title: Focus on high-risk DTC patients: high postoperative serum thyroglobulin level is a strong predictor of disease persistence and is associated to progression-free survival and overall survival.
abstract: BACKGROUND
  No parameters predicting recurrence are available for high-risk differentiated thyroid cancer (DTC) patients, and 2-year-follow-up is required to modify the initial prognostic classification. High thyroglobulin (Tg) levels before ¹³¹I-remnant-ablation, during L-thyroxine-withdrawal (ablation-Tg) have undetermined predictive/prognostic significance in low-risk DTC patients. Our study aimed to assess the positive predictive value (PPV) of ablation-Tg in high-risk DTC patients and to evaluate whether high ablation-Tg levels were associated with progression-free-survival (PFS) and overall survival (OS).
  
  
  METHODS
  We selected 243 high-risk DTC patients. All patients underwent total thyroidectomy and ¹³¹I-remnant-ablation (initial therapy). Clinical data obtained during a median 5-year follow-up were used to assess the response and outcome. The association between disease persistence/recurrence after initial therapy, ablation-Tg, and other risk-factors (T, N, G, histology, and MACIS score) was evaluated through univariate and multivariate analyses, as was the association between PFS, OS ablation-Tg, and other risk factors.
  
  
  RESULTS
  Ablation-Tg of 50 μg/L or greater displayed the highest PPV(97%) for disease persistence. In the univariate analysis, high levels of ablation-Tg were confirmed in patients with persistent disease after initial therapy: the higher the odds ratios, the higher the ablation-Tg levels. On multivariate analysis, ablation-Tg was the best predictive factor, especially on comparing patients with ablation-Tg levels of 50 μg/L or greater and those with ablation-Tg less than 2 μg/L (adjusted OR, 818). In a multivariate Cox model, ablation-Tg was the factor most closely associated with PFS (HR, 65.9). The prognostic value of ablation-Tg was confirmed by the overall-survival curves and adjusted risk estimates (adjusted HR=26.7).
  
  
  CONCLUSIONS
  Ablation-Tg levels of 50 μg/L or greater are a valuable initial predictor of disease persistence/recurrence in high-risk DTC patients. A significant association emerged between high ablation-Tg levels of 50 μg/L or greater and both progression-free survival (PFS) and overall survival (OS).
authors.affiliation: Nuclear Medicine Unit, Galliera Hospital, Genoa, Italy. arnoldo.piccardo@galliera.it
authors.forename: Arnoldo
authors.initials: A
authors.lastname: Piccardo
authors.forename: Federico
authors.initials: F
authors.lastname: Arecco
authors.forename: Matteo
authors.initials: M
authors.lastname: Puntoni
authors.forename: Luca
authors.initials: L
authors.lastname: Foppiani
authors.forename: Manlio
authors.initials: M
authors.lastname: Cabria
authors.forename: Stefania
authors.initials: S
authors.lastname: Corvisieri
authors.forename: Anselmo
authors.initials: A
authors.lastname: Arlandini
authors.forename: Vania
authors.initials: V
authors.lastname: Altrinetti
authors.forename: Roberto
authors.initials: R
authors.lastname: Bandelloni
authors.forename: Fabio
authors.initials: F
authors.lastname: Orlandi
mesh_terms: D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011182:Postoperative Care; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012307:Risk Factors; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood* / Q000473:pathology / Q000601:surgery*; D013965:Thyroidectomy; D016896:Treatment Outcome
chemical_list: D013954:Thyroglobulin