Paired-agent imaging as a rapid en face margin screening method in Mohs micrographic surgery.

Area of Science:

• Oncology
• Medical Imaging
• Dermatology

Background:

• Mohs surgery offers high cure rates for non-melanoma skin cancers via 100% margin analysis.
• Current methods are time-intensive, limiting application to smaller, high-risk tumors.
• Paired-agent imaging (PAI) offers rapid screening of excised specimens to identify tumor-positive margins.

Purpose of the Study:

• To evaluate the efficacy of PAI in identifying cancerous margins in a mouse xenograft model.
• To compare PAI with targeted fluorescence alone for diagnostic accuracy and contrast.
• To assess the correlation between PAI metrics and EGFR expression via immunohistochemistry.

Main Methods:

• A mouse xenograft model of human squamous cell carcinoma was used.
• Simultaneous injection of targeted (ABY-029) and untargeted imaging agents prior to resection.
• Fluorescence imaging of excised specimens and en face margins, measuring binding potential (BP) and targeted fluorescence.

Main Results:

• PAI demonstrated superior diagnostic ability and contrast-to-variance ratio (CVR) compared to targeted fluorescence alone.
• Maximum BP achieved 100% accuracy in distinguishing tumor from normal tissue in fresh margin samples.
• PAI metrics showed strong concordance with EGFR immunohistochemistry estimates.

Conclusions:

• PAI reliably distinguishes tumor from normal tissue in fresh en face margins using maximum BP.
• PAI serves as a sensitive screening tool, potentially reducing time spent on pathological assessment.
• This technology can enhance the efficiency of margin evaluation in skin cancer surgery.