Diagnosing and Managing the Malignant Axilla in Breast Cancer

Abstract

The management of the malignant axilla remains a controversial topic. Although many issues have been resolved with the results of randomised controlled trials, there are still areas where evidence is lacking. This review will focus on the current diagnostic methods used to detect lymph node (LN) metastases as well as the impact of volume of LN disease on the choice of axillary management. The roles of surgical excision, radiotherapy and systemic therapy as treatment modalities for LN metastases will also be explored with particular emphasis on the use of neo-adjuvant chemotherapy (NACT). Lastly, new innovations in contrast-enhanced ultrasound (CEUS) will be discussed as a potential test for precise and personalised axillary staging. The results of the ACOSOG Z011 trial are widely accepted and axillary conservation is now part of mainstream practice in many parts of the World for patients with sentinel lymph node (SLN) metastases and clinical T1/ T2 N0 M0 tumours who had breast-conserving surgery alongside adjuvant whole breast radiotherapy and systemic therapy. Determining the volume of metastatic disease in the axilla is important for treatment decisions and de-escalation of axillary surgery after NACT in patients with biopsy proven pretreatment LN metastases may become part of routine practice for selected patients once long-term outcomes are known. Novel methods to identify LN metastases have been developed over the last 10 years including the use of injected microbubbles and CEUS to locate and biopsy sentinel lymph nodes (SLN). Technological advances including ultrafast and super-resolution ultrasound have the potential to increase the diagnostic accuracy of axillary CEUS. The main drawback to current axillary management is the lack of a reliable objective test to quantify LN metastases. The de-escalation of axillary surgery is timely but without an objective non-invasive imaging test to replace the axillary lymph node dissection (ALND), clinicians are reliant on predictive medicine rather than precision diagnostics to plan individual treatment. New innovations in CEUS have the potential to provide a reproducible non-invasive test, which can be used in the future to investigate LN metastases in patients with breast cancer.