中低危分化型甲状腺癌低剂量131I治疗后短期转归的临床分析

背景与目的：2015版美国甲状腺协会（American Thyroid Association，ATA）指南首次提出治疗反应评估体系（response-to-therapy assessment system，RTAS）。该研究根据此评估体系，探讨低剂量（1 110 MBq）¹³¹I在中低危分化型甲状腺癌（differentiated thyroid carcinoma，DTC）清甲治疗后短期内不同转归的影响因素。方法：回顾性分析2015年1月—2017年1月166例中低危DTC患者资料，男性50例，女性116例，平均年龄（39.61±10.23）岁。首次清甲剂量为1 110MBq，取得清甲前及清甲后6~12个月刺激性甲状腺球蛋白（stimulated thyroglobulin，sTg）及诊断性全身显像（diagnosticwhole body scan，Dx-WBS），根据结果分为最佳治疗反应（excellent response，ER）组与非最佳反应（non-excellent response，NER）组。采用两样本t检验、Mann-Whitney U秩和检验及χ²检验进行组间临床病理资料比较，采用Logistic回归分析影响清甲疗效的因素，采用受试者工作特征（receiver operating characteristic，ROC）曲线确定最佳界值。结果：ER组127例，NER组39例，ER率为76.5%（127/166）。治疗后短期随访ER组清甲治疗前sTg（preablative sTg，ps-Tg）明显低于NER组［1.5（0.04-30.57）ng/mL vs 17.6（0.04-21.52）ng/mL；U=2 479，P<0.05］，且性别、年龄差异有统计学意义，男性及年龄稍小者更易出现NER。多因素分析显示，ps-Tg水平、肿瘤大小、淋巴结转移数目、性别、年龄及多灶性均为影响清甲疗效的相关因素（OR：0.361~2.875）。ROC曲线分析显示，ps-Tg最佳临界值为2.0 ng/mL。结论：ps-Tg水平较低、病灶较小、淋巴结转移数目较少、男性、年龄较小及单灶患者清甲治疗后短期内更易达到ER；且以ps-Tg值2.0 ng/mL为最佳临界点，对预测治疗后短期临床转归有较高的灵敏度和特异度。

Clinical analysis of short-term outcome in low-to-intermediate-risk thyroid cancer after low-dose 131I therapy

Background and purpose: The concept of response-to-therapy assessment system (RTAS) was first proposed in the 2015 American Thyroid Association (ATA) guidelines. This study aimed to investigate the different short-term outcomes of thyroid ablation with low-dose (1 110 MBq) ¹³¹I for low-to-intermediate-risk thyroid cancer based on this system, and its probable influence factors. Methods: A total of 166 patients with differentiated thyroid carcinoma (DTC) ［50 males, 116 females; average age: (39.61±10.23) years］ undergoing first thyroid ablation with 1 100 MBq ¹³¹I from January 2015 to January 2017 were retrospectively observed. All patients underwent diagnostic whole body scan (Dx-WBS), and the stimulated thyroglobulin (sTg) was measured before ablation and 6-12 months after ablation respectively. According to above results, patients were divided into excellent response (ER) group and non-excellent response (NER) group. Clinical and pathological characteristics of 2 groups were compared usingtwo-sample t test, Mann-Whitney U test and χ² test. Logistic regression was used to identify the influence factors for efficacy of ¹³¹I ablation, and the cut-off value was determined by receiver operating characteristic (ROC) curve analysis. Results: There were 127 patients in ER group and 39 patients in NER group. The successful ablation rate was 76.5% (127/166). Patients in ER group showed lower preablative sTg (ps-Tg) compared with patients in NER group. The ps-Tg levels were 1.5 (0.04-30.57) ng/mL and 17.6 (0.04- 21.52) ng/mL respectively (U=2 479, P<0.05). Male and patient with younger age were more prevalent in NER group (P<0.05). Logistic regression showed that ps-Tg, tumor size, the number of metastatic lymph nodes, gender, age and multifocality were independent predictors for efficacy of ¹³¹I ablation (OR: 0.361-2.875). The optimal cut-off value of ps-Tg identified by ROC curve analysis was 2.0 ng/mL. Conclusion: The patients with lower ps-Tg, smaller diameter of tumor, fewer lymph node metastases, male, younger age and single lesion are more likely to have ER within a short period following thyroid ablation. Ps-Tg of 2.0 ng/mL is identified as cut-off value for predicting the short-term therapeutic response, which has preferable sensitivity and specificity.