Thyroglobulin levels before radioactive iodine therapy and dynamic risk stratification after 1 year in patients with differentiated thyroid cancer

• Autor(a) principal: Bandeira,Leonardo
• Data de Publicação: 2017
• Outros Autores: Padovani,Rosália do Prado, Ticly,Ana Luiza, Cury,Adriano Namo, Scalissi,Nilza Maria, Marone,Marília Martins Silveira, Ferraz,Carolina
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Arquivos de Endocrinologia e Metabolismo (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2359-39972017000600590
• topic: Dynamic risk stratification; radioactive iodine therapy; thyroglobulin; thyroid cancer

ABSTRACT Objectives: We sought to assess the relationship between stimulated thyroglobulin (sTg) before radioactive iodine therapy (RIT), and the dynamic risk stratification 1 year after treatment, and to establish the utility of the sTg as a predictor of response to therapy in these patients. A retrospective chart review of patients with differentiated thyroid cancer (DTC) who underwent RIT after surgery and were followed for at least 1 year, was carried out. Subjects and methods: Patients were classified according to the dynamic risk stratification 1 year after initial treatment. The sTg values before RIT were compared among the groups. ROC curve analysis was performed. Results: Fifty-six patients were enrolled (mean age 44.7 ± 14.4 years, 80.7% had papillary carcinoma). Patients with excellent response had sTg = 2.1 ± 3.3 ng/mL, those with indeterminate response had sTg = 8.2 ± 9.2 ng/mL and those with incomplete response had sTg = 22.4 ± 28.3 ng/mL before RIT (p = 0.01). There was a difference in sTg between excellent and incomplete response groups (p = 0.009) while no difference was found between indeterminate and either excellent or incomplete groups. The ROC curve showed an area under the curve of 0.779 assuming a sTg value of 3.75 ng/mL. Conclusion: Our study results suggest that the higher the sTg before RIT, the greater the likelihood of an incomplete response to initial treatment. A sTg cut-off of 3.75 ng/mL was found to be a good predictor of response to initial treatment in patients with DTC.