Value of repeated fine needle aspiration biopsy (FNAB) in the management of benign solitary thyroid nodules

BACKGROUND: Fine-needle aspiration (FNA) is an invaluable technique used in the evaluation of thyroid nodules. OBJECTIVES: Evaluate the concordance of results for consecutive FNA readings. DESIGN: Retrospective, descriptive. SETTINGS: Two tertiary care centers. METHODS: Demographics were collected along with every FNA result and final pathology results for all patients (aged 9-90 years old) who underwent thyroid surgery from 2010 to 2017. The Bethesda system was used for cytology. Agreement levels were calculated and compared with final pathology. SAMPLE SIZE: Of 1237 initially included, 1134 had at least one FNA performed with results available for review. RESULTS: For the 1134 patients, demographic and clinical data were collection and a comparison was made between the three FNA results; the highest agreement was between FNA 2 and 3 (53.6%); however, the kappa value was consistently low for all comparisons, indicating a poor level of agreement overall. Also, the risk of malignancy was higher in this study than in the 2017 Bethesda system for reporting thyroid cytopathology in FNA cytology categories I and II. CONCLUSION: Repeating FNA biopsies yield different results every time; hence, there is a low level of agreement. The clinical decision should therefore include other important risk factors. Prospective studies could help shed more light on this topic. LIMITATIONS: Retrospective design