ABSTRACT
Objective:To analyze the risk factors of the number of central lymph node metastasis (CLNM) >5 in papillary thyroid microcarcinoma (PTMC) with clinical lymph node negative (cN0) .Methods:A total of 1567 cases of unilateral cN0 PTMC patients undergoing surgery at Endocrine and Breast Surgery Department of the First Affiliated Hospital of Chongqing Medical University from Jan. 2013 to Dec. 2018 were analyzed retrospectively. There were 405 cases of male and 1162 cases of female among them. According to the CLNM, they were divided into 0-5 and ≥5 groups. Clinicopathological characteristics of two groups were compared with Chi-square test and χ 2 test, et al. Results:The case of CLNM>5 involved was 4.1% (65/1567) .Univariate analysis showed that male, age ≤50 years old, tumor diameter> 8 mm, multifocal cancer all were related to CLNM>5 involved ( P<0.05) , multivariate logistic regression analysis found that male ( OR=1.886, P=0.017) , age ≤50 years ( OR=3.778, P=0.002) , tumor diameter>8 mm ( OR=2.483, P<0.001) and multifocal cancer ( OR=2.362, P=0.005) were independent risk factors for CLNM>5. Subgroup analysis showed that the number of Delphian lymph nodes metastasis≥1 ( OR=13.475, P<0.001) , pretracheal lymph nodes metastasis≥2 ( OR=41.695, P<0.001) , and Delphian+pretracheal lymph nodes metastasis≥2 ( OR=28.750, P<0.001) were also independent risk factors for CLNM>5. Conclusions:Unilateral PTMC patients who are male and age ≤50 years old with tumor diameter>8 mm, multifocal cancer have higher risk of central lymph nodes more than 5 involved, surgical treatment and prophylactic central neck dissection are recommended to such patients instead of long-term follow-up observation.Total thyroidectomy should be selected appropriately according to the intraoperative situation.