Inconclusive cytology results of fine-needle aspiration for thyroid nodules: the importance of strict guideline implementation

Purpose This study investigated whether strict adherence to the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) biopsy indications could reduce inconclusive cytology results and evaluated associated clinical factors. Methods This retrospective study included 2,440 nodules from 2,256 pati...

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Main Authors: Sangwoo Cho, Kyunghwa Han, Jung Hyun Yoon, Vivian Youngjean Park, Miribi Rho, Jiyoung Yoon, Jin Young Kwak
Format: Article
Language:English
Published: Korean Society of Ultrasound in Medicine 2025-07-01
Series:Ultrasonography
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Online Access:http://www.e-ultrasonography.org/upload/usg-24216.pdf
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Summary:Purpose This study investigated whether strict adherence to the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) biopsy indications could reduce inconclusive cytology results and evaluated associated clinical factors. Methods This retrospective study included 2,440 nodules from 2,256 patients who underwent initial fine-needle aspiration (FNA) for thyroid nodules from January to December 2022. Inconclusive specimens were defined as Bethesda categories I and III, while conclusive specimens comprised Bethesda categories II, IV, V, and VI. Nodules smaller than the K-TIRADS biopsy threshold were considered FNA not-indicated nodules. Clinical factors included patient age, sex, ultrasound features, nodule size, number of needle passes, and operator experience. Univariate and multivariate logistic regression analyses were performed to assess the associations between clinical factors and inconclusive results. Results Among 2,440 nodules, 900 yielded initial inconclusive biopsy results, while 1,540 provided conclusive results. Independent predictors of inconclusive biopsy results included FNA not-indicated nodules, nodules sized 0 to 5 mm, operator experience of less than 1 year, older age, and K-TIRADS category 4 (P<0.001, P=0.006, P=0.003, P=0.001, and P<0.001, respectively). Among K-TIRADS category 4 nodules, the presence of suspicious ultrasound characteristics was negatively associated with inconclusive biopsy results (P=0.004). Conclusion FNA not-indicated nodules, nodule size of 0 to 5 mm, operator experience of less than 1 year, older age, and K-TIRADS category 4 were factors associated with inconclusive biopsy results. Strict adherence to the K-TIRADS biopsy indications may reduce inconclusive cytology results.
ISSN:2288-5943