Objective: Ultrasound-guided core needle biopsy (UG-CNB) is a procedure that is often performed either after repeated inadequate or nondiagnostic ultrasound-guided fine-needle aspiration (UG-FNA) or in combination with UG-FNA in the evaluation of thyroid nodules. The purpose of this study was to compare the efficacy and safety of UG-CNB and UG-FNA for evaluating thyroid nodules.
Methods: This was a retrospective study of 350 consecutive patients who had thyroid nodules biopsied by UG-CNB or UG-FNA from January 2007 until November 2011 at our institution. Biopsy results were compared to the surgical specimen pathology reports for the 105 patients who subsequently underwent hemi- or total thyroidectomy in order to determine whether UG-CNB has advantages over UG-FNA for diagnosing thyroid malignancy and neoplasia.
Results: Out of 461 thyroid nodules biopsied from 350 patients, 365 (79%) involved UG-CNB and 96 (21%) involved UG-FNA. The UG-FNA biopsy group had a significantly higher rate of inadequate sampling than the UG-CNB group (P<.0001; Fisher's exact test). Out of 365 UG-CNB samples, 6 (2%) were deemed inadequate for histologic diagnosis, whereas 26 (27%) of the 96 UG-FNA samples were considered inadequate for cellularity. Comparison of biopsy results with the surgical specimen pathology reports revealed that the diagnostic accuracy of UG-CNB and UG-FNA for detecting malignancy was similar, at 89 and 94%, respectively (not significant by Fisher's exact test). However, the UG-CNB group had a higher detection rate for benign follicular lesions compared to the UG-FNA group (65% versus 48% for UG-FNA; P = .002). Although UG-FNA detected neoplasia with high sensitivity (100%), the specificity was poor (30%). Neither biopsy group had any significant immediate or delayed procedure-related complications.
Conclusion: Our study demonstrated that UG-CNB is safe and is less likely to result in a nondiagnostic biopsy. The accuracy of the UG-CNB technique is similar to that of UG-FNA for detecting thyroid malignancy.