Radioiodine treatment (30mCi) for postsurgical remnant ablation in patients with differentiated thyroid carcinoma: Comparative analysis of patient preparation using conventional thyroid hormone (LT4/T3) withdrawal or recombinant human TSH

Abstract

Purpose: Few reports have examined the use of recombinant human TSH(rhTSH) for ablation of postsurgical thyroid remnants after low dose RI (radioactive iodine) therapy, compared with conventional thyroid hormone withdrawal. The aim of the present study was to explore the effectiveness of each patient preparation method before RI ablation(30mCi) of the remnant thyroid in patients with differentiated thyroid carcinoma(DTC).Methods: This study included three groups of patients, enrolled consecutively. From February 2006 to March 2007, 291 patients were enrolled and randomized, after total thyroidectomy, to a 4-week LT4 withdrawal group(Group, I, n=89), a 2-week T3 withdrawal group(Group II, n=133), and a rhTSH administration group(Group III, n=69). Quality-of-life(QoL) was determined at the time of ablation.Results: Patients in the three groups did not differ significantly in baseline characteristics or TNM staging. In all study groups, serum TSH levels showed very good stimulation(mean, 82.24±18.21 mU/L), without significant between-group differences(p=0.5213). Follow-up examinations performed 12 months after ablation were satisfactory in all study patients, without significant between-preparation differences(p=0.2061). QoL was better preserved in Group III than in Groups I and II(p<0.0001). However, there was no QoL difference at the time of ablation between Groups I and II. Conclusion: Our study indicates that use of rhTSH preserves QoL in patients undergoing RI ablation, and affords an ablation success rate comparable to that seen after thyroid hormone withdrawal. However, ablation preparation using withdrawal of LT3 for 2 weeks did not prevent development of profound hypothyroidism, as also occurred when LT4 alone was withdrawn for 4 weeks.