title: Markedly elevated thyroglobulin levels in the preoperative thyroidectomy patient correlates with metastatic burden.
abstract: BACKGROUND
  Thyroglobulin (Tg) is a marker of tumor recurrence during thyroid cancer follow-up. While helpful in the postoperative setting, the clinical significance of preoperative Tg measurements remains unclear. The aim of the study was to determine if preoperative Tg levels are indicative of underlying malignancy or burden of metastatic disease.
  
  
  METHODS
  A retrospective review of a prospectively collected database at an academic medical center of all thyroidectomy patients with a measured preoperative Tg level was conducted. Patients were grouped by Tg level into quartiles for initial univariate analysis, followed by multivariable analysis of variance.
  
  
  RESULTS
  Between 2007 and 2012, 611 patients met criteria. Quartile breakdown was as follows: ≤19 ng/mL, 19.1-54 ng/mL, 54.1-151 ng/mL, and >151 ng/mL. Patients' age and gender were equivalent. Hashimoto's thyroiditis was most common in the lowest Tg group (24% versus 11%-12%, P < 0.01). While cancer was more common in the low Tg, metastatic disease was most common in the high Tg group. Specimen weight increased with increasing Tg levels (P < 0.01). Body mass index, gland weight, cancer, and Hashimoto's and metastatic disease were entered into a multivariable analysis. Only gland weight and metastatic disease correlated with Tg levels (both P < 0.001). All patients with Tg > 5000 ng/mL had metastatic disease (n = 6).
  
  
  CONCLUSIONS
  Although preoperative Tg levels are not associated with a diagnosis of cancer, they are associated with the presence of metastatic disease. All patients with a Tg > 5000 ng/mL had significant disease burden. In patients with concern for metastatic disease, preoperative serum Tg may be a useful marker to aid decision making.
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Oltmann
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Glen
authors.initials: G
authors.lastname: Leverson
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Suzy Hsiu-I
authors.initials: SH
authors.lastname: Lin
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: David F
authors.initials: DF
authors.lastname: Schneider
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Herbert
authors.initials: H
authors.lastname: Chen
authors.affiliation: Section of Endocrine Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin. Electronic address: sippel@surgery.wisc.edu.
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Sippel
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000097:blood / Q000556:secondary / Q000601:surgery; D000231:Adenocarcinoma, Papillary / Q000097:blood / Q000556:secondary / Q000601:surgery; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D005260:Female; D006044:Goiter, Nodular / Q000097:blood; D050031:Hashimoto Disease / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000097:blood; D011300:Preoperative Care; D011379:Prognosis; D012189:Retrospective Studies; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood* / Q000556:secondary / Q000601:surgery; D013965:Thyroidectomy; D047368:Tumor Burden
chemical_list: D014408:Biomarkers, Tumor; D013954:Thyroglobulin
keywords: Hashimoto's thyroiditis; Metastatic burden; Metastatic disease; Multi-nodular goiter; Thyroglobulin; Thyroid cancer; Thyroidectomy; Thyroiditis