An Updated Review on the Emerging Role of Indocyanine Green (ICG) as a Sentinel Lymph Node Tracer in Breast Cancer

Simple Summary Dual lymphatic mapping using radioisotope and blue dye is the gold standard technique for performing sentinel lymph node biopsy (SLNB) in breast cancer. However, it is associated with significant risk for anaphylactic reactions to blue dye, and with difficulties related to the supply and usage of radioactive agents. Therefore, there is an imperative need for the development of novel sentinel lymph node tracers that are safe, cheap and easily available. Indocyanine green (ICG) fluorescence is the most promising among the innovative techniques for lymphatic mapping in breast cancer and it has been introduced in everyday clinical practice in several countries. The literature on the use of ICG for SLNB in breast cancer is constantly growing. This is an updated review of some recent studies that show how ICG could complement or even replace the conventional sentinel lymphatic mapping tracers.Abstract Sentinel lymph node biopsy (SLNB) has become the standard of care for clinically node-negative breast cancer and has recently been shown by clinical trials to be also feasible for clinically node-positive patients treated with primary systemic therapy. The dual technique using both radioisotope (RI) and blue dye (BD) as tracers for the identification of sentinel lymph nodes is considered the gold standard. However, allergic reactions to blue dye as well as logistics issues related to the use of radioactive agents, have led to research on new sentinel lymph node (SLN) tracers and to the development and introduction of novel techniques in the clinical practice. Indocyanine green (ICG) is a water-soluble dye with fluorescent properties in the near-infrared (NIR) spectrum. ICG has been shown to be safe and effective as a tracer during SLNB for breast cancer and accumulating evidence suggests that ICG is superior to BD and at least comparable to RI alone and to RI combined with BD. Thus, ICG was recently proposed as a reliable SLN tracer in some breast cancer clinical practice guidelines. Nevertheless, there is lack of consensus regarding the optimal role of ICG for SLN mapping. Specifically, it is yet to be determined whether ICG should be used in addition to BD and/or RI, or if ICG could potentially replace these long-established traditional SLN tracers. This article is an updated overview of somerecent studies that compared ICG with BD and/or RI regarding their accuracy and effectiveness during SLNB for breast cancer.