Correlation between 131I uptake and therapeutic efficacy in metastatic differentiated thyroid carcinoma: a retrospective multicenter study / 中华核医学与分子影像杂志

ABSTRACT

Objective:To investigate the correlation between 131I uptake and therapeutic efficacy in metastatic differentiated thyroid carcinoma (DTC). Methods:The clinical data of 138 patients with metastatic DTC (42 males, 96 females, age range 8-74 years) treated with 131I in nuclear medicine departments of 31 centers all over China were retrospectively analyzed. The lesional 131I uptake was quantitatively analyzed with target-to-nontarget (T/NT) ratio through the regions of interest in metastatic lesions confirmed by either planar or tomographic 131I SPECT/CT imaging. The efficacies of 131I treatment on the metastatic DTC were divided into complete remission (CR), partial remission (PR), stable disease (SD) and progress disease (PD) based on the change of the lesion diameter before and after the treatment. Factors which may affect therapeutic efficacy were assessed by the univariate (Kruskal-Wallis rank sum test, χ2 test and one-way analysis of variance) and binary logistic regression analyses. The receiver operating characteristic (ROC) curve of lesional T/NT ratio to predict the ineffectiveness of 131I therapy was performed. Results:A total of 1 165 efficacies were evaluated. The planar imaging results ( n=653) showed that there was no statistically significant difference of T/NT ratio among CR, PR, SD and PD groups ( χ2=4.15, P>0.05). The tomographic imaging results ( n=512) suggested CR, PR, SD and PD in 7.6%(39/512), 65.8%(337/512), 22.9%(117/512), and 3.7%(19/512) of individuals, respectively, and the T/NT ratio among the four groups was significantly different ( χ2=30.46, P<0.01). The univariate analysis also showed that age, stimulated thyroglobulin(sTg), 131I dose were the factors affecting therapeutic efficacy ( F or χ2 values 2.561, 7.095 and 8.799, all P<0.05). Furthermore, binary logistic regression analysis revealed that older patients (odds ratio ( OR)=1.034, P=0.022) or patients with lower lesional T/NT ( OR=1.086, P=0.006) had a higher probability of ineffectiveness. The area under ROC curve for T/NT ratio to predict ineffectiveness was 0.726, and the cut-off value was 6.2, with a sensitivity of 78.7%(107/136) and a specificity of 73.1%(275/376). Conclusions:131I therapy is an effective treatment for metastatic DTC. The age at the time of metastatic diagnosis and the lesional T/NT ratio are independent influential factors for ineffectiveness of 131I therapy. When the leisonal T/NT ratio is lower than 6.2, the inefficiency of 131I is higher.