The Preliminary Clinical Study Of The Relationship Of Preablative Stimulated Thyroglobulin Level And With The Response Of Radioiodine Treatment In Non-distant-metastatic DTC Patients

Objective: To evaluate the feasibility of preablative stimulated thyroglobulin(ps-Tg)predicting therapeutic response in non-distant-metastatic differentiated thyroid cancer patients.Methods:In this study,303 non-distant-metastatic differentiated thyroid cancer(DTC)patients who had received radioactive iodine(RAI)therapy between January 2013 to December 2015 for the first time in the First Hospital of China Medical University were adopted.All of those patients had undergone total/near total/subtotal thyroidectomy before RAI and were followed for a median of 22.62 months after RAI.The clinical outcome of each patient was evaluated,based on the response to therapy restaging system proposed by American Thyroid Association in 2015.The DTC patients were divided into 4 groups according to their clinical outcomes: Excellent Response group(ER,n=166),In-Determinate Response group(IDR,n=78),Biochemical Incomplete Response group(BIR,n=47),Structural Incomplete Response group(SIR,n=12).The Kruskal-Wallis test was used to evaluate the clinicopathologic features among 4 groups.The ROC curve and optimal cut-off point were employed to evaluate the predictive value of ps-Tg level and ps-Tg /TSH ratio for ER group and SIR group.These patients were as well divided into three groups in terms of ps-Tg level: group 1(n=79),less than 1 ng/m L;group 2(n=123),1–10ng/m L;and group 3(n=101),more than 10 ng/m L.The composition ratio of group 1,group 2 and group 3 was compared with each other by chi-square/Fisher exact test.Results:There was no significant difference in sex(H=3.73,P=0.21),age(H=5.85,P=0.12),TNM stage(H=0.89,P=0.82),recurrence risk(H=2.48,P=0.47),pathological type(H=4.54,P=0.20),TSH level(H=4.24,P=0.23)、 radioiodine dose(H=0.97,P=0.81),surgery scope(H=1.50,P=0.68),but in ps-Tg level(H=126.85,P<0.001)and ps-Tg/TSH ratio(H=114.9,P<0.001).The optimal cut-off value of ps-Tg for ER group was 4.58ng/m L(sensitivity 80.9%,specificity 74.9%),with an area under the ROC curve of 0.83(95%CI:0.782-0.885).The optimal cut-off value of ps-Tg for SIR group was 22.50ng/m L(sensitivity 83.3%,specificity 89.3%),with an area under the ROC curve of 0.88(95%CI:0.763-0.994).The optimal cut-off value of ps-Tg/TSH ratio for ER group was 0.052(sensitivity 84.6%,specificity 67.7%),with an area under the ROC curve of 0.81(95%CI: 0.757-0.865).The optimal cut-off value of ps-Tg/TSH ratio for SIR group was 0.706(sensitivity 75.0%,specificity 93.0%),with an area under the ROC curve of 0.88(95%CI:0.758-0.997).There was a significant difference of composition ratio among group 1 [ER 69 cases(87.3%),IDR 10 cases(12.7%),BIR 0 case,SIR 0 case ],group 2 [ER 77 cases(62.7%),IDR 36 cases 29.2%),BIR 8 cases(6.5%),SIR 2 case(1.6%)] and group 3 [ER 20 cases 19.8%),IDR 32 cases(31.7%),BIR 39 cases(38.6%),SIR 10 cases(9.9%)](group1 with group 2,P<0.001;group1 with group 3,P<0.001;group2 with group 3,P<0.001).Conclusion: The serum ps-Tg level and ps-Tg/TSH ratio can be used for predicting radioiodine therapeutic response in non-distant-metastatic DTC patients,The higher the value,the worse the prognosis.