Extra-axillary sentinel lymph nodes in breast cancer

Abstract

Extra-axillary locations are known sites of lymph node metastases in patients with carcinoma of the breast. A technique utilizing a gamma probe was used to identify hot spots representing sentinel nodes residing in either axillary or extra-axillary locations in 680 patients with operable, clinically node-negative breast cancer. All identified sentinel nodes were excised. Results showed that extra-axillary hot spots were found in 6.5% of patients. This rate increased to 14.8% if patients were injected with 8.0 ml unfiltered Technetium-99m-Sulfur colloid. Extra-axillary metastatic disease was identified in 6.8% of patients with extra-axillary hot spots. In patients with extra-axillary drainage, pathologically-positive nodes were exclusive to extra-axillary sites (ie, no axillary metastases) in 4.5% of cases. Factors found to increase the likelihood of identifying extra-axillary hot spots included; an increased volume of injection, medial or central tumor locations and T3 primary tumors. Gamma probe-guided techniques can identify extra-axillary sentinel nodes, which are at risk for harboring metastatic disease. Removal of these nodes can be done with little morbidity and may improve staging in the individual patient.