Dynamic Changes Of Serum Trab Concentration After¹³¹I Treatment In Graves’ Disease And Its Association With Early Hypothyroidism

Objective：To study the dynamic change of serum thyrophin receptor antibody (TRAb) inpatients with Graves’ disease after131I radiotherapy and investigate its association withearly hypothyroidism.Methods:240cases with Graves’ disease admitted in endocrinology department of LinyiPeople’s Hospital between march2009and october2011that were treated with131I.ALLof them conform to the diagnostic and treatment criteria of thyroid disease in China (2009).All the patients were not treated with anti-thyroid drugs or surgery before131I treatment,the dose of131I (mCi)=thyroid mass (g) x131I doses expected per gram of thyroid (uCi/g)/24h131I absorption rate, then make the conversion of uci into mci. Thyroid quality wascomprehensive determined, estimated by thyroid imaging combined with EmissionComputed Tomography and B ultrasonic examination results. The thyroid tissue dose ofper gram is determined according to the course of the disease, thyroid size, texture, age,and previous treatment situation. All240patients were followed up for1year, and weredivided into early hypothyroidism group and non-early hypothyroidism group according tothe occurrence of the early hypothyroidism after treatment in one year.(see table1).Collecting5ml fasting venous blood in the morning before and3,6,12months after131Itreatment, testing the FT3, FT4, TSH and TRAb immediately. Comparision with TRAbconcentration before and3.6.12months after131I treatment in each group and TRAbconcentration between two groups. Comparision with the age of onset, FT3, FT4, thyroidweight,131I dose and other general baseline clinical data. Results:1. The difference on the age of onset, FT3, FT4, thyroid weight,131I dose and othergeneral baseline clinical data was not statistically significant at P＞0.05(table1).2. In all240patients,134patients became precociously hypothyroid, while13patients did not. TRAb results before and3.6.12months after131I treatment are shown intable2. In both early hypothyroidism group and non-early hypothyroidism group, serumTRAb titer presented dynamic change which increased at the third month, reached thehighest level at the sixth month and returned to the baseline level at the twelfth month.(figure1).The comparison of TRAb concentration between6months after131I treatmentwith before131I treatment was statistically significant in early hypothyroidism group (t=3.859, P <0.01), and6months after treatment compared with3months was statisticallysignificant (t=2.361, P <0.05),12month after treatment compared with6months wasstatistically significant (t=2.925, P <0.05).The comparison of TRAb concentrationbetween before and3,6,12months after131I treatment had no statistical significance innon-early hypothyroidism group (P>0.05). According to the comparison between thetwo groups at each time point, TRAb concentration6months after131I treatment in theearly hypothyroidism group was obviously higher than that in non-early hypothyroidismgroup, the difference was statistically significant (F=13.967, P <0.01). There were nostatistical significance at the comparison between other each point (P>0.05)(figure2).Conclusions:1. The dynamic change of serum TRAb before and after131I radiotherapy is closelyrelated with the probability of the early hypothyroidism.2. The dynamic change of serum TRAb plays an important role in the judgment ofprognosis after131I treatment in Graves’ disease.