Predictive factors for central lymph node metastasis in patients with cN0 papillary thyroid carcinoma: A systematic review and meta-analysis

Background and objectives: Recently, some single-institution studies have reported risk factors of CLNM in cN0 PTC patients, but results from those studies are not consistent. The meta-analysis aimed to identify some risk factors that can be predictive of CLNM in cN0 PTC patients. Methods: We performed a systematic search for relevant literature published prior to December 2015 using the following search engines: PubMed, EMBASE, Ovid and Web of Science. We included retrospective, prospective, and observational studies that investigated the risk factors for CLNM in patients with cN0 PTC. Results: Thirty-one studies, including 37,355 patients with cN0 PTC from seven countries were included in the meta-analysis. The pooled analysis indicated that age<45 years (OR = 1.57, 95%CI: 1.48-1.66, P < 0.001), male gender (OR = 1.79, 95%CI: 1.69e1.91, P < 0.001), tumor size>10 mm (OR = 2.61, 95% CI: 2.27-3.00, P < 0.001), bilaterality (OR = 1.52, 95%CI: 1.31-1.77, P < 0.001), multifocality (OR = 1.46, 95%CI: 1.31-1.61, P < 0.001), extracapsular invasion (OR = 2.10, 95%CI: 1.81-2.43, P < 0.001), angio-lymphatic invasion (OR = 8.02, 95%CI: 5.00-12.87, P < 0.001), high histologic risk (OR = 2.62, 95%CI: 2.13 -3.22, P < 0.001) and BRAF(V600E) mutation (OR: 1.78, 95%CI: 1.38-2.30, P < 0.001) were significantly associated with CLNM, and upper third location (OR = 0.54, 95%CI: 0.43-0.67, P < 0.001) and lymphocytic thyroiditis (OR = 0.64, 95%CI: 0.42-0.97, P = 0.034) were decreased risk factors of CLNM. Conclusions: We identified several predictive factors for CLNM in cN0 PTC patients. Some certain risk factors could be considered in preoperative clinical decision regarding the necessity of prophylactic central lymph node dissection in cN0 PTC patients. (C) 2016 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.