目的：探讨cN0 期甲状腺乳头状微小癌（PTMC）的临床特点及中央区淋巴结隐性转移的危险因素。方法：回顾性分析372 例行甲状腺切除术及预防性中央区淋巴结清扫cN0 期甲状腺乳头状癌（PTC）患者临床资料，将其中250 例PTMC 患者（肿瘤直径≤ 1.0 cm）作为研究组，122 例普通PTC 患者（肿瘤直径>1.0~2.0 cm）作为对照组，通过比较两组患者临床病理及影像学资料，分析PTMC 的临床特点及中央区淋巴结隐性转移的危险因素。结果： 研究组与对照组中央区颈部淋巴结转移率分别为32.8%（82/250） 和42.6%（52/122），差异无统计学意义（P>0.05）。单因素分析显示，研究组中央淋巴结转移与肿瘤大小、多灶性肿瘤、包膜侵润有关（均P<0.05），而与结节的超声特征及其他因素无关（均P>0.05）； 对照组中央淋巴结转移与各研究因素均无明显关系（均P>0.05）。多因素分析发现，肿瘤大小（OR=2.916，95% CI=1.19~4.37）、多灶性肿瘤（OR=1.230，95% CI=0.68~2.75）、包膜侵润（OR=1.923，95% CI=1.06~3.70） 是PTMC 中央区淋巴结转移的危险因素（均P<0.05）。结论：cN0 期PTMC 中央区淋巴结转移率与普通PTC 相似，肿瘤大小、多灶性肿瘤、包膜侵润是cN0 期PTMC 淋巴结转移的危险因素。
Risk factors for occult central lymph node metastasis in cN0 papillary thyroid microcarcinoma
Objective: To investigate the clinical characteristics and the risk factors for occult central cervical lymph node metastasis in cN0 papillary thyroid microcarcinoma (PTMC). Methods: The clinical data of 372 patients with papillary thyroid carcinoma (PTC) at cN0 stage undergoing thyroidectomy plus prophylactic central neck dissection were retrospectively analyzed. Of the patients, 250 cases with PTMC (tumor diameter ≤1.0 cm) were regarded as study group and the other 122 cases with common PTC patients (tumor diameter >1.0–2.0 cm) served as control group. The clinical features and risk factors for central cervical lymph node metastasis of PTMC were analyzed by comparing the clinicopathologic and imaging data between the two groups of patients. Results: The incidence of central lymph node metastasis for study group and control group was 32.8% (82/250) and 42.6% (52/122) respectively, and the difference had no statistical significance (P>0.05). Univariate analysis showed that the central cervical lymph node metastasis in study group was significantly associated with tumor size, multifocality and extrathyroidal invasion (all P<0.05), but was unrelated to nodule ultrasound features and other factors (all P>0.05); the central cervical lymph node metastasis in control group was irrelevant to any of the analyzed factors (all P>0.05). Multivariate analysis identified that tumor size (OR=2.916, 95% CI=1.19–4.37), multifocality (OR=1.230, 95% CI=0.68–2.75) and extrathyroidal invasion (OR=1.923, 95% CI=1.06–3.70) were risk factors for central cervical lymph node metastasis of PTMC (all P<0.05). Conclusion: The incidence of central cervical lymph node metastasis in cN0 PTMC is similar to that in common PTC, and the risk factors are tumor size , multiple lesions and extrathyroidal invasion.