Abstract: Background and purpose: Indocyanine green (ICG) combined with rituximab (Rit) produces a new receptor-targeted tracer (ICG-Rit). This study aimed to investigate the feasibility of ICG-Rit as a fluorescent tracer for sentinel lymph node biopsy (SLNB) of breast cancer. Methods: A total of 96 patients with primary breast cancer were included in the Breast Cancer Center, Shandong Cancer Hospital and Institute. The mass ratio of the preparation reagent was 93.75 μg of ICG∶375.00 μg of Rit. ICG-Rit and combined tracer (methylene blue and isotope) were injected into the breast before operation. SLNB was performed by the combined method, lymph nodes were detected by fluorescence imaging, and gray-scale values were recorded. We analyzed the lymph node imaging of ICG-Rit and evaluated the consistency of the combined ICG-Rit method. We observed patient’s allergic reaction and detected postoperative eosinophil count. Results: The imaging rate of ICG-Rit was 97.0% (97/100). The mean and median of sentinel lymph node (SLN) in ICG-Rit imaging were 2.44 and 2, which were lower than those detected by isotope (2.80 and 3), respectively. Compared with the combined method, the accuracy of ICG-Rit SLNB was 97.0% (97/100), the sensitivity was 96.2% (25/26), the false negative rate was 3.8% (1/26), and the kappa value was 0.973 (P<0.001). The highest gray value of lymph nodes was 254, which was concentrated in 220-254. It was difficult to detect fluorescence in patients with gray value ＜220 and lacked continuity. The patients who were enrolled did not have an allergic reaction before operation, and the postoperative eosinophil count did not increase. Conclusion: ICG-Rit, as a fluorescent tracer, can reduce the imaging of non-SLN (n-SLN). Compared with the combined method, the accuracy and coincidence rate are high, and the safety is good.

Key words: Breast cancer, Sentinel lymph node biopsy, Indocyanine green-rituximab