Sentinel Lymph Node Mapping in Breast Cancer Patients Through Fluorescent Imaging Using Indocyanine Green: The INFLUENCE Trial.

Objective: The aim was to compare the (sentinel) lymph node detection rate of indocyanine green (ICG)-fluorescent imaging versus standard-of-care 99m Tc-nanocoilloid for sentinel lymph node (SLN)-mapping.

Background: The current gold standard for axillary staging in patients with breast cancer is sentinel lymph node biopsy (SLNB) using radio-guided surgery using radioisotope technetium ( 99m Tc), sometimes combined with blue dye. A promising alternative is fluorescent imaging using ICG.

Methods: In this noninferiority trial, we enrolled 102 consecutive patients with invasive early-stage, clinically node-negative breast cancer. Patients were planned for breast conserving surgery and SLNB between August 2020 and June 2021. The day or morning before surgery, patients were injected with 99m Tc-nanocolloid. In each patient, SLNB was first performed using ICG-fluorescent imaging, after which excised lymph nodes were tested with the gamma-probe for 99m Tc-uptake ex vivo, and the axilla was checked for residual 99m Tc-activity. The detection rate was defined as the proportion of patients in whom at least 1 (S)LN was detected with either tracer.

Results: In total, 103 SLNBs were analyzed. The detection rate of ICG-fluorescence was 96.1% [95% confidence interval (95% CI)=90.4%-98.9%] versus 86.4% (95% CI=78.3%-92.4%) for 99m Tc-nanocoilloid. The detection rate for pathological lymph nodes was 86.7% (95% CI=59.5%-98.3%) for both ICG and 99m Tc-nanocoilloid. A median of 2 lymph nodes were removed. ICG-fluorescent imaging did not increase detection time. No adverse events were observed.

Conclusions: ICG-fluorescence showed a higher (S)LN detection rate than 99m Tc-nanocoilloid, and equal detection rate for pathological (S)LNs. ICG-fluorescence may be used as a safe and effective alternative to 99m Tc-nanocoilloid for SLNB in patients with early-stage breast cancer.