Comparison of the Bethesda system classification and postoperative cytology of thyroid nodules: A single center experience

Abstract

Objective: Recent American Thyroid Association Guideline emphasizes that identifying the institutional malignancy risks for each Bethesda category is mandatory to achieve more accurate preoperative diagnosis in thyroid nodules. Aim of this study is to compare the preoperative fine needle aspiration biopsy (FNAB) and postoperative pathology results in a single institution in the era of the Bethesda System for Reporting thyroid Cytology (TBSRTC). Methods: The data of the patients who underwent FNAB and thyroidectomy between 2012 and 2018 were collected retrospectively. Patients who had available TBSRTC classification were included in the study. The malignancy risk of each TBSRTC classification was calculated. Results: One-hundred and forty-five patients were included. The mean age was 45.9±13.6. Preoperative FNAB categorization was TBSRTC I in 3 (2.1%) patients, TBSRTC II in 47 (32.4%) patients, TBSRTC III 16 (11%) patients, TBSRTC IV in 14 (9.7%) patients, TBSRTC V in 29 (20%) and VI in 36 (24.8%) patients. Postoperative pathology revealed malignancy in 66 (45.5%) of the patients. The malignancy risk was 33.3% in TBSRTC I, 4.3% in TBSRTC II, 31.3% in TBSRTC III, 42.9% in TBSRTC IV, 62.1% in TBSRTC V and 94.4% in TBSRTC VI categories. Conclusion: Our results were conformable with the malignancy risks reported by TBSRTC. Larger studies should be performed to validate and endorse nationwide standardization of the Bethesda system.