SPECT/CT诊断低危甲状腺乳头状癌术后131I治疗后淋巴结转移发生率及其影响因素

目的 评估低危甲状腺乳头状癌（PTC）患者术后¹³¹I治疗后SPECT/CT诊断转移淋巴结的发生率，并探讨其影响因素。方法 回顾性分析术后¹³¹I治疗前根据2015版美国甲状腺协会指南分为低危的409例PTC患者资料，¹³¹I治疗后5天行全身显像（WBS）和断层融合显像（SPECT/CT），根据显像结果及随访资料判断SPECT/CT上有无转移淋巴结的存在。比较有转移淋巴结及无转移淋巴结患者的临床资料，分析SPECT/CT上存在转移淋巴结的影响因素，利用ROC曲线预测存在淋巴结转移的最佳界值。结果 ¹³¹I治疗后SPECT/CT发现91例患者存在转移淋巴结，发生率为22.25%（91/409）。单因素分析显示肿瘤大小、刺激性甲状腺球蛋白（sTg）及T分期是存在转移淋巴结的影响因素（P均<0.05）；Logistic分析显示sTg水平是影响转移淋巴结存在的独立危险因素。ROC曲线分析显示，sTg预测转移淋巴结存在的最佳界值为4.01 ng/ml，敏感度87.3%，特异度60.1%。结论 低危PTC患者术后及¹³¹I治疗后SPECT/CT显示转移淋巴结的发生率较高，肿瘤较大及sTg水平高是其影响因素，sTg水平高是预测淋巴结转移的重要指标。

SPECT/CT in assessment of incidence and impact factors of lymph nodes metastasis of low-risk papillary thyroid cancer after surgicgal operation and 131I treatment

Objective To evaluate the incidence and probable impact factors of metastatic lymph nodes on SPECT/CT in patients with low-risk thyroid papillary cancer (PTC) after surgical operation and ¹³¹I treatment. Methods Data of 409 patients with low risk PTC based on 2015 edition of American Thyroid Association guidelines after surgical operation and before ¹³¹I treatment were analyzed. Whole body scintigraphy(WBS) and SPECT/CT were performed 5 days after ¹³¹I treatment. According to imaging results and follow-up data, the presence of metastatic lymph nodes on SPECT/CT was estimated. Clinical data of patients with and without metastatic lymph nodes were compared, the impact factors of metastatic lymph nodes on SPECT/CT were analyzed, and optimal threshold value of lymph node metastasis was predicted with ROC curve. Results SPECT/CT showed metastatic lymph nodes in 91 patients with low risk PTC after ¹³¹I treatment, with an incidence of 22.25% (91/409). Univariate analysis showed that the tumor size, stimulated thyroglobulin (sTg) and T stage were impact factors for the existence of metastatic lymph nodes (all P<0.05). Logistic regression showed that sTg was an independent predictor for assessment of metastatic lymph nodes in patients with low-risk PTC. ROC curve analysis showed that the optimal cutoff of sTg in predicting metastatic lymph nodes was 4.01 ng/ml, with sensitivity of 87.3% and specificity of 60.1%. Conclusion The incidence of metastatic lymph nodes on SPECT/CT is relative high in patients with low risk PTC after surgical operation and ¹³¹I treatment. The large tumor and high level of sTg are the impactfactors of the existence of metastatic lymph nodes, and the latter is an important index to predict the existence of metastatic lymph nodes.