title: Lymph node fine-needle aspiration washout thyroglobulin in papillary thyroid cancer: Diagnostic value and the effect of thyroglobulin antibodies.
abstract: OBJECTIVE
  Thyroglobulin (Tg) assessment in the needle washout after fine-needle aspiration biopsy (FNAB) of a suspicious neck lymph node (LN) is known to improve the diagnostic accuracy in patients with papillary thyroid cancer (PTC). However, there is still controversy on the best diagnostic cut-off levels for FNAB-Tg and whether thyroglobulin antibody (TgAb) positivity affects FNAB-Tg. The objectives of this study were to determine (i) the diagnostic power of different cut-offs for FNAB-Tg and (ii) if serum TgAb(+) negatively affects the FNAB-Tg evaluation.
  
  
  METHODS
  This was a retrospective cohort study analyzing PTC patients with suspicious neck LNs, in a university hospital setting, from October 2009 to October 2013. In total, 103 patients with PTC (226 LNs) undergoing ultrasound-guided FNAB for LNs were included. Cytology and FNAB-Tg levels were compared in reference to LN histopathology and the effect of TgAb(+) on FNAB-Tg levels was evaluated.
  
  
  RESULTS
  The diagnostic accuracies of FNAB-Tg cut-off of 1 and 10 ng/mL were 94.1% and 88.2%, respectively. Raising the cut-off from 1 to 10 ng/mL led to decreased sensitivity rates (91.9% vs. 83.9%). The receiver operating characteristic curve analysis demonstrated that the best FNAB-Tg cut-off was 1.2 ng/mL. There were no LNs with an FNAB-Tg ≥ 10 ng/mL that turned out to be cytologically or histopathologically benign. FNAB-Tg levels of the histopathologically malignant LNs were similar between TgAb (+) and TgAb (-) patients (p = 0.546). Serum Tg predicted FNAB-Tg levels above 1 ng/mL (p = 0.002) and FNAB-Tg predicted malignant histopathology (p = 0.004), both independently of the TgAb status of the patient.
  
  
  CONCLUSIONS
  FNAB-Tg ≥ 1 ng/mL has a superior diagnostic power, irrespective of TgAb (+), in PTC patients with suspected LN involvement.
authors.affiliation: a Department of Endocrinology and Metabolism , Gazi University Faculty of Medicine , Ankara , Turkey.
authors.forename: Ceyla
authors.initials: C
authors.lastname: Konca Degertekin
authors.affiliation: a Department of Endocrinology and Metabolism , Gazi University Faculty of Medicine , Ankara , Turkey.
authors.forename: Mehmet Muhittin
authors.initials: MM
authors.lastname: Yalcin
authors.affiliation: a Department of Endocrinology and Metabolism , Gazi University Faculty of Medicine , Ankara , Turkey.
authors.forename: Turgay
authors.initials: T
authors.lastname: Cerit
authors.affiliation: a Department of Endocrinology and Metabolism , Gazi University Faculty of Medicine , Ankara , Turkey.
authors.forename: Cigdem
authors.initials: C
authors.lastname: Ozkan
authors.affiliation: a Department of Endocrinology and Metabolism , Gazi University Faculty of Medicine , Ankara , Turkey.
authors.forename: Isilay
authors.initials: I
authors.lastname: Kalan
authors.affiliation: a Department of Endocrinology and Metabolism , Gazi University Faculty of Medicine , Ankara , Turkey.
authors.forename: Ozlem Turhan
authors.initials: OT
authors.lastname: Iyidir
authors.affiliation: a Department of Endocrinology and Metabolism , Gazi University Faculty of Medicine , Ankara , Turkey.
authors.forename: Alev Eroglu
authors.initials: AE
authors.lastname: Altinova
authors.affiliation: a Department of Endocrinology and Metabolism , Gazi University Faculty of Medicine , Ankara , Turkey.
authors.forename: Mujde
authors.initials: M
authors.lastname: Akturk
authors.affiliation: a Department of Endocrinology and Metabolism , Gazi University Faculty of Medicine , Ankara , Turkey.
authors.forename: Fusun
authors.initials: F
authors.lastname: Toruner
authors.affiliation: b Department of General Surgery , Gazi University Faculty of Medicine , Ankara , Turkey.
authors.forename: Murat
authors.initials: M
authors.lastname: Akin
authors.affiliation: a Department of Endocrinology and Metabolism , Gazi University Faculty of Medicine , Ankara , Turkey.
authors.forename: Nuri
authors.initials: N
authors.lastname: Cakir
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000378:metabolism*; D044963:Biopsy, Fine-Needle / Q000592:standards*; D002277:Carcinoma / Q000175:diagnosis*; D002291:Carcinoma, Papillary; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D001323:Autoantibodies; C006606:anti-thyroglobulin
keywords: Fine-needle aspiration biopsy; lymph node thyroglobulin; papillary thyroid cancer; thyroglobulin antibody