Evaluation of breast lymphatic pathways with indocyanine green fluorescence imaging in patients with breast cancer

Background: In patients with early breast cancer, sentinel lymph node biopsy (SLNB) has been emerging as a new standard of care. The use of SLNB with a blue dye is convenient and safe, but it requires a high level of technical skill. Recently, an instrument that can provide fluorescence imaging of lymphatic flow has been introduced. In the present study, we analyzed breast lymphatic pathways and discussed its potential as a modality to complement the use of SLNB with a blue dye. Methods: Thirty-seven consecutive patients with breast cancer were examined. To obtain fluorescence imaging, an invisible near-infrared fluorescence imaging system was used. After indocyanine green was subdermally injected in the subareolar site and at two sites around the tumor, the subcutaneous lymphatic drainage pathway (LDP) was observed. Results: In 27 (72.9%) of the patients, the number of LDP from the periareolar area was one or two. In 21(63.6%) of 33 patients with subdermal injection around the tumor, no LDP was observed from the peritumoral area. Lymphatic connection between the peritumoral area and the periareolar area was observed very frequently (91.7%). In 26 (70.3%) of the patients, multiple routes joined together and only one route was ultimately directed to the axilla. Significant correlation was seen between body mass index (BMI) and the transit time to the axilla after injection (p = 0.0038). Additionally, a significant correlation was seen between the number of LPD from the periareolar area and the distance between detected SLNs and the fluorescence line-disappearing point (p = 0.034). Conclusions: This instrument can provide some important information, and can be an available and reliable navigator for SLNB with a blue dye.