P69: Concordance of peritumoral technetium 99m colloid and subareolar blue dye injection in breast cancer sentinel lymph node biopsy

Abstract

Background: Sentinel lymph node (SLN) mapping has emerged as a less invasive method of axillary lymph node staging in patients with breast cancer. Blue dye and radioisotopes are commonly used agents to localize SLNs, but the optimal site for the injection of these agents continues to be debated. In this study we evaluated whether subareolar (SA) injection of blue dye led to the identification of the same SLNs as peritumoral (PT) injection of technetium colloid. Methods: From March 2003 to November 2005, 85 patients with invasive breast cancer, diagnosed by core needle biopsy, were included in this study. Approximately one hour prior to time of surgery, all patients underwent peritumoral injection of 37 Mbq of Tc-99m-sulfur colloid. In the operating room, 3 to 5 mls of 1% lymphazurin was injected into the subareola area and the breast was massaged for 5 minutes. Axillary incisions were made lateral to the pectoralis major muscle and just below the hair bearing area. SLNs were identified with the aid of a hand-held gamma probe or visualization of blue stained lymphatic channels or nodes. SLNs were categorized as radiolabeled-only, blue-only, or radiolabeled-blue. Results: The mean number of SLNs identified was 1.8 (range 1-5). With the combination of these two methods 83 out of 85 patients (97.6%) had successful identification of SLNs. Eighty patients (94.1%) had SLNs that were blue and 82 patients (96.4%) had radiolabeled SLNs. Seventy-nine patients had at least one SLN that was both blue and radiolabeled, yielding a concordance rate of 92.9%. Metastatic disease was identified in SLNs of 19 patients. All lymph nodes with evidence of metastasis were both blue and radiolabeled. Conclusions: Our study showed a high degree of concordance between SA blue dye and PT radiocolloid in identification of SLNs. These results further support that the breast parenchyma and subareolar plexus drain to similar SLNs within the axilla. These two techniques can complement each other in localizing SLNs with a high success rate.