Evaluation of the efficacy and safety of ultrasound guided injection of carbon nanoparticles as a preoperative localizing tool of non-palpable breast cancer and sentinel lymph nodes detection

Objective
This study aimed to measure the efficacy of using carbon nanoparticles in the preoperative localization of early breast cancer (BC) cases as well as in the detection of sentinel lymph nodes in Egypt. In addition, the purpose of the study was to determine whether the efficacy of carbon nanoparticles outweighs their high price and additional shipping fees.
Material and methods
The current pilot study enrolled 16 early BC patients, particularly those eligible for breast-conserving surgery. All patients underwent standardized injection techniques. The operating surgeons provided comprehensive intraoperative findings and postoperative histopathological reports of the excised tissues.
Results
After neoadjuvant chemotherapy (NAC), downstaging of the study subjects was achieved until reaching the TNM stage of T1N1M0 and T1N0M0 in 2 cases (12.5%) and 14 cases (87.5%), respectively. Ultrasound-guided injection of carbon nanoparticles was done, followed by surgical excision on the same day or the day after injection. Eleven patients had positive mass lesions preoperatively, with a mean tumoral size of less than 1 cm in maximum dimension. Moreover, 6 out of the 11 patients showed positive black staining intraoperatively with an accuracy of 68.75%. Postoperative histopathological examination (the gold standard) of axillary specimens revealed that 3 out of 16 of the study population have positive tumor-infiltrated lymph nodes. However, only 2 of these cases demonstrated intra-operative black staining, with the black dye's positive and negative predictive values of staining being 100% and 92.2%, respectively.
Conclusions
Preoperative carbon nanoparticle suspension injection is a safe and effective method for adequate tumoral localization in BC patients. Nevertheless, this pilot study did not provide strong evidence for the adequacy of sentinel lymph node detection due to the small sample size, high cost, and extra shipping fees of the carbon nanoparticles.