title: Diagnostic value of thyroglobulin measurement with fine-needle aspiration biopsy for lymph node metastases in patients with a history of differentiated thyroid cancer.
abstract: OBJECTIVE
  The aim of this study was to evaluate the diagnostic value of FNA-Tg for detecting lymph node metastases in patients with a history of differentiated thyroid cancer (DTC).
  
  
  METHODS
  A total of 58 patients with DTC diagnosis and evidence of single or multiple suspicious cervical lymph nodes were assessed. All underwent total or near-total thyroidectomy with (35 cases) or without (23 cases) radioiodine (RAI) ablation, followed by thyroid stimulating hormone (TSH) suppression therapy. A total of 68 lymph nodes were examined by ultrasound-guided fine needle aspiration (US-FNA) for both cytological examination and FNA-Tg measurement. Serum Tg and anti-thyroglobulin antibody (TgAb) levels were also measured. Diagnostic performance including sensitivity, specificity, accuracy, positive (PPV) and negative predictive value (NPV) of FNAC and FNA-Tg were calculated and compared. The Spearman's rank correlation coefficient was used to estimate the relationship between FNA-Tg and serum TgAb.
  
  
  RESULTS
  The FNA-Tg levels were significantly higher with DTC metastatic lymph nodes (median 927.7 ng/mL, interquartile range 602.9 ng/mL) than non-metastatic lymph nodes (median 0.1 ng/mL, interquartile range 0.4 ng/mL) (p<0.01). Considering 1.0 ng/mL as a threshold value for FNA-Tg, the sensitivity, specificity, accuracy, PPV and NPV of FNA-Tg were 95.7%, 95.5%, 95.6%, 97.8% and 91.3%, respectively. The sensitivity and accuracy of the combination of FNAC and FNA-Tg were significantly higher than that of FNAC alone (p<0.05). The diagnostic performance of FNA-Tg was not significantly different between cases with or without RAI ablation, and the serum TgAb levels did not interfere with FNA-Tg measurements.
  
  
  CONCLUSIONS
  Measurement of FNA-Tg is useful. The combination of FNAC and FNA-Tg is more sensitive and accurate for detecting lymph node metastases in patients with a history of DTC than FNAC alone. Serum TgAbs appear to be irrelevant for measurement of FNA-Tg.
authors.affiliation: Department of Surgery, China-Japan Union Hospital, Jilin University, China E-mail : sunhuijlu@163.com, maqingjiejlu@163.com.
authors.forename: Hai-Shan
authors.initials: HS
authors.lastname: Zhang
authors.forename: Ren-Jie
authors.initials: RJ
authors.lastname: Wang
authors.forename: Qing-Feng
authors.initials: QF
authors.lastname: Fu
authors.forename: Shi
authors.initials: S
authors.lastname: Gao
authors.forename: Bu-Tong
authors.initials: BT
authors.lastname: Sun
authors.forename: Hui
authors.initials: H
authors.lastname: Sun
authors.forename: Qing-Jie
authors.initials: QJ
authors.lastname: Ma
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000378:metabolism / Q000556:secondary* / Q000628:therapy; D014408:Biomarkers, Tumor / Q000032:analysis*; D044963:Biopsy, Fine-Needle; D002291:Carcinoma, Papillary / Q000378:metabolism / Q000556:secondary* / Q000628:therapy; D017115:Catheter Ablation; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007118:Immunoassay; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D013954:Thyroglobulin / Q000032:analysis*; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000628:therapy; D013965:Thyroidectomy
chemical_list: D014408:Biomarkers, Tumor; D013954:Thyroglobulin