Cytopathologic criteria and size should be considered in comparison of fine-needle aspiration vs. core-needle biopsy for thyroid nodules: results based on large surgical series.

purposeTo evaluate and compared the diagnostic performances of FNA and CNB using various cytopathologic criteria and size subgroups to see how the comparison results differ accordingly.

methodsFrom May 2012 to May 2019, 8187 thyroid nodules in 8139 patients who had undergone preoperative US-guided FNA or CNB at outside clinics were included in this retrospective study (mean size: 11.9 ± 9.5 mm). Preoperative US-FNA was performed in 7496 (91.6%) nodules and US-CNB was performed in 691 (8.4%) nodules. Propensity score matching was used to compare the sensitivities between FNA and CNB in diagnosis of malignancy and neoplasm according to different cytologic test criteria.

resultsOf the 8187 thyroid nodules, 7833 (95.7%) were malignant and 354 (4.3%) were benign. Mean size of the thyroid nodules in the CNB group was significantly larger than the FNA group, 15.7 ± 12.7 mm vs. 11.6 ± 9.0 mm, respectively (P < 0.001). After matching, sensitivity in the CNB group were significantly higher in the total population, and in subgroups <10 mm for criteria 1 and 2 (all P < 0.05, respectively). No significant differences were seen between the sensitivities of FNA and CNB for nodules ≥10 mm regardless of criteria in diagnosis of malignancy or neoplasm (all P > 0.05, respectively).

conclusionsResults comparing sensitivities between FNA and CNB differ according to the different cytopathologic criteria used for calculation. CNB has significantly higher sensitivity to FNA in subcentimeter nodules when using criteria 1 or 2. Diagnostic sensitivities did not show significant differences for nodules ≥10 mm regardless of the cytopathologic criteria used, that should be considered in selecting biopsy methods.