The Value Of FNA-TG And FNAB In The Evaluation Of Cervical Lymph Node Metastasis In Patients With PTC After Successful Ablation

Objective: To evaluate the value of ultrasound-guided thyroglobulin in fine-needle aspirate fluid(FNA-TG)and fine-needle aspiration biopsy(FNAB)in evaluating cervical lymph node metastasis in patients with PTC after successful iodine-131 ablation.Methods: A total of 94 patients with PTC who underwent ultrasound examination in our hospital from November 2017 to December 2020 and found suspicious metastatic lymph nodes in the neck(lymph node enlargement or accompanied by malignant ultrasound signs)were collected.All patients of the group completed iodine-131 ablation successfully,and the cervical lymph nodes were examined by FNA-TG and FNAB.The 106 lymph nodes examined by puncture were divided into group A(short diameter ≤ 5 mm,67 lymph nodes),group B(short diameter > 5 mm,39 lymph nodes),metastatic group(91 lymph nodes)and non-metastatic group(15 lymph nodes),and ROC curve was used to calculate the optimal diagnostic threshold of FNA-TG,and to analyze and compare the diagnostic efficacy of FNA-TG,FNAB and the combination of the two methods.Results:(1)The lymph nodes in the metastatic group were mostly distributed in the neck area III,IV and VI,and the difference was statistically significant compared with the non-metastatic group(P<0.05).(2)Lymph node FNA-TG levels and serum TG levels in group B were higher than those in group A(P<0.05);lymph node FNA-TG levels and serum TG levels in the metastatic group were significantly higher than those in the non-metastatic group(P<0.05).(3)The serum TG level was positively correlated with the lymph node FNA-TG level(ρ=0.667,P<0.001).(4)The optimal threshold of FNA-TG to diagnose PTC cervical lymph node metastasis was 1.16ng/m L in this study.(5)The accuracy of FNA-TG in diagnosing lymph node metastasis in group A was significantly higher than that of FNAB(P<0.05);there was no significant difference in the accuracy of FNA-TG and FNAB in diagnosing lymph node metastasis in group B(P>0.05).The sensitivity,accuracy and predictive value of negative results of FNA-TG in the diagnosis of PTC cervical lymph node metastasis were higher than those of FNAB(P<0.05);the combined method of FNA-TG and FNAB had higher sensitivity,specificity and accuracy in the diagnosis of PTC cervical lymph node metastasis.Conclusions: Ultrasound-guided FNA-TG has high value in evaluating cervical lymph node metastasis in patients with PTC after successful ablation,and can be used as a supplementary diagnosis for FNAB,especially for PTC metastatic lymph nodes with short diameter ≤5mm.It is suggested that the use of FNA-TG combined with FNAB examination can improve the diagnostic efficacy of PTC cervical lymph node metastasis.FNA-TG 1.16ng/ml can be used as a reference threshold concentration in diagnosis.