Endocrine Abstracts

Backgroud: Thyroid cancer, particularly papillary thyroid carcinoma (PTC), is globally on the rise, driven by increased incidental findings. PTC treatment boasts a commendable 93% 10-year survival rate, yet up to 28% of patients experience locoregional recurrences. Serum thyroglobulin (Tg) serves as a vital marker in post-operative surveillance for differentiated thyroid cancer (DTC). Anti-thyroglobulin antibodies (TgAb) play a crucial role in Tg interpretation, with their interference requiring reliable detection as per American Thyroid Association guidelines. Elevated TgAb levels, more prevalent in recent DTC cases, correlate with increased risks of persistence or recurrence, forming the focus of this study’s analysis.

Method: This retrospective study included 15,620 patients from Gangnam Severance Hospital Thyroid Cancer Center who underwent bilateral thyroidectomy for thyroid cancer from March 2004 to December 2022. After exclusions for missing postoperative TgAb results and other carcinoma types, 4434 cases of papillary thyroid carcinoma (PTC) were retrospectively reviewed. Preoperative evaluations involved thyroid ultrasound and fine needle aspiration biopsy for suspicious nodules. TgAb tests, initiated 2 days post-surgery and repeated annually, were stratified into quartiles, and logistic regression analysis revealed a significant association between TgAb levels and PTC recurrence.

Results: The study group comprised 4434 thyroid cancer patients, with 775 males and 3659 females, and a median age of 46 ± 11.68. In Group 1 (TgAb level less than 20), consisting of 3640 patients, 81.2% were female. Tumor size and cancer recurrence rates increased significantly with higher TgAb levels in each group (P < 0.001). The proportion of females was consistently higher across all TgAb groups. Extrathyroidal extension did not exhibit a similar trend. The correlation analysis illustrated a consistent pattern: increasing TgAb levels corresponded to elevated odds ratios and probabilities of papillary thyroid carcinoma recurrence.

Conslusion: In patients who underwent total thyroidectomy for papillary thyroid cancer, serum TgAb levels may be useful in predicting patient recurrence. Previously, the prognosis of PTC patients was considered by dividing them into TgAb positive or negative. Now, by taking advantage of the fact that the higher the serum TgAb level, the higher the recurrence rate, this value alone can be used as a new prognostic indicator regardless of the time of TgAb testing after surgery.