Clinical significance and management of extra-axillary sentinel lymph nodes: worthwhile or irrelevant?

Nonaxillary drainage is demonstrable by lymphoscintigraphy in up to one-third of breast cancer patients, and nonaxillary sentinel lymph node (SLN) biopsy (most frequently of the internal mammary nodes) is the subject of a growing body of literature. It is not yet clear that the identification of nonaxillary SLN significantly affects treatment or outcome in patients with primary operable disease. The greatest future potential for nonaxillary SLNs biopsy is in the management of patients with ipsilateral breast tumor recurrence, where prior axillary surgery may have unpredictably altered the lymphatic drainage of the breast.