The Relationship Between Serum Levels of Thyroglobulin Antibody and the Risk of Recurrence in Patients With Differentiated Thyroid Cancer.

[OBJECTIVE] Thyroid Autoantibodies (TgAbs) are associated with autoimmune thyroid disorders and are also used in thyroid cancer follow-up to monitor for recurrence of disease. This study aimed to explore the potential utility of TgAbs as a surrogate tumor marker and examine the relationship between fluctuations in TgAbs levels and disease recurrence in patients with Differentiated Thyroid Cancer (DTC).

[METHODS] This cohort study was conducted on a sample of 97 patients who underwent thyroidectomy for differentiated thyroid cancer (DTC) between the years 2017 and 2021. Following surgery (with or without lymph node dissection), levothyroxine therapy and 131 iodine were prescribed (as necessary). Regular laboratory evaluations were conducted, which involved measuring Tg and TgAb at 3 and 6 months postoperatively. Patients were classified based on recurrence rate and different levels of TgAb, and ROC analysis was applied. All data were analyzed with SPSS24, and a p-value < 0.05 was considered statistically significant.

[RESULTS] For low-risk patients, TgAb trends over time showed an increase at 6 months, while for high-risk patients, TgAb levels continuously rose starting from 3 months. Although TgAb levels above the functional sensitivity threshold did not predict recurrence overall, changes in TgAb levels at 6 months compared to 3 months after surgery were indicative of recurrence.

[CONCLUSION] In the entire population, having TgAb levels higher than the functional sensitivity threshold had no risk of various relapses. However, changes in TgAb serum levels at 6 months after surgery, compared to 3 months after surgery, can serve as an indication of tumor recurrence.