Clinical significance of discordances in sentinel lymph node reactivity between radioisotope and indocyanine green fluorescence in patients with cN0 breast cancer

Abstract

Background/Objective: To evaluate the usefulness of combining radioisotopes (RI) and indocyanine green (ICG) and investigate discordances in sentinel lymph node (SN) reactivity using each tracer in cN0 breast cancer patients. MethodsIn total, 338 cN0 primary breast cancer patients who underwent SN biopsy with RI and ICG and axillary lymph node (ALN) dissection were included. SN positivity with RI, ICG, and a combination of RI and ICG was denoted as SN(RI), SN(ICG), and SN(RI+ICG), respectively. We retrospectively estimated metastatic SN detection rates, each method's discordance rate, and the correlation of discordances in SN reactivity with postoperative N staging. ResultsThe combination of RI and ICG had higher metastatic SN detection rates (99.7%) than RI or ICG alone (91.7% and 96.4%, respectively; p < 0.01). The discordance rate between SN(RI) and SN(ICG) in detecting metastatic SNs was 11.3% (38/337 cases). The absence of SN(RI), cT stage (cT2-3), higher histological grade (G3), and histological type (special type) were identified as risk factors of pN2-3 disease (odds ratios: 8.64, 2.56, 1.92, and 3.28, respectively; p < 0.01). ConclusionDiscordances in SN reactivity between RI and ICG helps in identifying SN metastasis. Although the absence of SN(RI) is rare, it is a significant sign of advanced ALN metastases. The findings of our study indicate that ALN dissection should be considered for accurate nodal staging in such cases.