title: Is there a role for unstimulated thyroglobulin velocity in predicting recurrence in papillary thyroid carcinoma patients with detectable thyroglobulin after radioiodine ablation?
abstract: BACKGROUND
  In the follow-up of papillary thyroid cancer (PTC) patients treated with curative thyroidectomy and radioiodine ablation, raised thyroglobulin (Tg) predicts recurrence with reasonable sensitivity and specificity. However, a proportion of patients present with raised Tg level but no other clinical evidence of disease. Only limited data on Tg kinetics have been reported to date. Here we aim to evaluate the prognostic and predictive significance of nonstimulated serum Tg velocity (TgV).
  
  
  METHODS
  Consecutive PTC patients treated with curative thyroidectomy and radioiodine ablation between 2003 and 2010 were analyzed. Patients with at least one detectable Tg measurement (>0.2 ng/mL) were included. TgV was defined as the annualized rate of Tg change. Logistic regression analyses were performed to evaluate the role of TgV in the prediction of disease recurrence. The optimal TgV cutoff was assigned by receiver-operating characteristic curve analysis. Overall survival of patients above versus below the TgV cutoff were determined by the Kaplan-Meier method and compared.
  
  
  RESULTS
  Of a total of 501 patients, 87 had at least one Tg value >0.2 ng/mL; in these latter patients, 29 (33.3%) developed recurrence. TgV was an independent predictor of the recurrence. TgV ≥0.3 ng/mL per year predicted recurrence with a sensitivity of 83.3% and specificity of 94.4%. Patients with TgV below the cutoff had a significantly better overall survival (p = 0.038).
  
  
  CONCLUSIONS
  TgV predicts recurrence with high sensitivity and specificity, and is a prognosticator of survival in postthyroidectomy and postablation PTC patients with raised Tg.
authors.affiliation: Department of Medicine, Division of Hematology and Oncology, Queen Mary Hospital, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Hilda
authors.initials: H
authors.lastname: Wong
authors.forename: Kai P
authors.initials: KP
authors.lastname: Wong
authors.forename: Thomas
authors.initials: T
authors.lastname: Yau
authors.forename: Vikki
authors.initials: V
authors.lastname: Tang
authors.forename: Roland
authors.initials: R
authors.lastname: Leung
authors.forename: Joanne
authors.initials: J
authors.lastname: Chiu
authors.forename: Brian Hung-Hin
authors.initials: BH
authors.lastname: Lang
mesh_terms: D055011:Ablation Techniques; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000097:blood* / Q000601:surgery*; D002291:Carcinoma, Papillary; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood*; D011237:Predictive Value of Tests; D012372:ROC Curve; D013954:Thyroglobulin / Q000097:blood*; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000097:blood* / Q000601:surgery*; D013965:Thyroidectomy; D013997:Time Factors; D055815:Young Adult
chemical_list: D007457:Iodine Radioisotopes; D013954:Thyroglobulin