Performance characteristics of ultrasound-guided fine-needle aspiration of axillary lymph nodes for metastatic breast cancer employing rapid on-site evaluation of adequacy: analysis of 136 cases and review of the literature.

Background: It has been demonstrated that axillary ultrasound-guided fine-needle aspiration (US-FNA) has excellent positive predictive value for the axillary lymph node status of patients with breast cancer before surgery or neoadjuvant therapy and, thus, can obviate the need for sentinel lymph node biopsy in FNA-positive patients. However, US-FNA has only moderate sensitivity, in part because of the collection of nondiagnostic or equivocal specimens. Rapid on-site evaluation for adequacy (ROSE) can improve definitive diagnosis rates but has not been well characterized in this setting.

Methods: One hundred thirty-three patients with breast carcinoma were identified who underwent 136 US-FNAs of axillary lymph nodes, all with ROSE, and the results were correlated with the diagnosis on a subsequent surgical procedure.

Results: The adequacy rate was 95.6% (130 of 136 FNAs), and a definitive diagnosis was made in 91.2% (124 of 136 FNAs). Among definite diagnoses, sensitivity was 75%, specificity was 100%, the positive predictive value was 100%, and the negative predictive value was 79%. Sources of false-negative and potential false-positive diagnoses were evaluated among these cases and in the literature.

Conclusions: Small metastasis size is the most common cause of false-negative results, whereas interpretation errors by pathologists are quite rare. ROSE appears to improve adequacy and definitive diagnosis rates and, thus, can more accurately triage patients to appropriate care.