The Comparative Analysis of Multimodal Markers to Identify Sentinel Lymph Node in Breast Cancer

Various markers has been used for SLN biopsy including isosulfan blue (patent blue), indocyanine green (ICG), radioisotope colloid (RAIC) and ultrasound (US) with several advantages and disadvantages. In this study investigators designed an algorithm using the combination of mapping with patent blue, ICG, RAIC and US to compare the accurate identification of SLN in breast cancer patients. The protocol is based on the hypothesis that identification rate of SLN is increased with multiple agents. Patent blue and ICG provides visual guidance. The combination of dyes with sonographic and RAIC method have the potential to prevent obstacles and ensure better outcomes as an identification strategy.

Patent blue provides visual identification of the SLN. ICG fluorescence can be detected percutaneously and by means of fluorescence imaging system in real time. RAI has several advantages, but disadvantages as well, like cost and invisibility. RAI can only be detected and confirmed by means of sound and numerical value through gamma probe. All breast cancer patients underwent axillary ultrasound before SLNB with different mapping combinations. The determination of abnormal axillary lymph node was followed by ultrasound-guided FNA cytology of these nodes. The sonographic abnormality criteria of the nodes were defined as; completely hypoechoic node, asymmetric focal hypoechoic node, cortical lobulation more than 3, cortical thickness >2mm, totally spheric appearance, absence of fatty hilum and compromise of normal vascularity (hypervascularization from various poles). Patients with negative results of FNA would undergo SLNB. Lymphatic mapping was performed with abovementioned dyes and radioactive colloid. Before the incising for SLNB real time intraoperative US was performed and suspicious axillary lymph nodes were seen by ultrasound guidance. In the SLNB operation, radioactive or dyed nodes and sonographically suspicious nodes were removed and labeled separately for pathological examination.