Studies On The Relationship Between Thyroglobulin Antibody And Malignant Degree Of Differentiated Thyroid Carcinoma And The Therapeutic Effect Of ¹³¹I

Purpose:Differentiated thyroid carcinoma?DTC?is the most common malignant tumor of the endocrine system,and its incidence is increasing rapidly in recent years.Thyroglobulin?Tg?is the major serum tumor marker in patients with DTC,which can monitor the recurrence or metastasis of tumors after treatment.High titer of thyroglobulin antibody?TgAb?will affect the accuracy of Tg determination and reduce the sensitivity of Tg as a tumor marker.In previous studies,it has suggested that TgAb can be used as a surrogate tumor marker for DTC.Current studies mostly focus on the role of TgAb in the diagnosis of DTC and whether the change trend of TgAb can predict the long-term recurrence or metastasis of tumors.However,there are few studies on the correlation between TgAb and the malignant degree of DTC and the therapeutic effect of ¹³¹I,and no unified conclusion has been reached.This study included two parts.The first part was to explore the correlation between positive preoperative TgAb and malignant degree of DTC.The second part was to explore the predictive effect of TgAb level after operation and the trend of TgAb change after ¹³¹I treatment on the curative effect of ¹³¹I treatment.Part 1Methods:95 TgAb-positive DTC patients admitted to the nuclear medicine department of tongji hospital from December 2016 to May 2018 were collected as the observation group,and171 TgAb-negative DTC patients admitted to our department during the same period were selected as the control group by simple random sampling method.A total of 266 cases were included according to inclusion and exclusion criteria.They were divided into two groups according to preoperative TgAb level.TgAb positive group?G1 group?and TgAb negative group?G2 group?.T-test,Kruskal-Wallis test and Chi-square test were used to compare preoperative serological parameters,pathological characteristics of tumors and BRAF mutations between G1 and G2 groups.Results:The proportion of female patients in G1 group was higher than that in G2 group??,and the average age was younger.The preoperative TSH,TgAb and TPOAb in G1 group were higher than those in G2 group,and the difference was statistically significant??.The number of patients with peripheral aggression in G1 group was lower than that in G2group??,but the number of multifocal tumors was more than that in G2 group??.The proportion of N₀ lymph node metastasis in G1group was lower than that in G2 group,and the proportion of N_1b was higher than that in G2 group??.The other pathological features?tumor size,bilateral and lymph node metastasis rate?had no significant difference?P>0.05?.The positive rate of BRAF mutations in group G1 was lower than that in group G2??.Conclusions:1.Preoperative TgAb positive was correlated with some pathological features of DTC.In multifocal and lymph node staging,TgAb positive patients were more malignant than TgAb negative patients,but less invaders were associated with peripheral involvement.2.BRAF gene mutation rate was lower in patients with positive preoperative TgAb.Part 2Methods:A retrospective analysis was made of 1210 patients with DTC who were treated in our department from December 2016 to May 2018.All patients underwent total thyroidectomy and ¹³¹I treatment,followed up regularly and evaluated the therapeutic efficacy.A total of95 DTC patients with positive TgAb were included according to inclusion and exclusion criteria.According to the imaging findings,the curative effect was divided into three groups:A?structural excellent response?,B?structural incomplete response?and C?structural indeterminate response?.Variance analysis,rank sum test?Kruskal-Wallis?,chi-square test and Fisher exact probability were used to analyze the factors that may affect the curative effect.After the analysis of the three groups,the groups with statistical significance have further compared in two or two to determine the source of the difference.Logistic multivariate regression analysis was used to analyze the factors with statistical significance.ROC curves were made with TgAb level before ¹³¹I treatment,percent change of TgAb 1.5months after treatment and percent change of TgAb for 3 to 6 months after treatment to determine the best critical value for predicting therapeutic effect.Results:The mean age?F=3.48,P=0.03?,lymph node metastasis rate??,TgAb level before ¹³¹I treatment??,¹³¹I dose??,1.5months,3-6 months and 6-12 months percent change and rate of change of TgAb were significantly different among the three groups.Statistically significant variables in the above univariate analysis were included in the multivariate logistic regression model.The results showed that the partial regression coefficients of TgAb level before ¹³¹I treatment?B=-0.006,P<0.001?,percent change of TgAb in 1.5 months?B=0.327,P=0.046?and percent change of TgAb in 3-6 months?B=2.521,P=0.041?had statistical significance,while age?B=0.078,P=0.088?,lymph node metastasis rate?B=0.078,P=0.088?and percent change of TgAb in 6-12 months?B=-2.140,P=0.140?had no statistical significance.The best threshold value of TgAb level on ROC curve was 201.4 U/mL.The sensitivity,specificity,positive and negative predictive values were 74.1%,68.3%,75.5%and 66.7%respectively.The area under ROC curve?AUC?was 0.740?0.545⁰.775,P<0.05?.The best critical value of percent change of TgAb in 1.5 months after treatment was9.7%.The corresponding sensitivity,specificity,positive predictive value and negative predictive value were 72.2%,61.0%,70.9%and 62.5%respectively.The AUC was 0.660?0.545⁰.775,P<0.05?.The optimal critical value of percent change of TgAb for 3 to 6months after treatment was 19.2%.The corresponding sensitivity,specificity,positive predictive value and negative predictive value were 80.7%,58.5%,73.4%and 77.4%respectively.The AUC was 0.752?0.651⁰.853,P<0.05?.Conclusions:1.Postoperative TgAb level enabled to predict the therapeutic effect of ¹³¹I.Those with lower TgAb level had better therapeutic effect,and the optimal threshold value was201.4 U/mL.2.The decrease of TgAb after treatment was more significant,suggesting that the patients may have a better ¹³¹I therapeutic effect.