title: Predicting Factors for Bilaterality in Papillary Thyroid Carcinoma with Tumor Size <4 cm.
abstract: In the 2015 American Thyroid Association guidelines, either lobectomy or total thyroidectomy was recommended for thyroid cancer <4 cm without extrathyroidal extension (ETE) and lymph node (LN) metastasis. Therefore, the purpose of this study was to investigate factors predictive of bilaterality in papillary thyroid carcinoma (PTC) patients with tumor size <4 cm.
  
  
  
  This study retrospectively reviewed 3296 conventional PTC patients who underwent total thyroidectomy with central neck dissection and/or lateral neck dissection between January 2008 and June 2015.
  
  
  
  In overall conventional PTC patients, per 10-year age increment (adjusted odds ratio [OR] = 1.153, p < 0.001), BRAF mutation positivity (adjusted OR = 1.447, p = 0.002) and multifocality (adjusted OR = 3.895, p < 0.001) were independent predictors for bilaterality. In conventional PTC patients with tumor size 1-4 cm, per 10-year age increment (adjusted OR = 1.289, p < 0.001), BRAF mutation positivity (adjusted OR = 1.560, p = 0.012), multifocality (adjusted OR = 4.220, p < 0.001), and N1b (adjusted OR = 1.570, p = 0.007) were independent predictors for bilaterality. In conventional PTC patients with tumor size <1 cm, BRAF mutation positivity (adjusted OR = 1.327, p = 0.042) and multifocality (adjusted OR = 3.530, p < 0.001) were found to be independent predictors for bilaterality.
  
  
  
  When multifocality and BRAF mutation positivity are observed in PTC patients with tumor size <4 cm, total thyroidectomy may be considered. If lobectomy is performed in PTC patients with multifocality and BRAF mutation positivity, meticulous follow-up is needed to detect hidden malignancies in the contralateral lobe.
authors.affiliation: 1 Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine , Seoul, South Korea .
authors.forename: Seo Ki
authors.initials: SK
authors.lastname: Kim
authors.affiliation: 1 Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine , Seoul, South Korea .
authors.forename: Inhye
authors.initials: I
authors.lastname: Park
authors.affiliation: 2 Department of Surgery, Changwon Gyeongsang National University Hospital, Gyeongsang National University School of Medicine , Changwon, South Korea .
authors.forename: Jung-Woo
authors.initials: JW
authors.lastname: Woo
authors.affiliation: 3 Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine , Changwon, South Korea .
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Lee
authors.affiliation: 1 Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine , Seoul, South Korea .
authors.forename: Jun-Ho
authors.initials: JH
authors.lastname: Choe
authors.affiliation: 1 Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine , Seoul, South Korea .
authors.forename: Jung-Han
authors.initials: JH
authors.lastname: Kim
authors.affiliation: 1 Division of Breast and Endocrine Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine , Seoul, South Korea .
authors.forename: Jee Soo
authors.initials: JS
authors.lastname: Kim
mesh_terms: D000328:Adult; D002291:Carcinoma, Papillary / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009154:Mutation; D037981:Neck Dissection; D009367:Neoplasm Staging; D009378:Neoplasms, Multiple Primary / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D016017:Odds Ratio; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D012189:Retrospective Studies; D012307:Risk Factors; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D013965:Thyroidectomy; D047368:Tumor Burden
chemical_list: C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf
keywords: BRAF mutation; bilaterality; multifocality; papillary thyroid carcinoma; total thyroidectomy