title: Accuracy of international ultrasound risk stratification systems in thyroid lesions cytologically classified as indeterminate.
abstract: BACKGROUND
  Eminent international societies have published their thyroid ultrasound risk stratification system (US-RSS) to give a friendly tool for thyroidologists. In particular, American Thyroid Association (ATA), American Association Clinical Endocrinologists/American College of Endocrinologists and Associazione Medici Endocrinologi (AACE/ACE/AME), British Thyroid Association (BTA), and Thyroid Imaging Reporting and Data System (TIRADS) are often adopted for clinical practice. The reliability of these US-RSS has not been evaluated in discriminating cancers from benignancy in nodules with indeterminate FNA.
  
  
  METHODS
  Indeterminate thyroid lesions were searched in our database and only those with histology were finally included. The matching of US and histologic data of nodule's location and size were verified. All US images and clips were re-evaluated and nodules classified according to the above US-RSS.
  
  
  RESULTS
  A series of 101 indeterminate lesions, diagnosed by FNA were included (mean size 2.4 cm) and a 21% of cancers was found at histology. When all lesions were classified by US-RSS, poor accuracy (up to 54%) and specificity (up to 19%) were recorded. Highest sensitivity (91%) and NPV (94%) was obtained by BTA. Of relevance, the rate of nodules with indeterminate US risk recorded by BTA was significantly lower than the other (P < 0.001). At nodule's size analysis, cancers had significantly higher estimated volume (P < 0.05). When we considered the size thresholds proposed by guidelines, ATA system reached the highest sensitivity in detecting cancers (95%).
  
  
  CONCLUSIONS
  Even if international US-RSS have suboptimal accuracy in indeterminate thyroid nodules, high sensitivity can be obtained using ATA system with specific dimensional cut-offs. Diagn. Cytopathol. 2017;45:113-117. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Nuclear Medicine and Thyroid Centre, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: Trimboli
authors.affiliation: Pathology Institute of Locarno, Locarno, Switzerland.
authors.forename: Franco
authors.identifier: http://orcid.org/0000-0002-4244-1109
authors.initials: F
authors.lastname: Fulciniti
authors.affiliation: Department of Nuclear Medicine and Thyroid Centre, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
authors.forename: Valentina
authors.initials: V
authors.lastname: Zilioli
authors.affiliation: Department of Nuclear Medicine and Thyroid Centre, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
authors.forename: Luca
authors.initials: L
authors.lastname: Ceriani
authors.affiliation: Department of Nuclear Medicine and Thyroid Centre, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland.
authors.forename: Luca
authors.initials: L
authors.lastname: Giovanella
mesh_terms: D000068598:Data Accuracy; D004704:Endocrinology / Q000458:organization & administration; D006801:Humans; D017410:Practice Guidelines as Topic; D012955:Societies, Medical; D013964:Thyroid Neoplasms / Q000145:classification / Q000000981:diagnostic imaging* / Q000473:pathology; D014463:Ultrasonography / Q000592:standards*; D006113:United Kingdom; D014481:United States
keywords: fine needle aspiration cytology (FNA); indeterminate; thyroid; ultrasonography