title: Thyroglobulin - what is the postoperative threshold for the suspicion of thyroid cancer recurrence in the absence of anti-Tg antibody measurement?
abstract: BACKGROUND
  Thyroglobulin (Tg) is used as a postoperative marker for the follow-up of patients with thyroid carcinoma, but there is no consensus regarding the value that may indicate possible recurrence. Aim. To evaluate Tg levels as a marker for recurrence of thyroid carcinoma.
  
  
  METHODS
  Demographics and survival of 80 patients who underwent total thyroidectomy for well-differentiated thyroid cancer were analysed and related to Tg levels. Tg measurements were performed when patients were euthyroid, after completion of treatment.
  
  
  RESULTS
  The median Tg value was 1.3 ng/ml. Higher values were found in males, high-risk patients and patients with recurrent disease. Using the median Tg value as cut-off, patients were divided into two groups (group I ≤1.3 ng/ml and group II >1.3 ng/ml). There was a significant correlation between values >1.3 ng/ml and recurrence. When survival was related to Tg values, there was a tendency towards worse prognosis in group II. The best predictive cut-off value for recurrence was found to be 1.3 ng/ml, which had a sensitivity of 77% and a specificity of 57%.
  
  
  CONCLUSIONS
  Although low, a cut-off Tg level of 1.3 ng/ml represents a simple indication for further investigation in patients receiving thyroxine after completion of treatment for thyroid cancer, in the absence of measurement of anti-Tg auto-antibodies.
authors.affiliation: 1st Department of Surgery, University General Hospital of Alexandroupolis, Greece. mikpapageo@cytanet.com.cy
authors.forename: M S
authors.initials: MS
authors.lastname: Papageorgiou
authors.forename: N
authors.initials: N
authors.lastname: Liratzopoulos
authors.forename: G
authors.initials: G
authors.lastname: Minopoulos
authors.forename: K J
authors.initials: KJ
authors.lastname: Manolas
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood; D002277:Carcinoma / Q000097:blood* / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood* / Q000473:pathology; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood* / Q000473:pathology* / Q000601:surgery; D013965:Thyroidectomy; D055815:Young Adult
chemical_list: D001323:Autoantibodies; C006606:anti-thyroglobulin; D013954:Thyroglobulin