Introduction: Fine needle aspiration biopsy (FNAB) plays an essential role in the evaluation of thyroid nodular disease (TND). It reduces the rate of unnecessary thyroid surgery for patients with benign nodules, and allows the choice of the appropriate surgery. In our department, 2124 FNAB were performed in 10 years. 60% of them are now ultrasound guided (UGFNAB).
Objective: To access the accuracy of FNAB in our hospital.
Methods: Retrospective study of 204 patients medical files who underwent FNAB and who were submitted to surgery, between 1999 and 2010. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of FNAB (without UG and UG) were examined based on cytohistologic correlation. All statistical evaluation was made using an SPSS software. A P value <5% was considered statically significant. Classification of cytological results were adapted from Bethesda system.
Results: Cytological results were benign in 78% of the cases. From the remaining, 8.6% were malignant and 13.4% were follicular neoplasms. Histological results were benign in 86.7% and malignant in 13.3%, being 9.1% papillary carcinomas. After the evaluation of cytohistologic correlation, there were 79.4% of true-negatives, 15.7% of true-positives, 3.4% of false-negatives and 1.5% of false-positives. All the false-negatives (7) correlates with large nodules (6) or with non dominant nodule in histology (not analized by FNAB). The sensitivity was 95.9%, the specificity was 91.4%, the negative predictive value was 82.1% and the positive predictive value was 98.2%. The comparison of FNAB without UG or UGFNAB demonstrates a false predictive value of 64.7 vs 100% and a positive predictive value of 100 vs 88.9% There were no unsatisfactory samples.
Conclusions: The results show a good accuracy of FNA in our hospital, with a high sensibility and specificity. Our results are similar to the published data.
30 Apr - 04 May 2011
European Society of Endocrinology