Abstract
1301
Objectives To study the factors that affect the efficacy of the 131I thyroid remnant ablation of post-surgical differentiated thyroid carcinoma patients.
Methods A retrospective analysis was performed of 183 post-surgical differentiated thyroid carcinoma patients treated with 131I thyroid remnant ablation. These patients have an average age of 46.86±14.98 years ranging from 7 to 81. One hundred and sixty-five of the patients had papillary cancer and remaining 18 had follicular thyroid cancer. The 131I remnant ablation was done following the guideline of Chinese Association of Nuclear Medicine. About 3 to 6 months later, the efficacy of the ablation was evaluated by the 131I whole body scan. The criterion of the successful ablation was defined as no radioactive uptake in the thyroid bed. The data of age, gender, pathological type, metastasis or not, the size of thyroid remnant, TSH level, rate of iodine uptake, the ablative dose and the efficacy of ablation was recorded. Binary regression and chi-square test was analyzed to study the main factors that affect the efficacy of ablation.
Results 1. Successful ablation at first dose was achieved in 109 patients (59.56%). 2. By Binary Logistic Regression,the size of thyroid residue and the ablative dose were the main factors that affect the efficacy of the ablation, Wald value was 8.59 and 6.40, p was 0.003 and 0.011 respectively. 3. By chi-square test, the ablation efficacy in patients with TSH>=30uIU/ml was higher than those with TSH<30uIU/ml, x2 was 7.291 and p was 0.007. There was no significant difference between patients with TSH<60uIU/ml and those with TSH>=60uIU/ml, x2 was 0.1511 and p was 0.697.
Conclusions The size of thyroid residue and the ablative dose are the main factors that affect the efficacy of radioiodine thyroid ablation. Though the TSH level is not the main factors, TSH still poses important effect on the ablation efficacy