Investigating Antithyroglobulin Antibody As a Prognostic Marker for Differentiated Thyroid Cancer: A Meta-Analysis and Systematic Review

Background: Serum thyroglobulin (Tg) is used in the follow-up of patients with differentiated thyroid cancers (DTC), but the presence of antithyroglobulin antibodies (TgAbs) makes Tg measurements unreliable. TgAb decline after total thyroidectomy and persistent/increasing levels may indicate cancer persistence/recurrence. Hence, we aimed to determine whether TgAb might be a reliable prognostic marker for DTC. Methods: We conducted a meta-analysis and systematic review. A comprehensive literature search was performed to identify studies of patients with DTC with known TgAb status and prognostic outcomes in five databases (Medline, Embase, PubMed, Google Scholar, and Scopus). We used a random-effects model to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs) for TgAb status and its association with DTC prognosis. Results: After analysis of 34 studies, we found that TgAb+ patients have a higher risk of lymph node metastasis (OR = 1.18 [CI 1.47-2.25]) and cancer persistence/recurrence (OR = 2.78 [CI 1.55-4.98]) than TgAb- patients. However, no significant differences in mean/median tumor size, risk of extrathyroidal extension, tumor multifocality, and cancer mortality were found between the two groups. In a comparison of TgAb trends, patients with persistent/increasing TgAb levels were found to have a higher risk of cancer persistence/recurrence (OR = 9.90 [CI 4.36-22.50]) and cancer mortality (OR = 15.18 [CI 2.99-77]) than patients with decreasing TgAb levels. Conclusions: TgAb positivity and persistent/increasing trends were associated with compromised DTC prognosis. These results suggest that TgAb may be used as a prognostic marker in the follow-up of patients with DTC.