title: Factors predictive of papillary thyroid micro-carcinoma with bilateral involvement and central lymph node metastasis: a retrospective study.
abstract: BACKGROUND
  The optimal resection extent for papillary thyroid microcarcinoma (PTMC) remains controversial. The objective of the study was to investigate risk factors of bilateral PTMC and central lymph node metastasis (CLNM) to guide surgical strategies for PTMC patients.
  
  
  METHODS
  We retrospectively reviewed 211 PTMC patients who underwent total thyroidectomy (TT) and 122 clinical lymph node-negative (cN0) cases that underwent prophylactic central lymph node dissection (CLND) between 2010 and 2011. The frequency, pattern, and predictive factors for bilateral PTMC and CLNM in these patients were studied using univariate and multivariate analysis with respect to the following variables: age, gender, extrathyroidal extension (ETE), T stage, with Hashimoto thyroiditis (HT), tumor size and multifocality based on final pathology, and preoperative evaluation using ultrasonography (US).
  
  
  RESULTS
  Fifty-four of 211 (25.6%) patients had bilateral PTMC. In multivariate analysis, multifocality (P < 0.001, OR = 23.900) and tumor size ≥7 mm (P = 0.014, OR = 2.398) based on US were independent predictive factors for bilateral PTMC which was also independently associated with multifocality (P < 0.001, OR = 29.657) and tumor size ≥7 mm (P = 0.005, OR = 2.863) based on final pathology. Among 122 cN0 patients who underwent prophylactic CLND, we found 49.2% of patients had CLNM. CLNM was independently associated with men, age <50 years and tumor size ≥7 mm based on final pathology or preoperative US.
  
  
  CONCLUSIONS
  TT should be considered for PTMC patients who are found multifocality and tumor size ≥7 mm based on preoperative US. CLND need be considered in cN0 patients who are men, aged <50 years or tumor size ≥7 mm based on preoperative US.
authors.affiliation: Department of Oncology, The First Affiliated Hospital of Wenzhou Medical College, No. 2 Fuxue Lane, Wenzhou, Zhejiang, China.
authors.forename: Yi-Li
authors.initials: YL
authors.lastname: Zhou
authors.forename: Er-Li
authors.initials: EL
authors.lastname: Gao
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Han
authors.initials: H
authors.lastname: Yang
authors.forename: Gui-Long
authors.initials: GL
authors.lastname: Guo
authors.forename: Xiao-Hua
authors.initials: XH
authors.lastname: Zhang
authors.forename: Ou-Chen
authors.initials: OC
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D044963:Biopsy, Fine-Needle; D002277:Carcinoma; D002291:Carcinoma, Papillary; D005260:Female; D006801:Humans; D016015:Logistic Models; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D012189:Retrospective Studies; D012307:Risk Factors; D013223:Statistics as Topic; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000601:surgery; D055815:Young Adult