Methylene blue dye as an alternative to isosulfan blue dye for sentinel lymph node localization

Background: Our study describes the use of methylene blue dye as an alternative to isosulfan blue dye to identify the sentinel lymph node (SLN). Methods: A retrospective analysis was performed of 112 breast cancer patients (113 axillae) who underwent SLN biopsy (SLNB) with methylene blue dye and Tc-99m-labeled sulfur colloid for SLN identification. All SLNs were submitted for intraoperative frozen section analysis, hematoxylin and eosin stain, and immunohistochemical evaluation. Patients with a pathologically negative SLN did not undergo further axillary lymph node dissection. Results: Of 112 patients who underwent SLNB, the SLN was identified in 107 (95.5%); 104 (92.8%) were identified by methylene blue dye. In a subset of 99 patients with recorded isotope status in relation to blue nodes, concordant identification with both dye and isotope was observed in 94 (94.9%). Of patients with identified SLNs, 32 (29.9%) of 107 contained metastatic disease, with 31 (96.9%) of 32 identified by methylene blue dye. The SLN was the only positive node in 18 (60.0%) of 30 patients. Conclusions: SLNB with methylene blue dye is an effective alternative to isosulfan blue dye for accurately identifying SLNs in breast cancer patients.