Axillary Lymph Node Biopsy in Newly Diagnosed Invasive Breast Cancer: Comparative Accuracy of Fine-Needle Aspiration Biopsy versus Core-Needle Biopsy

Purpose To compare the diagnostic accuracy of ultrasonographically (US)-guided fine-needle aspiration biopsy (FNAB) and core-needle biopsy (CNB) of the axillary lymph nodes (LNs) of patients with newly diagnosed invasive breast cancer. Materials and Methods This prospective single-center study had institutional review board approval, and written informed consent was obtained. Between April 2011 and March 2012, 178 consecutive patients (182 axillae) were evaluated by using axillary US. Sixty-six axillae fulfilled the inclusion criteria (cortical thickness greater than 2 mm or abnormal morphologic characteristics), and patients with these axillae underwent US-guided axillary LN biopsy. Both FNAB and CNB were obtained from the same suspicious LN. Patients with biopsy-proved metastasis underwent axillary clearance, and those with a negative biopsy underwent sentinel LN biopsy with completion axillary clearance if needed. Diagnostic performance was calculated separately for US, FNAB, and CNB. Statistical differences in sensitivities were evaluated by using the McNemar test. Results From the total study population, 45.6% (83 of 182 axillae) had metastases. A total of 66 axillae underwent both FNAB and CNB. The sensitivity for US was 61.4% (51 of 83 axillae), and specificity was 84.8% (84 of 88 axillae). The sensitivities for FNAB and CNB were 72.5% (37 of 51 axillae) and 88.2% (45 of 51 axillae), respectively (P = .008). Specificity for both was 100% (15 of 15 axillae). The negative predictive value for FNAB was 81.7%, and that for CNB was 91.2%. The positive predictive value was 100% for both methods. Conclusion When accurate preoperative staging of the axilla is needed in patients with newly diagnosed invasive breast cancer, CNB is more sensitive than FNAB. © RSNA, 2013