[Analysis of risk factors for central lymph node metastasis in papillary thyroid microcarcinoma]

Objective: To analyze the risk factors of lymph node metastasis in central region of patients with papillary thyroid microcarcinoma (PTMC). To evaluate the reliability of different risk factors on the prognosis of cervical lymph node metastasis in PTMC patients, and to provide the clinical support for PTMC in the central area. Methods: The clinical data of 700 patients with PTMC treated with surgery from January 2015 to July 2017 were analyzed retrospectively. Risk factors for lymph node metastasis in central region were analyzed by single factor analysis, multivariate Logistic regression analysis and receiver operating characteristic curve (ROC) curve. Results: Central lymph node metastasis (CLNM) rate was 48.29% (338/700). Multifactor analysis indicated that age≤45 years old, male, multifocality, capsule invasion, the tumor calcification and tumor diameter ≥5 mm were independent risk factors for CLNM in patients with PTMC. In the risk prediction of CLNM, the optimal critical value of diameter prediction was 7 mm and the area under the curve (AUC) of ROC=0.647. The optimal threshold for age prediction was 41 years old and AUC=0.597. Single factor analysis for ROC curve showed that gender factor AUC=0.588, tumor number factor AUC=0.627, tumor location factor AUC=0.613. and calcification factor AUC=0.603. The ROC curve of multiple risk factors was analyzed according to age, gender, diameter, location, number of cancer foci and calcification, and AUC=0.768. Conclusions: Age less than 45 years old, male, multiple cancer foci, focal invasion and capsule invasion, calcification, and tumor diameter ≥5 mm are independent risk factors for CLNM of PTMC. With an accumulation of multiple risk factors, CLNM risk increases, and central lymph node dissection should be recommend.