目的: 分析术后接受¹³¹I治疗的乳头状甲状腺微小癌（papillary thyroid microcarcinoma, PTMC）与乳头状甲状腺非微小癌（papillary thyroid non-microcarcinoma, non-PTMC）病人的临床病理特征，并比较治疗转归的差异，以期指导PTMC的¹³¹I治疗决策。方法: 纳入2015年1月至2020年12月在天津医科大学总医院核医学科¹³¹I治疗的1 118例PTC病人，采用卡方检验及秩和检验比较PTMC组与non-PTMC组病人临床病理特征、¹³¹I治疗情况及治疗反应的差异，Kaplan-Meier法绘制两组的治疗反应不佳(incomplete response, IR)率曲线。结果: PTMC组病人多灶性、累及双叶的比例均高于non-PTMC组，腺外侵犯、T4、N1b、刺激性甲状腺球蛋白(stimulated thyroglobulin, sTg)>10 μg/L及高危复发风险的比例低于non-PTMC组（P<0.05）。PTMC组多数病人首次接受清甲治疗，而non-PTMC组中更多病人接受辅助及清灶治疗（P<0.05）。两组病人¹³¹I治疗反应、疗效满意(excellent response, ER)率和IR率的差异均无统计学意义，IR率曲线差异也无统计学意义（P>0.05）。结论: PTMC具有一定的侵袭性。经综合评估和规范¹³¹I治疗后，PTMC和non-PTMC病人治疗转归大致相同。PTMC的界定对¹³¹I治疗决策的指导价值极其有限。

Objective To analyze the clinicopathological data of patients with papillary thyroid microcarcinoma (PTMC) and papillary thyroid non-microcarcinoma (non-PTMC) who received ¹³¹I therapy retrospectively, and compare the therapeutic response of the two groups of patients, so as to guide ¹³¹I therapy decisions for PTMC patients. Methods A total of 1 118 patients with papillary thyroid carcinoma (PTC) underwent ¹³¹I therapy in the Department of Nuclear Medicine, Tianjin Medical University General Hospital from January 2015 to December 2020 were enrolled. Chi-square test and Mann-Whitney U test were used to compare the differences of clinicopathological features and ¹³¹I therapy， therapeutic response between two groups. The incomplete response （IR）rate curves of the two groups were plotted by Kaplan-Meier analysis.Results The proportion of patients with multifocal, involvement of bilateral thyroid lobes in PTMC group were higher than those in non-PTMC group, and the proportion of patients with extra-thyroid extension, T4, N1b, stimulated thyroglobulin(sTg)>10 μg/L, and high risk stratified were lower than those in non-PTMC group (P<0.05). Most patients in PTMC group received remnant ablation for the first time, while more patients in non-PTMC group received adjuvant therapy and therapy for known disease (P<0.05). There was no statistically significant difference in ¹³¹I therapeutic response, the rates of excellent response(ER) and IR in two groups, and the differences in curves of IR rate between the two groups were also no statistically significance (P>0.05). Conclusions PTMC has a certain degree of invasiveness. As long as the patients were comprehensively evaluated and the standard ¹³¹I therapy was adopted, the treatment outcomes of patients with PTMC and non-PTMC were roughly the same. Therefore, the clinical value of the definition of PTMC is extremely limited in the formulation of ¹³¹I therapeutic dose regimens.