Clinical Significance of Circulating Anti-Thyroglobulin Autoantibodies After First Remnant Ablation in Patients with Differentiated Thyroid Cancer

Objectives Clinical significance of circulating anti-thyroglobulin antibody (TgAb) titers during the follow-up of differenciated thyroid cancer(DTC) was not well demonstrated. To shed light on this issue, we retrospectively examined a large series of DTC patients with and without positive TgAb.

Methods Data of 102 TgAb-positive DTC patients (study cohort) were retrospectively collected. All the patients had undergone near-total thyroidectomy with radioiodine remnant ablation. Their tumor characteristics and final outcome were compared with 534 TgAb-negative DTC patients with similar demographic characteristics. The mean ablation courses of each group were also counted.

Results At baseline, the study cohort (mean age 38.5 years, range 8-69 years; 91.2% female) had a significantly higher prevalence of high-risk patients (11.2% vs. 3.7%, p < 0.05) than TgAb-negative controls. Study cohort patients were also more likely than controls to have persistent disease at the 1-year visit (40.2% vs. 23.5%, p = 0.001) and more 131I therapy courses (mean 2.3 vs 1.2, P<0.05). At the final follow-up visit, the percentage of patients with either persistent or recurrent disease in the two cohorts was significantly different (16.2% of TgAb-positive patients vs. 5.1% in the TgAb-negative group, p < 0.05).

Conclusions DTC patients with positive serum TgAb titer after first thyroid remnant ablation are more likely to have persistent/recurrent disease than those who are consistently TgAb-negative. They are also likely to have more 131I therapy courses.