Sentinel lymph node biopsy surgery was first used to detect sentinel lymph nodes in penile cancer, which in turn eliminated inguinal lymph node dissection. It was not until 1994 that the technique of sentinel lymph node biopsy was first used in the management of patients with breast cancer. The purpose of the procedure is to remove a representative portion of the lymph nodes for pathologic biopsy, which in turn represents the status of the lymph nodes in the region as a whole. Therefore, sentinel lymph node biopsy is not a radical procedure, but rather a testing technique.
Tracers are a key component of the entire technical process of sentinel lymph node biopsy, much in the same way that missile guidance on the battlefield allows for precise strikes. There are many different types of tracers: nucleotide-labeled compounds, blue dyes, indocyanine green, nanocarbon, superparamagnetic iron oxide particles, and so on. Each type of tracer has its own characteristics. Many breast cancer surgeries in China are used to choose blue dye as a tracer. Blue dye is used to visualize the sentinel lymph nodes by entering the lymphatic reflux into the lymph nodes. When blue dye is used as a tracer for sentinel lymph node biopsy, the operator has to search for the sentinel lymph node along the blue-stained lymphatic vessels. It is worth noting that in current studies on the accuracy of different tracers of the sentinel lymph nodes, false-negative rates, and the safety of negative sentinel lymph node free axillary lymph node dissection, nuclear combined with blue dye or the nuclear method alone has been shown to be safe and reliable.