Risk Factors for Central Lymph Node Metastasis in CN0 Papillary Thyroid Carcinoma: A Systematic Review and Meta-Analysis.

Abstract

BACKGROUND:Central lymph node metastasis (CLNM) is common in papillary thyroid carcinoma (PTC). Prophylactic central lymph node dissection (PCLND) for patients with clinically negative central compartment lymph nodes (CN0) remains controversial. The phrase "clinically negative" is used to indicate that patients exhibited no clinical evidence of CLNM by ultrasonography (US) or computerized tomography (CT) preoperatively. In this study, we analyze the risk factors for CLNM in CN0 patients. METHODS:The PUBMED and SCIE databases were systematically searched for works published through January 31, 2015. All of the patients included in this study underwent thyroidectomy+PCLND. Revman 5.3 software was used to analyze the data. RESULTS:Twenty studies and 9084 patients were included in this meta-analysis. The following variables were associated with an increased risk of CLNM in CN0 patients: age 2 cm for PTC patients (OR = 2.98, 95% CI 2.08-4.28, p 0.5 cm for papillary thyroid microcarcinoma (PTMC) patients (OR = 2.30, 95% CI = 1.71-3.09, p 1 cm) exhibited a higher risk factor associated with CLNM than PTMC (tumor size < 1 cm) (OR = 2.83, 95% CI = 2.15-3.72, p<0.00001). Bilateral tumors (OR = 1.21, 95% CI = 0.92-1.58, p = 0.17) and lymphocytic thyroiditis (OR = 0.88, 95% CI = 0.71-1.09, p = 0.25) had no association with CLNM in CN0 patients. CONCLUSIONS:Our systematic review identified several clinical features associated with CLNM in CN0 patients, including age, sex, multifocality, size, location, lymphovascular invasion, capsular invasion, and extrathyroidal extension. These factors should guide the application of PCLND in CN0 patients.