The Value of Stimulated Thyroglobulin Before the First Radioactive Iodine Treatment in Metastasis for Differentiated Thyroid Carcinoma

BACKGROUND: To evaluate the value of preablative stimulated thyroglobulin (ps-Tg) before the first radioactive ablation iodine (RAI) treatment to predict the postoperative metastasis of DTC. METHODS: A total of 235 DTC patients, who underwent total thyroidectomy and neck lymph node dissection, were enrolled. On the basis of the presence or absence of metastasis, all patients were divided into metastasis (M1) and non-metastasis (M0) groups. Besides, the patients in the M1 group were further divided into two subgroups according to sites of metastasis. These groups included cervical lymph node metastasis and distant metastasis groups. Subsequently, the level of serum ps-Tg was measured 3 - 4 days before the first RAI ablation treatment, whereas 131I whole-body imaging and SPECT/CT tomography were performed 5 - 7 days after radio ablation. Subsequently, the Mann Whitney U test was used to compare the different levels of ps-Tg between the two groups. Additionally, the relationship between ps-Tg and the metastasis of DTC was analyzed through correlation analysis, regression analysis, and the ROC curve. RESULTS: The ps-Tg level in the M1 group was higher than that in the M0 group. Further analysis discovered that the ps-Tg in the distant metastasis group was higher than that in the cervical lymph node metastasis and non-metastasis groups. Also, the ps-Tg level was positively correlated with distant metastasis (r = 0.599, p = 0.000). Besides, the results of multivariate logistic regression analysis outlined that the level of ps-Tg was an independent risk factor for the development of distant metastasis (OR = 1.008, p = 0.018). Subsequently, the results from the ROC analysis also showed a good diagnostic performance for ps-Tg in treating distant metastasis (AUC = 0.964, p = 0.000), and the optimal cutoff value was 61.87 ng/mL. CONCLUSIONS: The ps-Tg in patients with DTC before the first RAI ablation treatment is an independent risk factor and a meaningful indicator in predicting postoperative distant metastasis.