Validation study on the clinical usefulness of the ICG fluorescence method for detecting sentinel lymph node in early-stage breast cancer in comparison with the dye method.

Abstract

1122 Background: Sentinel lymph node (SLN) biopsy using indocyanine green (ICG) fluorescence method is a technique that utilizes the fluorescing property of ICG reagent that is used in the dye method. Flow of lymph can be confirmed as real time image from outside the body, and this method is the best for intra-operative sentinel lymph node biopsy. To assess the diagnostic performance of SLN biopsy using ICG fluorescence technique, prospective multicenter study was performed compared with blue dye method. Methods: Patients with T1-3 primary breast cancer without lymph node metastasis were assigned in this study. A combination of ICG as a fluorescence emitting source and indigocarmine as a blue dye were injected in the subreolar area and lymphatic flows were traced with PDE camera (a charge coupled device, Hamamatsu Photonics Co, Japan) and a real time image guided surgery enabled to identify the florescence signal of SLN after meticulous dissection. Extracted lymph nodes were examined for the first SLN or the second and further SLNs and classified in terms of ICG fluorescence, blue dye. Primary endpoint in this study is the difference in the number of lymph nodes identified by the fluorescence and the dye method. Secondary endpoints are identification rate, metastatic rate to SLNs and metastatic rate by order of SLNs. Results: Ninety-nine eligible patients were included in this study. The number of lymph nodes identified by fluorescence method was significantly larger than dye method (p<0.001). The SLN identification rate of fluorescence and dye method was 99% and 78%, respectively (p<0.001). Twenty of 99 patients had a positive SLN and ICG fluorescence method identified all these patients. The first SLN identified had both ICG fluorescence and blue dye (77%) or ICG fluorescence alone (23%). Of the 20 patients with lymph node metastasis, 100% was positive in the first SLN. Conclusions: SLN biopsy using ICG fluorescence achieves a high identification rate and is superior to dye method. The first SLN identified by ICG fluorescence method represents the exact axillary status. Direct comparison between ICG fluorescence and radio isotope method is currently on the way.