Background: The clinical value of antithyroglobulin antibodies (TgAb) as a tumor marker for differentiated thyroid cancer (DTC) is still controversial. Materials & methods: We studied 110 TgAb positive DTC patients who underwent total thyroidectomy and 131I therapies. Multivariate logistic regression was conducted to analyze the association between prognostic factors and disease outcomes. Results & conclusion: Pre-ablation TgAb levels and the changes of TgAb in 6-12 months after the first 131I therapy were risk factors for disease outcome in patients younger than 55, while extrathyroid extension was a risk factor in patients older than 55. The median TgAb half-life was 7.7 months and the median time for TgAb positivity to become negative was 15.8 months. The dynamics of TgAb within the first year after remnant ablation could predict disease outcome for DTC patients.
Keywords: 131I therapy; antithyroglobulin antibody; differentiated thyroid cancer; half-life; thyroglobulin.