Abstract: Sentinel lymph node biopsy has been proved to be the standard treatment for early breast cancer patients with negative axillary lymph node. The study related to the tracer has become one of the hottest topics in breast cancer research. At present, the biopsy is often performed using the tracer of isotope, blue dye or both of them. However, some deficiencies of the 2 tracers restrained their applications, which resulted that the rate of the procedure is limited to only about 60% of patients in developed countries and less than 5% of patients in China and other developing countries. In recent years, a variety of new tracers have emerged, such as indocyanine green, contrast-enhanced ultrasound using microbubbles, superparamagnetic iron oxide nanoparticles. In this article, we introduced the characteristics of these 3 substances and reviewed the related research on the new tracers. In conclusion, the new tracers are still in the preliminary stage of research, and further research is needed for clinical application.

Key words: Breast cancer, Sentinel lymph node biopsy, Tracer