A concordance study of subareolar and subdermal injections for breast cancer sentinel lymph node mapping

There is disagreement regarding the preferred injection site for breast sentinel lymph node mapping. The concordance of blue staining and radioactivity in the sentinel nodes of 730 consecutive patients was analyzed based on injection of mapping agents into the same or separate intradermal and subareolar sites. There were no significant differences in identification rates or the mean number of sentinel nodes whether agents were injected into the same or separate sites. In each group, a concordant sentinel node (both blue and "hot") was identified in >90% of patients (P = not significant). There were no significant differences in the percentage of sentinel nodes identified as both blue and hot. Separate subdermal and subareolar injections of mapping agents drain to the same sentinel node as often as injections into the same location. These two injection techniques appear to result in the identification of the same sentinel nodes.