The Role Of Thyroglobulin In Predicting Lateral Cervical Lymph Node Metastasis Of Thyroid Papillary Carcinoma

ObjectivePapillary thyroid carcinoma（PTC）is the most common differentiated thyroid carcinoma.Although the disease progresses slowly and has a good prognosis in most patients,there are still some patients with malignant tumor progression such as extra-glandular invasion,lymph node metastasis and tumor recurrence.Among them,Lateral cervical lymph node metastasis is the most important risk factor for increased tumor recurrence rate and decreased survival rate in patients with papillary thyroid carcinoma.Therefore,early diagnosis and timely treatment of lateral cervical lymph node metastasis are very important for patients with papillary thyroid carcinoma.At present,the preoperative diagnosis of lateral cervical lymph node metastasis mainly relies on preoperative ultrasound and puncture pathology,but both methods have certain limitations.So we still need to look for other ways to complement existing methods.Thyroglobulin（Tg）is the most important component of follicular colloid and cell matrix in thyroid tissue,and its application value in the diagnosis and treatment of thyroid papillary carcinoma has been fully affirmed.For example,Tg in puncture fluid and serum Tg after total thyroidectomy can be used for the diagnosis and recurrence monitoring of papillary thyroid carcinoma^[1].In recent years,studies have found that preoperative serum Tg has certain value in predicting lateral cervical lymph node metastasis of differentiated thyroid cancer^[2,3],but its effect needs to be further studied.This study intends to make full use of the clinical database of thyroid cancer in our hospital to analyze the significance and value of serum thyroglobulin in the preoperative prediction of lateral cervical lymph node metastasis of thyroid papillary carcinoma.Methods1.After rigorous screening,1310 patients with PTC who underwent surgical treatment in the thyroid surgery department of the First Hospital of Jilin University from January 1,2019 to January 1,2020,were selected as the study subjects.2.Organize the collected case information,including basic case information,preoperative serum Tg level,cervical Doppler ultrasonography description and postoperative paraffin pathological section results（including unilateral/bilateral tumor distribution,multifocal,maximum tumor diameter,total tumor diameter,lymph node metastasis,etc.）.3.1310 patients were divided into three groups according to different degree of cervical lymph node metastasis in pathological results.781 patients without cervical lymph node metastasis were in the N0 group.A total of 434 patients with central lymph node metastasis alone,referred to as N1a group;A total of 95patients in the central region with lateral cervical lymph node metastasis were referred to as group N1b.In the separate study of the predictive effect of Tg on lateral cervical lymph node metastasis,the cases of N0 group and N1a group were combined,which were collectively referred to as non-lateral cervical lymph node metastasis group,or Non-N1b group for short.4.The differences between the clinicopathological characteristics and the preoperative serum thyroglobulin level between each group were analyzed,and the practical value and significance of the preoperative serum thyroglobulin level detection for the evaluation of lateral cervical lymph node metastasis in patients with papillary thyroid carcinoma were evaluated.5.SPSS26.0 was used for statistical analysis of the collected data.P<0.05 was considered statistically significant.ResultsIn this study,it was found that,among the observed clinical factors that may affect cervical lymph node metastasis,there were significant differences in preoperative serum Tg levels between the N0 and N1a groups and between the N1a and N1b groups,while there was no statistically significant difference between the N0 and N1a groups（P=0.051）;Among the other influencing factors,gender,age and tumor bilaterality only had significant differences between the N0 and N1a groups and the N0 and N1b groups,but had no significant differences between the N1a and N1b groups（P>0.0167）;There were significant differences between N0 and N1a,N0 and N1b,N1a and N1b groups among patients with different maximum tumor diameter,total tumor diameter,and bilateral tumor presence（P<0.0167）.Preoperative serum Tg concentration of>20ng/m L（OR=4.539,95%C.I.2.659-7.748）was an independent risk factor for PTC lateral cervical lymph node metastasis.Other risk factors for PTC lateral cervical lymph node metastasis included male（OR=2.093,95%C.I.）,age<55years old（OR=3.802,95%C.I.1.705-8.482）,multifocal（OR=2.059,95%C.I.1.281-3.310）and the maximum tumor diameter>1cm（OR=9.471,95%C.I.5.711-7.748）.Preoperative serum Tg concentration has a certain reference value for predicting central lymph node metastasis,and it has a higher diagnostic value for lateral cervical lymph node metastasis.When the concentration of19.77ng/m L was selected as the cut-off value,the specificity and sensitivity of preoperative serum Tg in the diagnosis of lateral cervical lymph node metastasis were 68.2%and 76.8%.When the cut-off value was set at 99.87ng/m L,the specificity and sensitivity of preoperative serum TG in the diagnosis of lateral cervical lymph node metastasis was 95.1%and 16.8%.Preoperative serum TG concentration increased with the increase of the number of lateral cervical metastatic lymph nodes.At the same time,the maximum tumor diameter was significantly correlated with the preoperative serum TG concentration（β=40.702,P=0.000）.The larger the maximum tumor diameter was,the more likely the Tg value was to increase.Conclusions1.Preoperative serum Tg level>20ng/m L is an independent risk factor for lateral cervical lymph node metastasis in PTC patients,which can provide useful information for preoperative prediction of lateral cervical lymph node metastasis in PTC patients.2.When the preoperative serum TG concentration>100ng/m L,the probability of lateral cervical lymph node metastasis in PTC patients increased significantly.3.Preoperative elevated serum Tg level was positively correlated with the number of lateral cervical lymph node metastasis in patients with papillary thyroid carcinoma.Preoperative serum Tg level detection can help to predict the severity of lateral cervical lymph node metastasis in patients with papillary thyroid carcinoma to a certain extent.4.Preoperative serum Tg level was positively correlated with the maximum tumor diameter in patients with papillary thyroid cancer,and the detection of preoperative serum Tg level was of certain value in helping to judge tumor growth activity in patients with papillary thyroid cancer.