Endocrine https://doi.org/10.1007/s12020-018-1620-6 ENDOCRINE METHODS AND TECHNIQUES Does the ACR TI-RADS scoring allow us to safely avoid unnecessary thyroid biopsy? single center analysis in a large cohort Fatos Dilan Koseoglu Atilla 1 ● Basak Ozgen Saydam 2 ● Nihat Ali Erarslan 3 ● Ayse Gulden Diniz Unlu 4 ● Hamiyet Yilmaz Yasar 5 ● Muhammet Ozer 6 ● Baris Akinci 2 Received: 3 January 2018 / Accepted: 26 April 2018 © Springer Science+Business Media, LLC, part of Springer Nature 2018 Abstract Introduction The American College of Radiology (ACR) has recently proposed a guideline that recommends clinicians to perform thyroid fine-needle aspiration biopsy (FNAB) on the basis of ultrasound features. In this study, we focused on nodules for which no biopsy is recommended by the ACR Thyroid Imaging, Reporting and Data System (TI-RADS) guideline. Subjects and methods Two-thousand eight-hundred and forty-seven consecutive patients with thyroid nodules who underwent FNAB according to the 2009 American Thyroid Association (ATA) guideline were included. The nodules were re-classified according to the ACR TI-RADS guideline as benign (TR1), not suspicious (TR2), mildly suspicious (TR3), moderately suspicious (TR4) and highly suspicious (TR5). The TR3 category was stratified into two subcategories as regard to the nodule size (TR3; <25 mm and TR3; ≥25 mm). Results Two-hundred and thirty-three (8.2%) patients with non-diagnostic FNABs were excluded. When the TR2 and TR3; <25 mm categories were merged, FNAB was suggestive of thyroid cancer in 17 of 1382 patients (1.2%). FNAB revealed Bethesda IV–VI in 5 of 273 patients with the TR3; ≥25 mm category (1.8%), in 61 of 896 patients with the TR4 category (6.8%), and in 18 of 63 of patients with the TR5 category (28.6%). The ACR TI-RADS scoring was 98.8% (95% CI: 98 to 99.3) specific for identification of a benign nodule. Conclusion Our data suggest that ACR TI-RADS scoring is an applicable and potentially cost-effective approach to determine thyroid nodules to be biopsied, although a small proportion of thyroid cancers would be missed. Keywords Thyroid nodules ● Fine-needle aspiration biopsy ● Thyroid cancer ● Thyroid ultrasound Introduction Thyroid nodules are a common clinical problem and although the majority are benign, approximately 5% can harbor malignancy mainly with differentiated thyroid cancer [1]. With the increased utilization of ultrasound (US) for evaluation of non-thyroid lesions of the neck, the inci- dental finding of thyroid nodules has dramatically increased [2, 3]. The American College of Radiology (ACR)’s recently implemented guideline endorses a clinical approach for the management of patients with thyroid nodules that are driven by US findings, which helps clinicians to decide whether a fine-needle aspiration biopsy (FNAB) is required. In this approach, nodules with overall ACR Thyroid Imaging, Reporting and Data System (TI-RADS) score <3 are clas- sified as benign (TR1)/ non-suspicious (TR2) and no biopsy is recommended. Also, no biopsy is recommended for mildly suspicious nodules with an ACR TI-RADS score These authors contributed equally: Fatos Dilan Koseoglu Atilla, Basak Ozgen Saydam. * Basak Ozgen Saydam basakozgen@gmail.com 1 Department of Internal Medicine, Tepecik Training and Research Hospital, 35180, Izmir, Turkey 2 Division of Endocrinology and Metabolism, Dokuz Eylul University Faculty of Medicine, 35340, Izmir, Turkey 3 Department of Radiology, Tepecik Training and Research Hospital, 35180, Izmir, Turkey 4 Department of Pathology, Tepecik Training and Research Hospital, 35180, Izmir, Turkey 5 Division of Endocrinology and Metabolism, Tepecik Training and Research Hospital, 35180, Izmir, Turkey 6 Department of Internal Medicine, Dokuz Eylul University Faculty of Medicine, 35340, Izmir, Turkey 1234567890();,: 1234567890();,: