Archives of Endocrinology and Metabolism (Jul 2021)

Thyroglobulin/thyrotropin ratio for predicting long-term response in differentiated thyroid carcinoma: a retrospective study

  • Adriano Francisco De Marchi Junior,
  • Ana Bárbara Trizzotti de Macedo,
  • Carlos Segundo Paiva Soares,
  • Fernanda Bolfi,
  • Mariana Riello Gomes Iessi,
  • Cristiano Claudino de Oliveira,
  • Katia Hiromoto Koga,
  • Sonia Marta Moriguchi,
  • José Vicente Tagliarini,
  • Gláucia Maria Ferreira da Silva Mazeto

DOI
https://doi.org/10.20945/2359-3997000000387
Journal volume & issue
Vol. 65, no. 4
pp. 428 – 435

Abstract

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ABSTRACT Objective: Thyrotropin-stimulated thyroglobulin (STg) after total thyroidectomy is a prognosis marker for differentiated thyroid carcinoma (DTC). As Tg level is influenced by thyrotropin (TSH), perhaps the STg/TSH ratio is also a prognosis marker for these tumours. We aimed to compare STg/TSH ratio and first STg level in differentiated thyroid carcinoma patients for their ability to predict the long-term response to initial treatment. Subjects and methods: This retrospective study evaluated data from 181 DTC patients for first (1st) STg and STg/TSH ratio, at 1-3 months post-total thyroidectomy and before iodine-131 therapy, according to response to initial therapy [Excellent/Indeterminate or Incomplete (Biochemical/Structural)] observed at final evaluation, and with the survival time with excellent/indeterminate response. Results: Cases with incomplete response presented higher STg level [225.13 ± 585.26 ng/mL versus (vs) 20.4 ± 192.9 ng/mL; p < 0.001] and STg/TSH ratio (3.01 ± 7.8 vs 0.27 ± 2.58; p < 0.001). Cutoffs of 5 ng/mL for STg and 0.085 for STg/TSH displayed sensitivities of 76.7% and 76.9%, and specificities of 79.2% and 82.6%, respectively, in predicting response to therapy. Values below these cutoffs were associated with longer survival time in excellent/indeterminate response (140.4 vs 15.9 and 144.6 vs 15.9 months, respectively). Conclusion: STg/TSH ratio has a similar performance to the 1st STg in predicting long-term response to initial therapy.

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