Abstract P3-01-01: Fluorescence navigation system using indocyanine green (ICG) instead of radioisotope for sentinel lymph node (SLN) biopsy in early breast cancer

Abstract

Abstract Background: Dual localisation methods with blue dye and radioisotope are commonly employed for SLN identification but potential drawbacks include allergic reactions, staining of cutaneous/surgical breast tissue, radiation exposure and mandatory licencing. A majority of studies have reported near 100% identification rates using the fluorescent tracer ICG in combination with standard tracer agents. A feasibility study (ICG-10) has confirmed high sensitivity of ICG fluorescence mapping for SLN detection in early breast cancer with 95% of nodes both blue and fluorescent. This follow-on study has specifically evaluated a combination of ICG with blue dye for SLN localization. Methods: As an observational cohort study, 50 consecutive patients (49 female; 1 male) with core biopsy proven unilateral invasive (37 cases) or non-invasive (13 cases) breast cancer underwent SLN biopsy with blue dye and ICG. All patients were clinically and sonographically node negative. Axillary surgery (SLN biopsy) followed neoadjuvant chemotherapy in 5 patients (10%). The median patient age was 48 years and for primary surgical patients median tumor size was 19mm. Patients received a dual peri-areolar/intradermal injection of blue dye [2ml 2.5% Patent Blue] and ICG [2mls 0.5%] after induction of anaesthesia. The number of sentinel nodes for each patient was recorded numerically and whether blue, fluorescent or both. Subcutaneous lymphatics were visualised with a photodynamic eye camera and nodal and procedural detection rates calculated for ICG alone and in combination with blue dye. Results: Final analysis was performed on a total of 87 nodes retrieved from 50 patients with an average nodal count of 1.8 per patient (range 1 – 4). Eighty-four nodes were blue and fluorescent and 3 nodes fluorescent only with no harvesting of non-blue, non-fluorescent nodes. At least one transcutaneous lymphatic channel was visible in all cases. Nodal detection rates for ICG alone and combined with blue dye were 100% (87/87) and 96% (84/87) respectively. Metastases (>0.2mm) were present in 18 nodes which were all blue and fluorescent and a total of 10 patients had at least one positive node (node positivity rate = 20%). The procedural detection rate was 96% (48/50) for blue dye and 100% (50/50) for ICG with 2 patients having fluorescent only nodes which were deemed sentinel (4%). No serious adverse reactions were noted. Conclusion: ICG fluorescence navigation system permits real-time visualization of lymphatic tissues and provides an additional dimension to SLN biopsy using methodology which is sensitive, valuable and safe. These results confirm accuracy of ICG fluorescence for SLN identification with nodal sensitivity of 96% for a combination of blue dye and ICG. With further refinements of the technique, use of ICG as a sole tracer may be possible agent without concerns about excessive nodal yield but improved patient convenience and costs. Citation Format: Benson JR, Pitsinis V, Provenzano E, Wishart GC. Fluorescence navigation system using indocyanine green (ICG) instead of radioisotope for sentinel lymph node (SLN) biopsy in early breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-01-01.