# Evaluation of the Necessity of Repeat Biopsy in Patients with Thyroid Nodules Classified as Atypia of Undetermined Significance (AUS) Based on Fine-Needle Aspiration Biopsy Results

## TL;DR

This study examines whether repeat biopsies are needed for thyroid nodules classified as AUS, finding similar cancer rates after one or two biopsies.

## Contribution

The study provides evidence that early-stage cancers are more common after a single biopsy, suggesting current guidelines may need revision.

## Key findings

- Malignancy rates were similar after first or second biopsies (71.2% vs. 67.7%).
- Early-stage tumors were more frequent after the first biopsy (63.8% vs. 37.2%).
- EU-TIRADS classifications showed no significant differences between groups.

## Abstract

Background and Objectives: The necessity of repeat fine-needle aspiration biopsy (FNAB) in nodules diagnosed as atypia of undetermined significance (AUS) remains debated. This study evaluates the role of a second FNAB in surgical decision making. Materials and Methods: A retrospective analysis was conducted on 131 patients (105 females and 26 males) who underwent surgery following an AUS diagnosis between 2020 and 2024. Patients were grouped based on whether surgery was performed after the first or second FNAB. Demographics, pathology, and ultrasound findings were compared. Results: Of the patients, 66 (50.7%) underwent surgery after the first FNAB and 65 (50.3%) after a second AUS diagnosis. Malignancy was detected in 47 out of 66 (71.2%) patients in the single biopsy group and in 44 out of 65 (67.7%) patients in the repeat biopsy group (p = 0.804). T1a tumors were more frequent in the first FNAB group (63.8% vs. 37.2%, p = 0.021). The EU-TIRADS classifications showed no significant differences. Conclusions: The malignancy rate observed (71.2%) exceeds reported rates in the literature, suggesting regional variability. Early-stage cancers were more frequent in patients operated on after the first FNAB, questioning the necessity of repeat biopsy and indicating a potential need to revise current guidelines.