Concordance between the TIRADS ultrasound criteria and the BETHESDA cytology criteria on the nontoxic thyroid nodule

BACKGROUND Thyroid nodule is a common disorder of the thyroid. Despite their benign nature, they can be associated with multiple pathologic conditions, including thyroid cancer. METHODS This cross-sectional study determined the concordance of Ultrasound (TIRADS criteria) and Fine Needle Aspiration Biopsy (FNA-BETHESDA system) in the assessment of the nontoxic thyroid nodule. A total of 180 subjects 18 years old or older underwent the two diagnostic tests and their results were compared using kappa index. RESULTS Participants were mostly women, with average age of 57 years. The frequency of BETHESDA II was 65/180 versus 45/180 in TIRADS 2. In contrast, the highest frequency in category 4-IV was 62/180 for TIRADS 4 versus 41/180 for BETHESDA IV. The highest concordance was found among the category 2-II classification. The observed agreement was 87.2% with a linear weighted kappa of 0.69 (95% CI: 0.59-0.79). The heterogeneity analysis showed a trend towards a higher weighted kappa value in nodules ≥4 cm in males and individuals aged ≥50 years, with accelerated nodular growth, binding to adjacent structures, vocal folds paralysis, urban origin, and a history of head and neck radiation therapy. CONCLUSIONS The TIRADS criteria has a good concordance with the Bethesda system. The ultrasound findings of benign pathology are aligned with the cytology results. The correct interpretation of the two findings helps the clinician to reduce the risk of unnecessary invasive procedures in patients with a low probability of presenting thyroid cancer, while facilitating the identification of patients at higher risk of cancer.