title: Postoperative-stimulated serum thyroglobulin measured at the time of 131I ablation is useful for the prediction of disease status in patients with differentiated thyroid carcinoma.
abstract: BACKGROUND
  This study was conducted to identify the relevant cutoff value and to evaluate the usefulness of postoperative-stimulated serum thyroglobulin (Tg) at the time of (131)I ablation for the prediction of disease status in patients with differentiated thyroid carcinoma (DTC) who received high-dose (131)I ablation therapy after total thyroidectomy.
  
  
  METHODS
  We analyzed 218 consecutively enrolled patients who were diagnosed with DTC and underwent total thyroidectomy. All patients underwent (131)I ablation at doses of 100-200 mCi, and stimulated serum Tg was measured at the time of (131)I ablation therapy. To assess disease-free status after (131)I ablation therapy, stimulated serum Tg levels, diagnostic whole-body scan (DxWBS) and neck ultrasonography (US) were performed 6-12 months after (131)I ablation.
  
  
  RESULTS
  The relevant cutoff value of postoperative stimulated Tg for the prediction of disease-free status was 2 ng/mL. A total of 138 patients (63.3%) showed values of <2 ng/mL. Postoperative-stimulated Tg < 2 ng/mL had a negative predictive value of 94.9%, which increased to 97.7% when low Tg was combined with negative neck US findings.
  
  
  CONCLUSIONS
  Postoperative-stimulated Tg at the time of (131)I remnant ablation is a useful biochemical marker for the prediction of disease status in patients with DTC. When high-dose (131)I remnant ablation is performed after total thyroidectomy, the stimulated Tg measurement and DxWBS that are usually performed 6-12 months after (131)I ablation therapy may be skipped, at least in low- and intermediate-risk patients with postoperative stimulated Tg of < 2 ng/mL and negative neck US findings.
authors.affiliation: Department of Internal Medicine, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea.
authors.forename: Ji In
authors.initials: JI
authors.lastname: Lee
authors.forename: Yun Jae
authors.initials: YJ
authors.lastname: Chung
authors.forename: Bo Youn
authors.initials: BY
authors.lastname: Cho
authors.forename: SeMin
authors.initials: S
authors.lastname: Chong
authors.forename: Ju Won
authors.initials: JW
authors.lastname: Seok
authors.forename: Sung Jun
authors.initials: SJ
authors.lastname: Park
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000097:blood*; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D005544:Forecasting; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011379:Prognosis; D012307:Risk Factors; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood* / Q000532:radiotherapy* / Q000601:surgery; D013965:Thyroidectomy; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D007457:Iodine Radioisotopes; D013954:Thyroglobulin