title: Preoperative BRAF mutation has different predictive values for lymph node metastasis according to tumor size.
abstract: OBJECTIVE
  To investigate whether BRAF mutation of papillary thyroid carcinoma (PTC) has different predictive values for regional lymph node (LN) metastasis according to tumor size.
  
  
  METHODS
  Prospective cohort study. Setting. A tertiary hospital.
  
  
  METHODS
  From January 2009 to August 2009, the authors prospectively enrolled 102 consecutive patients with unifocal PTC based on the findings of ultrasonography-guided fine-needle aspiration biopsy (FNAB). BRAF mutation was tested on preoperative FNAB specimens. Total thyroidectomy and bilateral central neck dissection (± lateral neck dissection) was performed for all patients. Among 102 patients, 71 who were confirmed to have unifocal PTC by the surgical pathology were finally selected. The 71 patients were classified into 3 groups according to their tumor size: group I, ≤0.5 cm; group II, >0.5 cm and ≤1 cm; and group III, >1 cm. LN metastasis was evaluated in the surgical specimen as a dependent variable. The authors investigated whether BRAF mutation is predictive of LN metastasis in each group.
  
  
  RESULTS
  Overall, BRAF mutation was a significant predictor of LN metastasis (P = .045). When patients were classified into 3 groups, frequency of LN metastasis increased with tumor size: 4.8%, 50.0%, and 66.7% (P < .001). However, the frequency of BRAF mutation was not different among 3 groups: 61.9%, 56.3%, and 72.2% (P = .536). BRAF mutation was predictive of LN metastasis only in group II (P = .026).
  
  
  CONCLUSIONS
  BRAF mutation of PTC may have differential predictive values for LN metastasis, according to tumor size.
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Inje University College of Medicine, Haeundae Paik Hospital, Pusan, South Korea.
authors.forename: Yoon Kyoung
authors.initials: YK
authors.lastname: So
authors.forename: Young-Ik
authors.initials: YI
authors.lastname: Son
authors.forename: Joo Yeon
authors.initials: JY
authors.lastname: Park
authors.forename: Chung-Hwan
authors.initials: CH
authors.lastname: Baek
authors.forename: Han-Sin
authors.initials: HS
authors.lastname: Jeong
authors.forename: Man Ki
authors.initials: MK
authors.lastname: Chung
mesh_terms: D044963:Biopsy, Fine-Needle; D002277:Carcinoma; D002291:Carcinoma, Papillary; D016009:Chi-Square Distribution; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016015:Logistic Models; D008198:Lymph Nodes / Q000473:pathology*; D008297:Male; D015999:Multivariate Analysis; D009154:Mutation; D037981:Neck Dissection / Q000379:methods; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000379:methods; D011379:Prognosis; D011446:Prospective Studies; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D018570:Risk Assessment; D016019:Survival Analysis; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology / Q000556:secondary / Q000601:surgery*; D013965:Thyroidectomy / Q000379:methods
chemical_list: C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf