目的: 分析中危甲状腺乳头状癌(papillary thyroid carcinoma, PTC)病人¹³¹I治疗后复发因素。方法: 纳入2018年1月至2020年5月本院254例中危PTC病人¹³¹I治疗后复发情况，通过卡方检验及多因素分析探索¹³¹I治疗后复发的主要因素。结果: 34例（13.4%）中危病人¹³¹I治疗后复发。原发灶大小、淋巴结转移分期及术后¹³¹I治疗前刺激性甲状腺球蛋白（pre-ablation stimulated thyroglobulin, psTg）与肿瘤复发相关。通过受试者工作特征(receiver operating characteristic, ROC)曲线分析，psTg 为25.6 μg/L时，是预测PTC复发最佳截断值。进一步多因素分析发现淋巴结转移分期与psTg水平是预测PTC复发的独立因素。联合这两个指标，当淋巴结分期N1b且psTg ≥25.6 μg/L，¹³¹I治疗后肿瘤复发率为58.3%；当淋巴结分期N1a且psTg <25.6 μg/L时，¹³¹I治疗后肿瘤复发率仅2.3%。结论: 淋巴结转移分期与psTg水平是PTC复发的重要指标，联合这两个指标有助于预测¹³¹I治疗后肿瘤复发。

Objective To analyze the recurrence factors of the patients with intermediate risk papillary thyroid carcinoma (PTC) after radioactive iodine treatment (RAIT). Methods A total of 254 intermediate risk PTC patients after RAIT from January 2018 to May 2020 in our hospital were enrolled into this study. Chi square test and multivariate analysis were applied to analyze the main recurrence factors after RAIT. Results Thirty four (13.4%) patients with intermediate risk PTC relapsed after RAIT. The primary tumor size, lymph node metastasis staging, and pre-ablation stimulated thyroglobulin (psTg) were associated with tumor recurrence. According to the receiver operating characteristic （ROC） curve, psTg 25.6 μg/L was the best cutoff value for predicting recurrence. Further multivariate analysis revealed that lymph node metastasis staging and psTg levels were independent factors of predicting PTC recurrence. When the patients with N1b and psTg≥25.6 μg/L, the incidence of tumor recurrence after RAIT was 58.3%. While the patients with N1a and psTg<25.6 μg/L, the incidengce of tumor recurrence was only 2.3%. Conclusions Lymph node metastasis staging and psTg level are the important indicators of PTC recurrence, and combining these two indicators can help predict tumor recurrence after RAIT.