Thyroglobulin Cutoff Values for Detecting Excellent Response to Therapy in Patients With Differentiated Thyroid Cancer

Jennifer A. Sipos, Joseph Aloi, Andrew Gianoukakis, Stephanie L. Lee, Joshua P. Klopper, Jacqueline T. Kung, Mark A. Lupo, David Morgenstern, Cristina Prat-Knoll, Andre Schuetzenmeister, Whitney S. Goldner

Research output: Contribution to journalArticlepeer-review

Abstract

Context: Serum thyroglobulin (Tg) is a biochemical marker for detecting persistent or recurrent differentiated thyroid carcinoma (DTC) post-thyroidectomy. Tg can indicate DTC before structural disease (SD) is visible with imaging procedures. Objective: This work aimed to evaluate the clinical performance of the Elecsys® Tg II assay at a Tg cutoff of 0.2 ng/mL for ruling out SD in adults with DTC after total/near-total thyroidectomy, with or without radioiodine ablation (RAI). Methods: Patients were enrolled into 2 cohorts: longitudinal (Tg assessed every 6 months over 2 years under thyroid-stimulating hormone [TSH] suppression therapy following thyroidectomy with or without RAI) and cross-sectional with confirmed SD (Tg assessed once >12 weeks after thyroidectomy). Analyses were performed for both cohorts combined and in the longitudinal cohort. Results: The study included 530 clinically evaluable samples, the majority (n = 424 samples) from patients who had not received RAI treatment. Following correction for SD prevalence (4.97% in the longitudinal cohort), an Elecsys Tg II cutoff of 0.2 ng/mL ruled out SD with a negative predictive value of 99.9% (95% CI, 99.5%-100%). The assay had excellent sensitivity (98.5%-100%) and acceptable specificity (53.4%-53.5%) for detecting SD (Tg ≥ 0.2 ng/mL) for both cohorts combined and in the longitudinal cohort, with similar findings in RAI-treated and non-RAI-treated subgroups. Conclusion: In this cohort of DTC patients post-thyroidectomy, a Tg cutoff of 0.2 ng/mL was highly effective for ruling out the presence of SD under TSH-suppressed conditions, including in patients who had not received RAI treatment.

Original languageEnglish (US)
Article numberbvad102
JournalJournal of the Endocrine Society
Volume7
Issue number9
DOIs
StatePublished - Sep 1 2023

Keywords

  • differentiated thyroid carcinoma
  • radioiodine
  • structural disease recurrence
  • thyroglobulin
  • thyroglobulin assay

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism

Fingerprint

Dive into the research topics of 'Thyroglobulin Cutoff Values for Detecting Excellent Response to Therapy in Patients With Differentiated Thyroid Cancer'. Together they form a unique fingerprint.

Cite this