Analysis of the risk factors for central lymph node metastasis of cN0 papillary thyroid microcarcinoma: A retrospective study.

OBJECTIVE Cervical lymph node (CLN) metastasis (CLNM) can be found in some patients with CLN-negative (cN0) papillary thyroid microcarcinoma (PTMC), while the risk factors are still unknown. This study aimed to examine the risk factors of CLNM in patients with cN0 PTMC, contributing to screening cN0 PTMC patients with high risk in CLNM for preventive CLN dissection (CLND). METHODS This retrospective study included consecutive patients pathologically diagnosed with cN0 PTMC and who underwent surgery at the General Surgery Department of China-Japan Friendship Hospital between 07/2016 and 01/2020. The patients were grouped according to whether CLNM was present. Factors associated with CLNM were analyzed, and a risk prediction model was established in logistic regression analysis, and their predictive power was evaluated by receiver operating characteristic curves (ROC). RESULTS Finally, 171 patients were included; among them, 71 (41.5%) had CLNM. There were 32 males and 139 females. The multivariable analysis showed that males (OR = 5.619, 95%CI: 2.186-14.446; P < 0.001), age ≤45 years (OR = 2.982, 95%CI: 1.446-6.151; P = 0.003), adjacent to dorsal membrane (OR = 3.022, 95%CI: 1.430-6.387; P = 0.004), and irregular borders (OR = 4.332, 95%CI: 1.104-17.000; P = 0.036) were independent risk factors of CLNM. The risk prediction model composed of the four risk factors showed a relatively high AUC, at 0.760. When the cut-off was 0.38, the sensitivity was 67.6%, and the specificity was 73.0%. CONCLUSION Male sex, age ≤45 years, adjacent to dorsal membranes, and irregular borders are independent risk factors for CLNM in patients with cN0 PTMC. This might help identify cN0 PTMC patients needing preventive CLND.