Background: We aimed to evaluate the effectiveness of preoperative fine-needle aspiration biopsies (FNAB) by the postthyroidectomy pathology results.
Method: Seven hundred and ninety-five patients with FNAB and following thyroid operations which have been performed between April 2008 and December 2019 were included in this study. By comparing the results of the FNAB and final pathologies, the specificity, sensitivity, FNR, false positivity ratio (FPR), accuracy and also the effect of nodule diameter on these have been evaluated. In Bethesda III subgroup according to FNAB, we investigated the malignancy rates and in whom this risk has been increased more.
Results: In our study, the sensitivity of FNAB is 73.40%, the specificity is 95.33%, the accuracy is 91.81%, FNR is 26.60% and FPR is 4.67%. In the patients with nodules ≥4 cm and < 4 cm respectively, we calculated the sensitivity 20.0% vs 79.76%, specificity 95.73% vs 95.19%, accuracy 89.82% vs 92.78%, FNR 80.0% vs 20.24%, FPR 4.27% vs 4.8%.
Conclusion: Thyroid FNAB is an easy procedure with a high specificity and sensitivity. Nevertheless, when the nodule diameter was ≥4 cm, increased FNR and decreased sensitivity should be kept in mind while evaluating the patients.
Keywords: Bethesda classification; FNAB; atypia of undetermined significance; nodule diameter; thyroid.
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