Is the use of blue dye really necessary in axillary sentinel lymph node biopsy in staging of breast cancer?

Sentinel lymph node biopsy (SLNB) is the standard of care for staging the clinically node-negative axilla in early breast cancer. Evidence guiding current practice describes dual localization technique using Patent blue dye and radioisotope (99mTc). Adverse effects of blue dye include 1:1000 risk of anaphylaxis, skin staining and loss of plane visibility, which may increase operative time and reduce resectional accuracy. The risk to a patient posed by anaphylaxis may be greater when operating in a unit without on-site ITU support - a situation more common with recent restructuring during the COVID-19 pandemic. Aim is to quantify the benefit of blue dye above radioisotope alone in identifying nodal disease. This is a retrospective analysis of prospectively collected sentinel node data including all consecutive sentinel node biopsies in a single center during the period 2016-2019.In terms of results, 760 sentinel nodes were taken in 435 patients. 59 nodes (7.8%) were detected by blue dye alone; 120 (15.8%) 'hot' only, 581 (76.5%) hot and blue. 4 of the blue only nodes contained macrometastases but 3 of these patients had further hot nodes excised that also contained macrometastases. 1 out of 435 patients (0.2%) had macro metastatic disease identified as a result of blue dye alone which would have been missed had it not been used. In conclusion, the use of blue dye carries risk and offers little benefit in terms of staging in SLNB and its use may be unnecessary in the hands of the skilled surgeon. This study supports the omission of blue dye, which may be advisable if operating in units without ITU support. If larger studies support these figures, it may become as outdated.