Introduction

Axillary lymph node status is the most important prognostic factor in breast cancer patients. This chapter details why preoperative staging of the axilla is so important, the different imaging modalities we can employ, the role of preoperative ultrasound-guided biopsy, and highlights possible future developments.

The importance of axillary staging

Staging the axilla for nodal metastases is a crucial step in the management of breast cancer, providing diagnostic information and guiding subsequent management. Traditionally, axillary lymph node dissection has been performed at the time of breast cancer surgery and provides the most accurate information. Clearing the axilla of lymph nodes can be associated with significant morbidity with the development of lymphedema. Patients who have axillary lymph node metastases at the time of diagnosis derive benefit from having the axilla cleared, reducing the risk of local and regional recurrence. In addition, most surgeons feel that providing good local control translates into improved survival, although the evidence for a survival benefit is less clear cut.

More recently less invasive surgical methods have been introduced such as lymph node sampling and sentinel lymph node biopsy (SNB). These procedures aim to provide staging information without the risks associated with complete axillary dissection, and are ideal for patients who are ultimately found to be node negative. The disadvantage is that when a patient is found to have lymph node involvement, a second procedure such as an axillary clearance or radiotherapy is required to adequately treat the axilla.