Trial Information

Near-Infrared Fluorescent Sentinel Lymph Node Mapping for Breast Cancer

The standard of care in breast cancer surgery includes identification and assessment of the
sentinel lymph node (SLN). At the present time, SLN mapping utilizes a gamma ray-emitting
radiotracer and/or a blue dye. Radiotracers provide sensitive detection of SLNs, but require
involvement of a nuclear medicine physician, vary widely in transit time depending on the
agent employed, can be difficult to localize with a handheld gamma probe, and expose both
patient and caregivers to ionizing radiation. Blue dyes, such as isosulfan blue, cannot be
seen easily through skin and fat, but can aid in definitive identification of the SLN when
the handheld gamma probe gives ambiguous results. Finally, the learning curve associated
with expertise in the SLN procedure is quite long using currently available techniques.

In this 12-patient pilot study, we are testing a new intraoperative imaging system that we
developed for image-guided surgery. The imaging system uses invisible, near-infrared (NIR)
light to visualize lymphatic flow and to identify the SLN. The imaging system makes no
contact with the patient and can display surgical anatomy simultaneously with NIR
fluorescence.

All patients will receive the standard of care for SLN mapping, namely technetium-99m sulfur
colloid lymphoscintigraphy. In addition, patients will be injected with indocyanine green
(ICG) diluted in human serum albumin (HSA). ICG is already FDA approved for other
indications and is used in this study at 400-fold to 2000-fold lower than the typical
clinical dose. Dilution into HSA improves the brightness of ICG by over 3-fold, making it an
excellent tracer for lymphatic flow.

The purpose of this pilot study is to determine whether the ergonomics of the imaging system
interfere with typical clinical workflow during breast cancer surgery. A secondary goal is
to optimize the imaging parameters (light levels, exposure time, etc.) associated with
identification of the SLN.