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Background: For post-neoadjuvant chemotherapy patients with breast cancer, sentinel lymph node biopsy (SLNB) was recommended using the dual-tracer mapping technique (radioisotope plus blue dye) or placing a biopsy clip into the positive node at diagnosis and identifying it at the time of surgery due to SLN identification rates were lower and false negative rates were greater for patients with local advanced BC than those of patients with early-stage BC in the absence of NAC. Our previous clinical trial has indicated that the real-time ICG fluorescence (RT-ICG) imaging technique could improve the diagnostic sensitivity and detection accuracy for SLNB.

Methods: The SLNs was detected by conventional procedures of blue-dye (Indigo carmine) plus 99mTc radioisotope (dual-tracer) and combined with concurrent RT-ICG technique. The positivity of each single SN by each single tracer (blue dye, ICG, or radioisotope alone) was counted and identified, respectively. 51 enrolled cN1patients after NAC are required to undergo SNB followed by completion axillary lymph node dissection (CND). The identification rate and false negative rate of each single tracer and their summation (triple tracer) were calculated by comparing the results of the SLNB and the histopathology of the resection specimens of CND. 

Results: post-neoadjuvant patients, the identification rate and false negative rate of each single procedure for SLNB was 84.3% and 5.9% when used Indigo Carmine blue, 94.1% and 0 when used ICG fluorescence, 92.2% and 3.9% when used RI, respectively. In contrast, the total calculation of triple tracer showed that identification rate reached to 96.1% and false negative rate was 0, respectively. 

Conclusions: Our results suggested that the multitracer technique combining blue dye, ICG, and radioisotope is effective method for detection of SLNs in post-neoadjuvant cN+ BC pts. The identification rate and false negative rate of SLNB might be improved by this multiple tracer mapping technique, particularly for patients with ypN(+) after NAC. It is considered that the multi-tracer can complement each other for what was not able to be traced and detected by the single tracer with one mapping material, and that result in totally the improvement of identification rate of SLNB.