Ultrasound features and preoperative accuracy of the fine needle aspiration biopsy in detection of thyroid carcinomas

To analyze the ultrasound (US) characteristics and fine needle biopsy (FNAB) of thyroid carcinomas (TCs) prior to surgery and compare with postoperative histopathology and to determine FNAB sensitivity and specificity.

Retrospective analysis of the US data during 1999-2015 was performed, as well as analysis of FNAB results and using histopathology report as "gold standard" the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of this method was evaluated.

Data revealed that tumors >51 mm were declining by 50% in the period 2011-2015 compared to 2005-2010 or by 18% 2011-2015 compared to 1999-2004 and significant increase was detected in diagnosis of multicentric tumors. The analysis revealed that FNAB has sensitivity = 65.7% CI (0.59% - 0.71%) and specificity = 50% CI (0.43%-0.56%), PPV = 56.9% and NPV = 59.2%.

We found increasing detection of smaller TCs, as well as more frequent detection of multicentricity of the neoplastic foci. FNAB results in our study revealed low sensitivity and specificity. Major limitation of the study was inability to exactly separate US guided from non US guided FNAB in evaluation of the sensitivity and specificity, due to retrospective nature of the analysis. Further studies evaluating only US guided FNAB should be performed.