Marking axillary nodes with 4% carbon microparticle suspension before neoadjuvant chemotherapy improves sentinel node identification rate and axillary staging

Background and Objectives Marking positive lymph nodes (LNs) before neoadjuvant chemotherapy (NAC) may improve the accuracy of sentinel lymph node biopsy (SLNB). The aim of this study was to determine the feasibility of marking LNs with 4% carbon microparticle suspension (CMS) before NAC and to evaluate if this technique would improve the SLNB identification rate. Methods A prospective study of patients with cT1-T4, cN1-N2 breast cancer who underwent US-guided fine-needle aspiration biopsy (FNAB) of suspected LNs and concomitant marking with 4% CMS was performed. After NAC, LNs marked with 4% CMS and those marked with Patent Blue V dye (PBV) were identified and resected. Results Of the 123 patients included, 74 (60.1%) had positive LNs at FNAB. During axillary surgery, 4% CMS was identified in 121 of 123 patients (98.3%) and blue sentinel LNs in 91% (112 of 123 patients) (P = .0103). Comparing isolated results of PBV and 4%CMS + PBV, the association was better in identifying positive LNs (72.2% vs 97.7%) (P = .02). Conclusion The association of 4% CMS and PBV is feasible and significantly increased the identification rate of positive LNs. 4% CMS may play an important role as a complementary technique in patients submitted to NAC.