Comparison of palpation-versus ultrasound-guided fine-needle aspiration biopsies in the evaluation of thyroid nodules

BACKGROUND: The aim of this study was to compare the results of palpation-versus ultrasound-guided thyroid fine-needle aspiration (FNA) biopsies. FINDINGS: Clinical data, cytology and histopathology results were retrospectively analyzed on all patients who underwent thyroid FNA biopsy in our outpatient endocrinology clinic between January 1998 and April 2003. The same investigators performed all thyroid FNAs (ASC) and cytological evaluations (KP). Subjects in the ultrasound-guided group were older, otherwise there were no differences in baseline characteristics (gender, thyroid function, the frequency of multinodular goiter, nodule diameter and nodule location) between groups. Cytology results in nodules aspirated by palpation (n = 202) versus ultrasound guidance (n = 184) were as follows: malignant 2.0% versus 2.7% (p = 0.74), benign 69.8% versus 79.9% (p = 0.02), indeterminate 1.0% versus 4.9% (p = 0.02), inadequate 27.2% versus 12.5% (p < 0.01). Malignant results were compared with Fisher's exact test. Other cytology categories were compared with chi-square test. Eighteen patients from the palpation- and 23 from ultrasound-guided group underwent surgery. In the palpation-guided group, the sensitivity of FNA was 100%, specificity 94%, positive predictive value 67% and negative predictive value 100%. In the ultrasound-guided group, the sensitivity of FNA was 100%, specificity 80%, positive predictive value 73% and negative predictive value 100%. CONCLUSION: We demonstrate that ultrasound guidance for thyroid FNA significantly decreases inadequate for evaluation category. We also confirm the high sensitivity and specificity of thyroid FNA biopsy in the diagnosis of thyroid cancer. Where available, we recommend universal application of ultrasound guidance for thyroid FNA biopsy as a standard component of this diagnostic technique.