title: Elevated serum thyroglobulin levels at the time of ablative radioactive iodine therapy indicate a worse prognosis in thyroid cancer: an Australian retrospective cohort study.
abstract: BACKGROUND
  Serum thyroglobulin is used as a surrogate marker for well-differentiated thyroid carcinoma recurrence. This study investigates whether thyroglobulin measured at the time of ablative radioactive iodine therapy predicts disease-free survival.
  
  
  METHODS
  A retrospective review was conducted of patients with well-differentiated thyroid carcinoma presenting from 1989 to 2010 at the Royal Prince Alfred Hospital, New South Wales, Australia. Disease-free survival of patients with a significantly elevated stimulated thyroglobulin level (27.5 µg/l or higher) at the time of ablative radioactive iodine therapy was compared to that of patients without a significantly elevated thyroglobulin level using univariate analysis.
  
  
  RESULTS
  Patients with a thyroglobulin level of 27.5 µg/l or higher had an increased relative risk of disease recurrence of 4.50 (95 per cent confidence interval = 1.35-15.04). If lateral neck dissection was required at the time of surgery, patients also had an increased relative risk of macroscopic disease recurrence of 4.94 (95 per cent confidence interval = 1.47-16.55).
  
  
  CONCLUSIONS
  An elevated thyroglobulin level of 27.5 µg/l or higher at the time of ablative radioactive iodine therapy is a prognostic indicator for macroscopic disease recurrence in well-differentiated thyroid carcinoma.
authors.affiliation: Department of Head and Neck Surgery,Royal Prince Alfred Hospital,Sydney,New South Wales,Australia.
authors.forename: T J
authors.initials: TJ
authors.lastname: Matthews
authors.affiliation: Department of Endocrinology,Royal Prince Alfred Hospital,Sydney,New South Wales,Australia.
authors.forename: E
authors.initials: E
authors.lastname: Chua
authors.affiliation: Department of Endocrinology,Royal Prince Alfred Hospital,Sydney,New South Wales,Australia.
authors.forename: A
authors.initials: A
authors.lastname: Gargya
authors.affiliation: Department of Head and Neck Surgery,Royal Prince Alfred Hospital,Sydney,New South Wales,Australia.
authors.forename: J
authors.initials: J
authors.lastname: Clark
authors.affiliation: Sydney Head and Neck Cancer Institute,Chris O'Brien Lifehouse at Royal Prince Alfred Hospital,New South Wales,Australia.
authors.forename: K
authors.initials: K
authors.lastname: Gao
authors.affiliation: Department of Head and Neck Surgery,Royal Prince Alfred Hospital,Sydney,New South Wales,Australia.
authors.forename: M
authors.initials: M
authors.lastname: Elliott
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000097:blood; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000532:radiotherapy / Q000601:surgery; D011379:Prognosis; D012189:Retrospective Studies; D012306:Risk; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood / Q000175:diagnosis / Q000532:radiotherapy* / Q000601:surgery; D013965:Thyroidectomy
chemical_list: D014408:Biomarkers, Tumor; D007457:Iodine Radioisotopes; D013954:Thyroglobulin
keywords: Biochemical Tumor Markers; Disease-Free Survival; Iodine; Prognosis; Thyroglobulin; Thyroid Neoplasms