Background: Lymphatic mapping in breast cancer performed solely by intraparenchymal injections of blue dye remains an accepted method of identifying sentinel nodes, largely because of its simplicity. As currently practiced, the technique is associated with a marked learning curve, variable identification rates of sentinel nodes, and high false-negative rates. The purpose of this study is to improve dye-only lymphatic mapping of the breast by using an alternative site for injection of blue dye: the subareolar lymphatic plexus.
Study design: In the 10 months between August 1998 and May 1999, 40 women with operable breast cancer in stages I and II underwent lymphatic mapping and sentinel node biopsy performed solely by subareolar injections of blue dye, followed by complete axillary node dissection. The technique involved the injection of 5 mL of 1% isosulfan blue into the subareolar plexus, which consists of breast tissue located immediately beneath the areola. No peritumoral injections of blue dye were performed. The ability of subareolar dye injections to identify sentinel nodes and accurately predict the pathologic status of the axilla was determined and compared with published results for dye-only lymphatic mapping using intraparenchymal injections.
Results: The identification rate of sentinel nodes was 98% (in 39 of 40 patients). Axillary basins harboring positive lymph nodes were found in 15 of these 39 patients (38.5%). Sentinel nodes correctly predicted the status of these 15 positive axillary basins in 100% of the patients. There were no false-negative sentinel node biopsies, indicating a false-negative rate of 0 (in 0 of 15). The overall accuracy, sensitivity, and specificity were 100%.
Conclusions: Compared with other series of dye-directed lymphatic mapping, the present study of dye-only injections into the subareolar plexus demonstrates a high sentinel node identification rate, absent false-negative rate, and rapid learning curve. On the basis of these findings, we propose that injections into the subareolar lymphatic plexus are the optimal way to perform dye-only lymphatic mapping of the breast.