Characterizing the detection threshold for optical imaging in surgical oncology

Area of Science:

• Oncology
• Medical Imaging
• Molecular Diagnostics

Background:

• Optical imaging is increasingly used in surgery for cancer resection.
• The sensitivity of fluorescence imaging for detecting minimal residual disease requires characterization.

Purpose of the Study:

• To determine the minimum number of cancer cells detectable by antibody-based fluorescence imaging.
• To assess the sensitivity of cetuximab-IRDye800CW for detecting various cancer cell lines.

Main Methods:

• In vitro incubation of four cancer cell lines (2LMP, COLO-205, MiaPaca-2, SCC-1) with cetuximab-IRDye800CW.
• Subcutaneous implantation of serially diluted cancer cells in mice.
• Imaging of tumors using Pearl Impulse and Xenogen IVIS 100 systems.
• Scatchard analysis to determine receptor density and kinetics.

Main Results:

• Fluorescence imaging detected a minimum of 4.2 x 10^4 to 9.5 x 10^4 2LMP cells, 1.9 x 10^5 to 4.5 x 10^5 MiaPaca-2 cells, and 2.4 x 10^4 to 6.7 x 10^4 SCC-1 cells.
• COLO-205 cells were not identifiable under tested conditions.
• Higher epidermal growth factor receptor (EGFR)-mediated uptake of cetuximab correlated with improved detection sensitivity.

Conclusions:

• Cetuximab-IRDye800CW fluorescence imaging demonstrates potential for sensitive detection of subclinical cancer cells.
• The findings support the clinical utility of this technique for localizing minimal disease in surgical settings.