Comparison of blue dye and isotope with blue dye alone in breast sentinel node biopsy

Background: Sentinel lymph node biopsy (SNB) is rapidly gaining acceptance as an alternative to axillary dissection (AD) in patients with early breast cancer. Debate continues regarding the optimum technique for sentinel node (SN) mapping. We have used our series of 364 SNBs to compare two different techniques. Methods: A retrospective review of patients undergoing SNB by surgeons in our breast service. Overall results were analysed, with particular attention to those having blue dye alone and those having blue dye in combination with radio-labelled colloid. SNs were analysed using haematoxylin-eosin and immunohistochemical staining. Results: SN identification rates were similar: 96% for dye alone and 89% for dye and colloid in combination. Twenty-one per cent of SN mapped with dye alone contained metastases, compared to 30% with dye and colloid in combination. The false-negative rate was correspondingly higher in the dye alone group (21 vs 2.8%). Conclusion: SNB using dye and colloid in combination was significantly superior to dye alone in this series. We advocate using both dye and colloid for intraoperative SN mapping.