативному лечению, так и перед подготовкой к нему для установления стадии опухолевого процесса.…”