SAT-343 The Role of Preoperative Titers of Thyroglobulin Antibodies in Thyroid Cancer: Data from a Multicentric International Collaboration

Abstract Disclosure: R.D. Paparodis: None. E. Karvounis: None. G. Simeakis: None. I. Androulakis: None. D.P. Askitis: None. S. Livadas: None. A. Rizoulis: None. V. Papanikos: None. N.S. Mastronikolis: None. D. Zianni: None. C. Massouras: None. I. Perogamvros: None. A. Boniakos: None. N.G. Angelopoulos: None. D. Bantouna: None. A. Kapezanou: None. O. Aporelli: None. S. Imam: None. J.C. Jaume: None. Introduction: Cancer modulates the tumor immune microenvironment (TIME) in multiple organs promoting tumorigenesis. In thyroid glands, the presence of some thyroid lymphocytic infiltrates seems to increase the likelihood of thyroid cancer (TC). High titers of TPO antibodies have shown a protective effect against the development of thyroid cancer. On the other hand, thyroglobulin antibodies (Tg-Abs) are an integral part of thyroid autoimmunity work up, but their role on TC development/progression remains unclear. We designed the present study to shed light on that question. Methods: We performed a retrospective review of data from patients undergoing thyroidectomy (Tx) in 2 centers in the US and 13 in Greece, over 10 years. We collected data on age, gender, BMI, preoperative TSH, Tg-Abs and surgical pathology. We compared the incidence of TC among patients with high (Tg-Abs+ ≥30IU/L) and low titers (Tg-Abs- ≤30IU/L), as well as the features of tumor aggressiveness between the two groups. Results: We reviewed n=9643 Tx, and included n=2870 patients; mean BMI was 27.3±5.5Kg/m2, age 47.0±14.5 years and n=743 (25.9%) were males. Mean TSH was 2.11±5.09IU/L, and Tg-Abs were 96.0±614.6IU/L. Tg-Abs+ were found in n=638 (22.2%) patients. Overall n=1286 had benign histology and n=1587 had TC: papillary (PTC) n=1487, follicular (FTC) n=35 Hürthle cell (HCC) n=23, medullary n=30, anaplastic (ATC) n=1, poorly differentiated thyroid cancer (PDTC) n=7, other n=3, lymphoma n=1. Mean tumor size was 1.5±2.0cm, tumor foci were 1.8±1.8, n=26 (1.6%) had gross and n=249 (15.7%) had microscopic extrathyroidal extension (ETE), n=212 (13.4%) had capsular invasion (CI), n=391 (24.6%) had lymph nodes (LNs) involvement and n=24 (1.5%) developed distant metastases. Overall cancer incidence by pathology did not differ by Tg-Abs status. Distant metastases development was similar between groups as well (OR 0.98, p>0.05). In Tg-Abs+ patients, tumors were larger (1.8 vs. 1.4cm), had more LN involvement (OR 2.2), ETE was more common (OR 1.25) as did capsular invasion (OR 1.20), but they were more rarely of histology other than PTC (OR 0.49) (p<0.05). Conclusions: Unlike TPO antibodies, Tg-Abs do not appear protective of TC, but their rise seems to signal an immune response to the expansion of TC beyond the thyroid gland, especially with regard to PTC sub-type. Tg-Abs titers should be taken into consideration when evaluating patients with thyroid nodules at least for prognostic assessment. Presentation: Saturday, July 12, 2025