Concentration of thyroglobulin and thyroglobulin-specific autoantibodies in patients with differentiated thyroid cancer after treatment with radioactive iodine 131

Abstract

Background: Measurement of serum thyroglobulin (Tg) is primarily used as a tumor marker in the postoperative management of patients with differentiated thyroid cancer (DTC), while thyroglobulin autoantibodies (TgAbs) are elevated in some patients as well. The aim f this study was to evaluate the concentrations of Tg and TgAbs in DTC patients 3 and 6 months after radioiodine therapy and to analyze whether the development and course of TgAbs is related to the clinical status of DTC patients or Tg levels before and after radioiodine therapy. Methods: Pre-treatment measurements were made in conditions of stimulation of Tg secretion with endogenous thyroid-stimulating hormone (TSH) (TSH>25 mIU/L), while the measurements after the treatment were obtained in conditions of suppression of Tg secretion (TSH<0.15 mIU/L). Results: Concentrations of Tg were decreased in the sera of all patients with DTC 6 months after radioiodine treatment, as well as the mean concentration TgAbs. Thyroglobulin autoantibody concentrations in sera of patients without metastasis were higher than in those with DTC metastases. Individual values of TgAbs in patients without metastases after the radioiodine treatment were decreased, increased, or unchanged. Conclusion: The development and course of TgAbs in DTC patients cannot be predicted by Tg levels before and after radioiodine therapy.