SAT528 Evaluation of Fine Needle Aspiration Biopsy Results in Patients with History of Thyroid Surgery for Benign Thyroid Disease

Disclosure: A.S. Can: None. J. Naran: None. Objective: We aimed to compare our thyroid fine needle aspiration (FNA) biopsy results in patients with history of thyroid surgery for benign thyroid disease and in patients without history of thyroid surgery. Material and Method: FNAs were performed between January 2016 and December 2020. The demographic data and outcomes were reviewed retrospectively. The results were presented per nodule, not per patient. FNA was performed on two groups: Group 1: nodules with history of thyroid surgery for benign thyroid disease, and Group 2: nodules without history of thyroid surgery. FNA results were categorized as malignant, benign, indeterminate, and unsatisfactory. FNAs were performed under ultrasound guidance. Results: 711 thyroid nodules underwent ultrasound guided FNA. 18 FNAs were performed on nodules diagnosed in patients who had history of thyroid surgery for benign thyroid disease (Group 1). Average age and standard deviation (SD) of Group 1 were 63±10 years. Average maximum size of nodules in Group 1 was 20±12 mm and average volume was 5.4±13.0 mL. Group 1 nodules had surgery on average 18±10 years ago. Thirteen nodules had hemithyroidectomy, three subtotal thyroidectomy and two nodule removal only. 693 FNAs were performed on nodules diagnosed in patients without history of thyroid surgery (Group 2). Average age and SD of Group 2 patients were 58±14 years. Average maximum size of nodules in Group 2 was 21±11 mm and average volume was 4.7±9.7 mL. FNA results in Group 1 versus Group 2 nodules were as follows: malignant 0% versus 3% (n=0 versus n=22), benign 72% versus 68% (n=13 versus n=470), indeterminate 6% versus 10% (n=1 versus n=70), unsatisfactory 22% versus 19 % (n=4 versus n=131), Chi-Square= 1.08, degrees of freedom= 3, p= 0.78. There was no statistical difference between groups in biopsy results. The chi-square statistic may not be reliable because two of the expected frequencies were less than 5. Conclusions: We did not observe any malignancy in patients with thyroid nodules who had history of thyroid surgery for benign thyroid disease. FNA performed similarly well whether there was history of thyroid surgery for benign thyroid disease or not. Further studies on larger group of patients with history of thyroid surgery for benign disease can be considered to confirm our findings. Presentation Date: Saturday, June 17, 2023