title: Results of retrospective classification of thyroid FNAs according to the Bethesda system: would this have improved accuracy?
abstract: OBJECTIVE
  To retrospectively reclassify the results of fine needle aspiration (FNA) cytology at our institution according to the Bethesda system for reporting thyroid cytopathology (TBSRTC), and to determine whether the introduction of the new classification system would have influenced the diagnostic accuracy compared with our existing system in which suspicious/indeterminate categories (categories III-IV) are managed according to clinical findings and cytopathologists' recommendations.
  
  
  METHODS
  FNAs performed under ultrasound guidance between 2001 and 2012, and subsequently verified by histology or repeat FNA and follow-up, were reviewed and retrospectively reclassified according to TBSRTC.
  
  
  RESULTS
  Among a total of 1310 histologically verified FNAs, the positive predictive values (%) for malignancy and neoplasia (carcinoma + follicular adenomas) for category I-VI according to the TBSRTC were 5.7/11.3, 2.6/5.5, 14.4/34.2, 23.6/55.0, 57.0/64.5 and 92.2/94.2, respectively. Although all the categories predict malignancy closely, the difference in malignancy rate between categories III and IV was not statistically significant; however, the difference in total neoplasia rate reached statistical significance. When patients with cytological and clinical follow-up were included, the malignancy rated dropped in category I to 2.4%, whereas, in category III, it remained at 13%. Repeat FNA instead of direct surgery spared half of the patients from surgery. The cytopathologists' recommendations for histological verification in category III were associated with an insignificant increase in malignancy rate, but the total neoplasia rate reached 57.5%.
  
  
  CONCLUSIONS
  At our institution, the application of the TBSRTC did not improve the diagnostic accuracy for the detection of malignancy compared with current practice. In selected cases with cytological results falling into category III (according to clinical data and cytopathologists' opinions), direct lobectomy seems to be justified.
authors: Department of Clinical Endocrinology, The Institute of Endocrinology, Prague, Czech Republic.
authors: L
authors: L
authors: Srbova
authors: 4th Dept. of Internal Medicine, University Hospital and Faculty of Medicine, Hradec Kralove, Czech Republic.
authors: F
authors: F
authors: Gabalec
authors: Fingerland's Department of Pathology, University Hospital and Faculty of Medicine, Hradec Kralove, Czech Republic.
authors: A
authors: A
authors: Ryska
authors: 4th Dept. of Internal Medicine, University Hospital and Faculty of Medicine, Hradec Kralove, Czech Republic.
authors: J
authors: J
authors: Cap
mesh_terms: D044963:Biopsy, Fine-Needle / Q000379:methods; D003581:Cytodiagnosis / Q000379:methods; D006801:Humans; D012189:Retrospective Studies; D013961:Thyroid Gland / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000473:pathology
keywords: TBSRTC; cytology; fine needle aspiration; follicular adenoma; the Bethesda system for reporting thyroid cytopathology; thyroid carcinoma