The Role of Core-Needle Biopsy as a First-Line Diagnostic Tool for Initially Detected Thyroid Nodules.

Background: The aim of this study was to evaluate the role of core-needle biopsy (CNB) as a first-line diagnostic tool for initially detected thyroid nodules.

Methods: This observational study evaluated 632 initially detected thyroid nodules in 632 consecutive patients who underwent CNB between October 2008 and December 2011. CNB results were categorized into the six categories of the Bethesda System. A final diagnosis of malignancy was based on surgery or CNB, whereas a final diagnosis of benign nodules was based on surgery, two benign biopsy results, or benign cytology of stable size after one year. The rates of Bethesda category 1 and inconclusive results, diagnostic performance, unnecessary surgery, and complications were evaluated. Subgroup analysis based on nodule size was performed. Risk factors for inconclusive results were evaluated by multivariate logistic regression analysis.

Results: The rates of Bethesda category 1 and inconclusive results by CNB were 1.3% and 5.9%, respectively. The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value for the diagnosis of malignancy were 97.6%, 90.0%, 100%, 100%, and 92.3%, respectively. The rate of unnecessary surgery was 0.5%, and the complications rate was 0.2%. Based on subgroup analysis, the diagnostic performance was not significantly associated with nodule size. There were no independent risk factors associated with inconclusive results.

Conclusion: CNB showed low rates of Bethesda category 1 and inconclusive results and a high diagnostic accuracy. CNB also minimized unnecessary surgery. CNB seems to be a promising diagnostic tool for patients with initially detected thyroid nodules.