Hypoechoic nodule structure increases non-diagnostic rate of thyroid fine needle aspiration biopsy

Abstract

Aim: Thyroid fine needle aspiration biopsy (FNAB) performed with ultrasonography is an effective method in diagnosing thyroid cancer. Nevertheless, some of them have non-diagnostic results. The aim is to investigate the factors that affect non- diagnostic result. Material and Method: FNABs of 361 nodules of 361 patients were analyzed retrospectively. The patients were divided into two groups as fine needle aspiration biopsy result with and without non-diagnostic. The groups were compared according to demographic, clinical and sonographic data. Results: Non-diagnostic rate was 14.4% in all biopsies. There was no difference in terms of age, gender, previous thyroid surgery history, smoking history, aspirin use, Hashimoto’s thyroiditis, toxic nodule. Sonographic findings of the thyroid glands and nodules were similar. Only the echogenicity of the nodule was found to affect the non-diagnostic result (p=0.015). In the post hoc analysis, the difference was found to be caused by hypoechoic nodules (32.7% versus 15.5). It was observed that the significant relationship found in univariate logistic regression analysis (p=0.009, OR: 3.227, CI: 1.334-7.803) continued in multivariate analysis (p=0.024, OR: 3.175, CI: 1.163-8.668). Conclusion: Only hypoechoic echogenicity increases the risk of non-diagnostic rate. Other factors do not increase the nondiagnostic rate.