Influence of the injection technique on the false negative rate of SLNE in multifocal breast cancer

Abstract

We investigated the influence of the injection technique on the false negative rate in identifying the sentinel lymph node in multifocal breast cancer. 958 consecutive patients were divided into unifocal and multifocal breast cancer patients. The scintigrafic and intraoperative detection rate as well as the false negatives were calculated in relation to peritumoral or subareolar injection. In all patients the scintigrafic and intraoperative detection rate exceeded 99%, except in patients with multifocal cancer, who were injected peritumorally. In this group the intraoperative detection rate declined to 96%. In patients with unifocal breast cancer the false negative rate was below 5%, independent of the injection technique. Multifocal breast cancer patients showed a significant dependence on the injection technique. The false negative rate was 26.3% in patients with peritumoral injection and 5.6% in those with subareolar injection. The results clearly demonstrate that in multifocal breast cancer a reliable detection of a SLN is impossible with the peritumoral injection technique. Subareolar injection seems to be a way to operate on multifocal breast cancer with SLNE, but the number of investigated patients is too low for statistic approval. So, prospective studies should be performed to validate these preliminary results before SLNE becomes routine in multifocal breast cancer.