A nomogram model for early lymph node metastasis of differentiated thyroid carcinoma on basis of thyroglobulin and antibody quantification

  Objective  To investigate the relationships between the quantification of thyroglobulin(Tg), quantitative antibody and early lymph node metastasis in differentiated thyroid carcinoma (DTC), and construct a quantitative nomogram model.

  Methods  A total of 86 patients who underwent radical thyroidectomy were chosen as research objects, 113 lymph nodes with suspicious metastases in the neck area were detected by ultrasonography before operation, including 74 positive(57 patients, positive lymph node group) nodes and 39 negative(29 patients, negative lymph node group) nodes confirmed by pathology after operation. The ultrasonic quantitative score of lymph nodes, fine needle aspiration cytology (FNA-C), fine needle aspiration thyroglobulin (FNA-Tg) and BRAF gene mutation in puncture needle eluent, serum Tg, thyroglobulin antibody (TgAb) and thyroid hormones were compared.

  Results  There were no differences of gender, age, tumor stage, differentiation grade and pathological type, quantitative ultrasound score, positive rate of BRAF gene mutation, serum Tg and thyroid hormone levels (P>0.05). FNA-C positive rate, FNA-Tg and serum TgAb levels in the positive lymph node group were significantly higher than those in the negative lymph node group (P < 0.05). Multivariate Logistic regression analysis showed that positive for FNA-C, FNA-Tg≥25 μg/L and serum TgAb≥500 U/mL were predictors of positive lymph node metastasis (P < 0.05). Receiver operating curve showed that the area under the curve of ultrasound quantitative score, FNA-C, FNA-Tg and nomogram model for predicting positive lymph node metastasis were 0.689, 0.754, 0.795 and 0.856, respectively (P < 0.05).

  Conclusion  FNA-C and FNA-Tg are important basis in diagnosing DTC lymph node metastasis before operation. The nomogram model constructed by large sample data has good predictive efficiency for positive lymph node metastasis. The nomogram model can help doctors accurately and quickly judge metastatic lymph nodes before operation, and overcome the diagnosis deficiency of FNA-C or FNA-Tg alone, and has strong practicability.