Combining Thyroglobulin Levels in Lymph Node Wash-out Fluid with TI-RADS to Predict Lymph Node Metastasis in Papillary Thyroid Carcinoma.

Objective: This study was aimed at investigating if the lymph node aspirated wash-out liquid thyroglobulin level and thyroid imaging reporting and data system (TI-RADS) nodule score can be the predictive factor for cervical lymph node metastasis in patients with papillary thyroid carcinoma (PTC).

Methods: The study included 251 patients with surgically confirmed PTC. All the patients underwent preoperative thyroid and cervical ultrasound examination using ACR TI-RADS classification, fine-needle aspiration biopsy (FNAB) for BRAF V600E gene detection, and thyroglobulin (Tg) detection in lymph node aspiration fluid. The results of these examinations and tests were statistically analyzed. A binary logistic regression model was used to determine the predictive impact of Tg levels, gene mutation status, and TI-RADS nodule score on lymph node metastasis.

Results: Among the enrolled patients, 219/251 (87.25%), had BRAF V600E gene mutations and 132/251 (52.59%) had cervical lymph node metastasis. The Tg level in the lymph node aspiration fluid of patients with metastasis was significantly higher than in those without metastasis (324.94 ± 192.52 ng/mL vs 67.93 ± 136.62 ng/mL, P = 0.000), but there was no significant difference in serum Tg levels between the two groups (27.08 ± 71.60 ng/mL vs 20.73 ± 55.21 ng/mL, P = 0.276). The area under the ROC curve (AUC) for lymph node aspiration fluid Tg was 0.858. Thyroglobulin level has a significant positive effect on lymph node metastasis, with a regression coefficient of 0.003 and P = 0.000 < 0.001. BARF V600E mutation status and TI-RADS nodule score do not have a significant effect on lymph node metastasis, with P-values greater than 0.05.

Conclusion: Thyroglobulin levels of lymph node aspiration fluid has a good predictive value for the diagnosis of cervical lymph node metastasis in PTC patients with larger nodules.