Background
Combining radioactive colloids and a near-infrared (NIR) fluorophore permit preoperative planning and intraoperative localization of deeply located sentinel lymph nodes (SLNs) with direct optical guidance by a single lymphatic tracer. The aim of this clinical trial was to evaluate and optimize a hybrid NIR fluorescence and radioactive tracer for SLN detection in breast cancer patients.
Method
Patients with breast cancer undergoing SLN biopsy were enrolled. The day before surgery, indocyanine green (ICG)-99mTc-Nanocolloid was injected periareolarly and a lymphoscintigram was acquired. Directly before surgery, blue dye was injected. Intraoperative SLN localization was performed by a gamma probe and the Mini-FLARETM NIR fluorescence imaging system. Patients were divided into two dose groups, with one group receiving twice the particle density of ICG and nanocolloid, but the same dose of radioactive 99mTechnetium.
Results
Thirty-two patients were enrolled in the trial. At least one SLN was identified pre- and intraoperatively. All 48 axillary SLNs could be detected by gamma tracing and NIR fluorescence imaging, but only 42 of them stained blue. NIR fluorescence permitted detection of lymphatic vessels draining to the SLN up to 29 hours after injection. Increasing the particle density by two-fold did not yield a difference in fluorescence intensity, median 255 (range 98 – 542) vs. median 284 (90 – 921; P = 0.590), or signal- to- background ratio, median 5.4 (range 3.0 – 15.4) vs. median 4.9 (3.5 – 16.3; P = 1.000), of the SLN.
Conclusion
The hybrid NIR fluorescence and radioactive tracer ICG-99mTc-Nanocolloid permitted accurate pre- and intraoperative detection of the SLNs in patients with breast cancer.