Axillary Ultrasound for Breast Cancer Staging: an Attempt to Identify Clinical/Histopathological Factors Impacting Diagnostic Performance

Aim: To assess the diagnostic value of pre-surgery axillary ultrasound for nodal staging in patients with primary breast cancer and to identify clinical/histopathological factors impacting diagnostic performance. Study design: Single-center, retrospective chart analysis. We assessed sensitivity, specificity, and positive and negative predictive value of clinical examination as well as axillary ultrasound vs. clinical examination alone. The histopathological results were the standard of truth. In addition, we analyzed clinical and histopathological factors regarding their potential to impact sensitivity and specificity. Results: We enrolled a total of 172 women in the study. Sensitivity of clinical examination plus ultrasound was significantly higher than for clinical examination alone (58% vs. 31.6%). Specificity and positive predictive value were similar while the negative predictive value increased from 63.4% to 73% when additionally applying ultrasound. Sensitivity and specificity of axillary ultrasound were impacted by tumor size (P = 0.2/0.04), suspicious axillary palpation (P < 0.01/<0.01), number of affected lymph nodes (P < 0.01/-) and distant metastases (P = 0.04/<0.01). All other factors had no impact. Conclusion: Since pre-surgery axillary nodal staging is currently used to determine disease management, axillary ultrasound is a useful add-on tool in the diagnostic armamentarium for breast cancer patients. Tumor size, suspicious axillary palpation, number of affected lymph nodes and distant metastases increase diagnostic performance of this diagnostic modality.