Evaluation of the Bethesda System and the ACR TIRADS in an Endemic Goiter Region.

Background: Various factors can affect incidence of thyroid disorders and disease profiles may show abrupt changes in endemic goitrous areas. In this study, it was aimed to analyze the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) and the Bethesda System for Reporting Thyroid Cytopathology (BSRTC) in terms of risk of malignancy and general recommendations in an endemic goiter region (EGR).

Methods: In this retrospective study, a total of 500 patients who had thyroidectomy following thyroid fine needle aspiration biopsy were enrolled. For the assessment of thyroid cytology, BSRTC was used and for the evaluation of ultrasound features of thyroid nodules, ACR TIRADS lexicon was adopted. For the assessment of thyroid cytology, Bethesda classification was used and for the evaluation of ultrasound features of thyroid nodules, ACR TIRADS lexicon was adopted.

Results: In the EGR setting, benign category of BSRTC had a cancer risk of 6.2% which was two times more than the 2017 BSRTC revision reported. Nodules 10-14.9 mm in diameter had nearly 4 times higher malignancy risk than nodules >15 mm. In this group of patients, the risk of malignancy for TIRADS level 1, 2, 3, 4 and 5 was 1.16%, 2.94%, 7%, 45.64% and 94.44%, respectively. The malignancy rates for Bethesda system category I, II, III, IV, V and VI were as follows: 14.43%, 6.2%, 19.05%, 36.73%, 75.68% and 100%.

Conclusions: There are slight differences between the common set of standards and this study results regarding risk of malignancy. This brings up the question whether there is need for revision for the use of categories and the appropriate management in endemic goiter regions.