Prognostic value of serum stimulating thyroglobulin in metastatic radioactive iodine refractory differentiated thyroid cancer

Abstract

Purpose: To investigate the prognostic value of serum-stimulated thyroglobulin (ps-Tg) before the first 131I therapy in patients with metastatic radioactive iodine-refractory differentiated thyroid cancer (RR-DTC). Methods: From August 2017 to August 2020, the clinical data for 160 patients with thyroid papillary carcinoma (PTC) who received thyroidectomy and 131I treatment were analyzed retrospectively. Differences in clinical data and related thyroid indices were compared. Univariate and multivariate logistic regression analyses were used to analyze the related factors affecting the occurrence of RR-DTC. Receiver-operator characteristic (ROC) curves were used to determine the discriminative power of ps-Tg in predicting RR-DTC, while the Kaplan-Meier survival curve of ps-Tg for RR-DTC was drawn. Results: A total of 160 patients with thyroid cancer were enrolled, including 47 males, and 113 females (70.62 %). Overall mean age was 39 ± 13 years old. The follow-up results showed that 68 patients with thyroid cancer were refractory to radioactive iodine. The ps-Tg of the iodine-refractory group was higher than that of the iodine-receptive group (p < 0.001). Multivariate logistic regression showed that ps-Tg was an independent risk factor for RR-DTC (OR = 1.086, p = 0.000). The optimal cut-off value of ps-Tg for predicting progression to RR-DTC was 19.21 μg/L. Kaplan-Meier survival curve showed that the risk of iodine refractory in patients with thyroid cancer (≥ 19.21 μg/L) was higher than that of patients with thyroid cancer < 19.21 μg/L (p < 0.001). Conclusion: The ps-Tg before the first 131I therapy independently predicts the occurrence of metastatic RR-DTC when ps-Tg is greater than the risk of RR-DTC increase. This finding will be helpful in predicting the occurrence of RR-DTC, in order to determine the best time to start treatment and make individualized treatment decisions.