Long-term Tracing of Carbon Nanoparticles for Axillary Lymph Node Dissection in Patients with Fusion Lymph Nodes before Neoadjuvant Chemotherapy

Abstract Background: The regression model of positive nodes in breast cancer after neoadjuvant chemotherapy (NAC) remains controversial. This study aimed to investigate this regression model by injecting and tracing carbon nanoparticles (CNs) into the fusion node prior to NAC in patients with breast cancer. Methods: Guided by ultrasound, 0.3 mL of CNs suspension was injected in a fusion node prior to NAC in 110 patients with local advanced breast cancer. Patients underwent breast surgery and total axillary lymph node dissection following 2-6 cycles of NAC. The distribution by intercostobrachial nerves (ICBN) of positive nodes, black-stained nodes and lymphovascular invasion was investigated by response to NAC. Results: When patients were ranked by response to NAC (from sensitive to resistance), the number of positive nodes increased, as did the proportion of lymphovascular invasion, the number of black-stained nodes decreased. A significantly negative relationship was found between the number of positive nodes and the number of black-stained nodes (p < 0.001). The positive nodes in patients with sensitive consequence followed the rule from under the ICBN to above the ICBN. However, there was counter-example (skip metastasis) in the patients with resistance result. Conclusion: The regression model of positive nodes follows the rule from upper to under, inner to outer in the patients with sensitive consequence to NAC. Long-term staining and tracing by CNs might provide an acceptable and feasible technique to investigate the regression model of positive nodes, and would be a potential method for NAC-treated patients by using of ICBN. Trial registration: NCT 03355261. Retrospectively registered on November 28, 2017.