关键词: 甲状腺肿瘤, 分化型甲状腺癌, 甲状腺球蛋白, 治疗前刺激性甲状腺球蛋白, 刺激性甲状腺球蛋白, 甲状腺球蛋白减少指数, 碘, 预测, 长期缓解

Abstract: Background　Differentiated thyroid cancer（DTC）patients need long-term follow-up services due to post-treatment persistence and high risks of recurrence.So it is essential to explore effective parameters for estimating the outcome and frequency of follow-up for these patients.Preablation stimulated thyroglobulin（ps-Tg）is an important prognostic parameter for DTC.However，its prognostic value in DTC（especially locally advanced DTC）patients has not been reported in China.Objective　To evaluate the value of ps-Tg，stimulated thyroglobulin（s-Tg）and thyroglobulin reduction index（TRI）in predicting long-term remission status in DTC（including locally advanced DTC）patients treated with thyroid remnant ablation with 131I，to identify the responses of the patients to treatment，and based on this，to deliver personalized management，or to alleviate the frequency of follow-ups in those with good responses to decrease psychological and economic burdens caused by frequent follow-ups.Methods　 From the long-term follow-up database of 992 DTC patients developed by Department of Breast & Thyroid Surgery，Suining Central Hospital，An Affiliated Hospital of Chongqing Medical University，those receiving thyroid remnant ablation with 131I between January 2004 and January 2012 were selected between October 2018 and January 2019.General characteristics（including gender，age，diameter of DTC，T/N/M staging，DTC invasion，lymph node capsule rupture，ps-Tg，s-Tg and TRI）and prognosis of the patients were collected.Multivariate Cox regression analysis was used to analyze the prognostic factors of patients with DTC.ROC curve analysis was carried out to explore the value of ps-Tg，s-Tg and TRI in predicting the long-term remission status in patients with DTC，and locally advanced DTC（T3-T4/Nx-N1 staging）.Log-rank test was performed to compare the survival status between groups.Results　 N staging，ps-Tg，s-Tg and TRI were associated with the prognosis of DTC patients in multivariate Cox regression analysis（P<0.05）.T staging，N staging，distribution of ps-Tg，s-Tg and TRI were also associated with the prognosis in multivariate Cox regression analysis（P<0.05）.ROC analysis identified ps-Tg of 10.0 μg/L（AUC=0.831），s-Tg of 1.0 μg/L（AUC=0.846）and TRI of 60%（AUC=0.722）as sensitive predictors for long-term remission in DTC patients.The sensitivity of ps-Tg，s-Tg and TRI was 74.1%，76.9% and 77.7%，respectively，while the specificity was 73.4%，74.7% and 72.8%，respectively.In the sub-population with locally advanced DTC，ps-Tg of 10.0 μg/L（AUC=0.864），s-Tg of 1.0 μg/L（AUC=0.859）and TRI of 62.5%（AUC=0.764）were effective indicators for predicting long-term remission with the sensitivity of 96.1%，54.2% and 74.0%，respectively.The specificity of ps-Tg，s-Tg and TRI was 55.4%，97.3% and 63.8%，respectively.The rate of long-term remission was significantly reduced when ps-Tg≥10.0 μg/L and s-Tg≥1.0 μg/L（P<0.05）.The cutoffs were also applicable to locally advanced DTC.DTC patients with TRI>60.0% achieved higher rate of long-term remission than that of those with TRI≤60.0%（P<0.05），while in locally advanced tumors this cutoff became 62.5%（P<0.05）.Conclusion　This study identified ps-Tg<10.0 μg/L，sTg<1.0 μg/L，and TRI>60.0% as highly sensitive predictors for excellent response in patients with DTC.And ps-Tg<10.0 μg/L，sTg<1.0 μg/L，and TRI>62.5% may be used for those with locally advanced DTC（T3-T4/ Nx-N1 staging）.

Key words: Thyroid neoplasms, Differentiated thyroid cancer, Thyroglobulin, Preablation stimulated thyroglobulin, Stimulated thyroglobulin, Thyroglobulin reduction index, Iodine, Forecasting, Long-term remission status