Axillary nodal evaluation in patients with breast cancer – When, why and how?

Evaluation of axillary nodes is an integral part of staging breast cancer in the tumor, nodes and metastases (TNM) system. Nodal stage helps guide management decisions and is an important predictor of prognosis. Imaging plays an essential role in axillary nodal evaluation. Over the past decade there has been a trend towards de-escalation of axillary surgery. Certain patients may now forego axillary lymph node dissection even in the setting of a positive sentinel node biopsy (SNB), and some patients may not even undergo an SNB. This has resulted in a need to change the imaging approach to assessing axillary nodes in patients with breast cancer. This article provides an overview of the various imaging techniques used for axillary nodal evaluation. The clinical impact and rationale for appropriate axillary nodal imaging are discussed and an imaging algorithm is proposed.