Relationship between thyroid cancer and thyroidautoantibodies in patients who had had had hadthyroidectomy: Retrospective evaluation of patientsdiagnosed between 2015-2023

SUMMARY RELATIONSHIP BETWEEN THYROID CANCER AND THYROID AUTOANTIBODIES IN PATIENTS WHO HAD HAD HAD HAD THYROIDECTOMY: RETROSPECTIVE EVALUATION OF PATIENTS DIAGNOSED BETWEEN 2015-2023 Objective:To explain the relationship between thyroid cancer and thyroid autoantibodies in patients who have undergone thyroidectomy, and to explain the disease marker relationship in early diagnosis and prognosis Materials and Methods:A total of 1418 patients who were followed up and underwent thyroidectomy in Karadeniz Technical University Farabi Hospital outpatient clinics and inpatient services between 2015 and 2023 were retrospectively examined. The demographic characteristics of the patients, laboratory data and clinical features at the time of diagnosis, and the selected diagnosis and treatment methods were examined retrospectively. Findings:In this retrospective study, 70.9% (n=1005) of 1418 patients who underwent thyroidectomy at Karadeniz Technical University Farabi Hospital between 2015 and 2023 had malignant pathology and 29.1% (n=416) had benign pathology. Among malignant cases, papillary carcinoma was the most common type (68.4%), while follicular nodular disease (18.5%) and Hashimoto's thyroiditis (6.3%) came to the fore in benign pathologies. TSI positivity was detected in 48.8%, TRAb in 11.5%, anti-Tg in 14.3% and anti-TPO in 23.3%. In 771 patients diagnosed with papillary carcinoma and variant analysis performed, the most common variants were determined as classical (45.9%), follicular (27.9%), oncocytic (11.7%) and miksted (11.4%) variants. While lymph node metastasis was detected in 16.4% and distant metastasis in 12.6% in classical variants, these rates were found to be 1% and 1%, respectively, in follicular variants, 1.4% and 2.6% in oncocytic variants, and 4.1% and 1.4% in miksted variants.Among patients with positive autoimmunity (positive for any of TSI, TRAb, Anti-Tg, Anti-TPO), 66.2% (n=215) had malignant disease. Of these patients, 64% (n=208) had papillary carcinoma, and 1.2% (n=4) had medullary carcinoma. 33.8% (n=110) of these patients had benign disease. Among them, 15.1% (n=49) had chronic lymphocytic thyroiditis-Hashimoto's thyroiditis, and 14.2% (n=46) had follicular nodular disease-nodular colloid goiter. 72.3% of patients with negative autoimmunity (n=790) were malignant, and malignancy diagnoses were statistically significantly lower in patients with positive autoimmunity. Results:Preoperative anti-Tg (17.1%) and anti-TPO (26.5%) positivity rates of patients with malignant pathology are higher than those with benign pathology, except Hashimoto's thyroiditis (p=0.002 and p=0.013). There was no difference between postoperative anti-Tg (12.4% vs. 7.0%) and anti-TPO (14.2% vs. 10.8%) positivity rates (p=0.055 and p=0.491). These findings show that preoperative autoantibody positivity is more prominent in malignant pathologies. Key Words:Thyroid Antibodies, Thyroid Cancer, Anti-Thyroid Peroxidase Antibody, Anti-Thyroglobulin Antibody, Papillary Thyroid Cancer.