RISK FACTORS FOR CENTRAL LYMPH NODE METASTASES IN PATIENTS WITH PAPILLARY THYROID MICROCARCINOMA

Objectives: Papillary thyroid carcinoma with a maximum tumor diameter no more than 10 mm is defined as papillary thyroid microcarcinoma (PTMC). The proportion of newly diagnosed PTMCs has increased significantly in recent years. Different guidelines have different comments about optimal management of PTMC, especially on prophylactic central lymph node (CLN) dissection. The aim of the present study was to analyze the risk factors for CLN metastases in patients with PTMC. Methods: A total of 4,389 patients underwent thyroid surgery at our center from January 2017 to March 2018, and 2,129 patients with PTMC were selected and assessed retrospectively. The relationship between CLN metastases and clinicopathologic features of PTMC were analyzed by both univariate and multivariate analyses. Results: Of the 2,129 patients with PTMC, CLN metastases were confirmed by pathology in 923 patients. Univariate and multivariate analyses found several independent factors associated with CLN metastases. They were male gender (odds ratio [OR], 1.694; 95% confidence interval [CI], 1.386 to 2.071; P<.001), younger age (<45 years) (OR, 2.687; 95% CI, 2.196 to 3.288; P<.001), larger tumor size (>5 mm) (OR, 2.168; 95% CI, 1.782 to 2.636; P<.001), positive CLN metastases via ultrasound (OR, 4.939; 95% CI, 3.534 to 6.902; P<.001), and multifocality (OR, 1.424; 95% CI, 1.176 to 1.724; P<.001). Conclusion: CLN metastases are common in PTMC patients. Male gender, younger age (<45 years), larger tumor size (>5 mm), positive CLN metastases via ultrasound, and multifocality are independent risk factors for CLN metastases. Our data should be considered in the decision-making process related to performing CLN dissection.