title: [Preablative serum thyroglobulin as predictor of disease-free survival in differentiated thyroid cancer].
abstract: BACKGROUND
  Serum thyroglobulin (sTg) is an excellent marker of persistence or recurrence of disease in differentiated thyroid cancer (DTC), however its role as prognostic factor has not been fully established.
  
  
  OBJECTIVE
  To assess the value of the preablative thyroglobulin (pTg) as predictor of disease-free survival in DTC.
  
  
  METHODS
  Retrospective study of 104 patients with low and intermediate risk DTC subjected to total thyroidectomy and 131iodine ablation. TSH, pTg and thyroglobulin antibodies (AbTg) were determined by chemiluminescence. Patients with distant metastases or presence of AbTg were excluded. Results were analyzed using receiving operating characteristic (ROC) curves.
  
  
  RESULTS
  During the 40 ± 29 months of follow-up (range 6-132), 14 of 104 (13%) patients had recurrence of disease. pTg was an independent indicator to predict disease-free survival. Using a pTg cutoff of < 10 ng/ml the negative predictive value was 99%, sensitivity 93%, specificity 82%, positive likelihood ratio (LR) 5.2 and negative LR 0,087.
  
  
  CONCLUSIONS
  pTg value is useful as a prognostic marker in predicting disease-free survival in DTC patients with low or intermediate risk of recurrence.
authors.forename: René E
authors.initials: RE
authors.lastname: Díaz
authors.forename: Jesús
authors.initials: J
authors.lastname: Véliz
authors.forename: Nelson
authors.initials: N
authors.lastname: Wohllk
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D002277:Carcinoma / Q000097:blood / Q000628:therapy*; D002291:Carcinoma, Papillary; D002677:Chile; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood*; D011237:Predictive Value of Tests; D011379:Prognosis; D012372:ROC Curve; D012189:Retrospective Studies; D013954:Thyroglobulin / Q000097:blood*; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000097:blood / Q000628:therapy*; D013965:Thyroidectomy / Q000379:methods; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D007457:Iodine Radioisotopes; D013954:Thyroglobulin