The Roles of Ultrasonography in the Management of Axillary Node Metastases in Breast Cancer

In patients with early stage breast cancer, surgical management of the axilla has become less invasive. Multiple randomized control trials have demonstrated that in patients with minimal axillary nodal disease, complete axillary lymph node dissection does not offer a survival benefit when compared to sentinel lymph node biopsy alone. Ultrasonography of the axilla and ultrasound guided biopsy of suspicious lymph nodes has become a highly specific test to identify locoregional disease. Nodal metastasis detected by ultrasound guided lymph node biopsy has allowed patients to be treated as “lymph node positive” or N1, receive neoadjuvant chemotherapy and undergo a subsequent definitive axillary operation. In those patients who achieve a pathologic complete response after neoadjuvant chemotherapy, however, removal of axillary nodes that are free of residual cancer may be of no benefit. Targeted axillary dissection is a novel technique that allows limited, image guided removal of the previously biopsied axillary nodes and the sentinel lymph node during definitive axillary dissection following neoadjuvant chemotherapy. This practice relies on the specificity of ultrasound guided axillary lymph node biopsy to detect disease as well as the placement of markers that label the biopsied node. Contemporary research that utilizes ultrasound to differentiate between patients with minimal axillary nodal metastasis from those with extensive axillary nodal disease will contribute substantially to the less invasive surgical management of the axilla.