The clinical value of repeat ultrasound-guided fine-needle aspiration biopsy in the management of Bethesda Category III thyroid nodules

Objective: This study aimed to evaluate the clinical value of repeat fine-needle aspiration biopsy (rFNAB) for thyroid nodules initially classified as Bethesda Category III, to explore the optimal timing for repeat biopsy, and to optimize the biopsy strategy by integrating ultrasonographic characteristics. Methods: We retrospectively analyzed the clinical data of 109 patients (114 nodules) who underwent rFNAB at our hospital from December 2020 to December 2025, including 87 females and 22 males. Based on rFNAB results, the nodules were divided into a definitive diagnosis group (93 nodules) and a non-definitive diagnosis group (21 nodules). The definitive diagnosis group was further subdivided into a malignant group (62 nodules, Bethesda V/VI) and a benign group (31 nodules, Bethesda II). We recorded biopsy results, intervals between biopsies, postoperative pathological findings, and ultrasonographic features. Statistical differences between groups were analyzed. Statistical methods included the χ² test, Fisher's exact test, binary logistic regression analysis, and ROC curve analysis. Results: Among the 114 Bethesda Category III nodules, 93 (81.6%) obtained a definitive diagnosis through rFNAB, including 62 malignant (66.7%) and 31 benign (33.3%) nodules; 21 nodules (18.4%) remained non-diagnostic. Forty-seven patients with malignant rFNAB results underwent surgical treatment, including 9 (19.1%) in the