Sentinel lymph node mapping in breast cancer: evaluating the dual-tracer method with indocyanine green and radioisotope (Poster presentation)

Abstract

<h2>Background</h2><p>Indocyanine green (ICG) has the potential to improve sentinel lymph node (SLN) mapping. This current cohort study was designed to assess the value of ICG using a new ICG handheld system with radioisotope (RI) in patients with early breast cancer undergoing SLN biopsy.</p><h2>Methods</h2><p>A prospective self-controlled trial compared the detection efficacies of ICG and RI was conducted. Concordance (ICG and RI-positive cases divided by RI-positive cases) and reverse concordance (ICG and RI-positive cases divided by ICG-positive cases) were documented and adverse event were also assessed.</p><h2>Results</h2><p>Of 69 patients (median age 56.7 (range 33-85), median BMI 22.6 (range 17.0 – 44.5)) enrolled between 2019 and 2021, 71 SLN biopsies were performed. Sixty-one (85.9%) underwent upfront surgery, while ten (14.1%) were given neoadjuvant treatment. Thirty-four breast-conserving surgeries (BCS) (47.9%), 33 mastectomies (46.5%) and four cryotherapies (5.6%) were performed. No adverse event nor skin staining were reported. The SLN identification rate was 87.3% (62/71) for ICG and 95.8% (68/71) for RI (p=0.13). Dual tracer method resulted in 97.2% successful identification, significantly superior to ICG alone (p=0.04, OR 5.0, CI 1.0-24.1) and and was in line with the reported rate of 96.7% (94.3-99.1)¹ by blue dye and RI. Concordance and reverse concordance rates were 89.7% and 98.4%, respectively. A median of 2 lymph nodes was detected by both ICG (range 0 – 6) and IR (range 0 – 5) with no statistical difference (p=0.60). Of 10 cases with 13 metastatic nodes confirmed by histology, both ICG and RI achieved 100% concordance rates. Breast conserving treatments had a higher ICG failure rate compared to mastectomy (21.1% vs 3.0%, p=0.05, OR 8.5, CI 1.0-72.4). In addition, among three cases with prior surgery, two failed ICG SLN identification. Meanwhile, age, BMI, tumour location, multifocality, neoadjuvant treatment, and ICG volume showed no significant correlation with ICG detection rate.</p><h2>Conclusions</h2><p>The combined use of ICG and RI ensures adequate SLN identification without problems known with the use of blue dye, such as skin staining and anaphylaxis. A higher failure rate was noted in patients with breast-conserving treatments for ICG tracing.</p>