title: Clinical risk factors for central lymph node metastasis in papillary thyroid carcinoma: a systematic review and meta-analysis.
abstract: BACKGROUND
  Prophylactic central lymph node dissection (CLND) in clinically node-negative patients remains controversial, and predictive factors for central lymph node metastasis (CLNM) in patients with papillary thyroid carcinoma (PTC) are not well defined. Herein, we conducted a systematic review to quantify the clinicopathologic factors predictive for CLNM in patients with PTC.
  
  
  METHODS
  A systematic search of electronic databases (PubMed, Embase, Cochrane CENTRAL, Scopus and Wanfang Database) for studies published until July 2014 was performed. Cohort, case-control studies and randomized controlled trials that examined clinical risk factors of CLNM were included.
  
  
  RESULTS
  Twenty-five studies (4 prospective and 21 retrospective studies) involving 7,719 patients met final inclusion criteria. From the pooled analyses, male gender (OR 1.93, 95% CI 1.40 to 2.64), tumour multifocality (OR 1.93, 95% CI 1.62 to 2.30), tumour size >0.5 cm (OR 3.48, 95% CI 2.24 to 5.41), capsular invasion (OR 1.91, 95% CI 1.36 to 2.67), extrathyroidal extension (OR 2.42, 95% CI 1.58 to 3.71), lymphovascular invasion (OR 13.29, 95% CI 5.61 to 31.48) and lateral lymph node metastasis (OR 14.33, 95% CI 5.34 to 38.50) were significantly associated with increased risk of CLNM, while age >45 years (OR 0.65, 95% CI 0.51 to 0.83) and lymphocytic thyroiditis (OR 0.70, 95% CI 0.53 to 0.92) resulted in decreased risk of CLNM. Bilaterality and tumour location were not significantly associated with CLNM development (all P > 0.05).
  
  
  CONCLUSIONS
  Our analysis identified several clinicopathologic factors associated with CLNM. These findings may guide the necessity and extent of prophylactic CLND and ultimately improve the outcomes of patients with PTC.
authors.affiliation: Department of General Surgery, Shandong University Qilu Hospital, Shandong, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Qu
authors.affiliation: Department of General Surgery, Shandong University Qilu Hospital, Shandong, China.
authors.forename: Guo-rui
authors.initials: GR
authors.lastname: Sun
authors.affiliation: Department of Respiratory Medicine, Provincial Hospital Affiliated to Shandong University, Jinan, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of General Surgery, Shandong University Qilu Hospital, Shandong, China.|Department of Respiratory Medicine, Provincial Hospital Affiliated to Shandong University, Jinan, China.
authors.forename: Qing-si
authors.initials: QS
authors.lastname: He
mesh_terms: D000367:Age Factors; D002277:Carcinoma / Q000473:pathology*; D002291:Carcinoma, Papillary / Q000473:pathology*; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D009333:Neck; D037981:Neck Dissection; D009361:Neoplasm Invasiveness; D012307:Risk Factors; D012737:Sex Factors; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000473:pathology*; D013967:Thyroiditis, Autoimmune / Q000453:epidemiology; D047368:Tumor Burden