Clinical And Pathologic Predictors Of Neck Lymph Node Metastasis In Papillary Thyroid Microcarcinoma

Objective:This study is aimed to identify the clinical and pathologic factors associated with lymph node metastasis（LNM）including central lymph node metastasis（CLNM）in clinically lymph node negative（CN₀）PTMC patients and lateral lymph node metastasis（LLNM）.The results of our study might be helpful in making optimal therapeutic decision in PTMC patients.Methods:This retrospective cohort study included PTMC patients who underwent primary thyroidectomy with neck dissection at the Department of General Surgery,the Hospital between January 2014 and January 2017.Statistics on the size,age,gender,Hashimoto’s thyroiditis,multifocality,Vascular invasion,extrathyroidal extensions,Capsular invasion,Distant metastasis explore the reasons of central lymph node metastasis and lateral lymph node metastasis.We also discuss the meaning of central lymph node dissection（CLND）.Results:On univariate analyses,Male gender,age<45 years,tumor size>0.55cm,multifocality,Vascular invasion,Capsular invasion and extrathyroidal extension were significantly associated with a high prevalence of CLNM.On logistics regression analysis,male gender,age<45year,tumor size>0.55 cm,multifocality and Capsular invasion were found to be independent predictors of CLNM.However,extrathyroidal extension and Vascular invasion were not independent predictors of high prevalence of CLNM.On univariate analyses,Male gender,tumor size>0.55cm,Vascular invasion,Capsular invasion,extrathyroidal extension and Distant metastasis were significantly different between LLN-positive and LLN-negative groups.On logistics regression analysis,male gender,Capsular invasion,and Extrathyroidal extension were found to be independent predictors of LLNM.However,tumor size>0.55cm and Vascular invasion were not independent predictors of high prevalence of LLNM.All of 55 patients with LLNM defined as LLNM with CLNM.Conclusion:we found a high incidence of CLNM in clinically lymph node-negative PTMC patients.Subclinical CLNM in PTMC patients might be predicted by the following factors:male sex,age<45 years,tumor size>0.55 cm,capsular invasion and multifocality.LLNM in PTMC patients might be predicted by the following factors:male sex,extrathyroidal extension and capsular invasion.According to the analysis,the rate of CLNM in PTMC patients are high,and those with risk factors tend to develop into LLNM.The postoperative complications of CLND are temporary,and with the improvement of technical level and rich experience,the incidence of postoperative complications is decreasing.These findings support that patients with PTMC are likely to benefit from CLND.