Rapid tumor margin analysis using paired-agent imaging to guide Mohs micrographic surgery

Thorough tumor resection is crucial for successful treatment of squamous cell carcinomas (SCCs) because positive surgical margins are associated with poor patient prognosis. Current methods of margin analysis, however, are limited by inefficient pathological read-times that increase exponentially with tissue size. Here, a fluorescence paired-agent imaging (PAI) approach is presented to identify regions of tumor burden in whole, thick tissue margins to act as a rapid screening tool and help focus pathological evaluation. The approach was applied to mouse models of head and neck SCC, and positive tumor burden was detected and localized in deep tissue margins up to 1.3 mm thick. Serial sections with hematoxylin and eosin and Epidermal Growth Factor Receptor (EGFR)-immunostaining demonstrated good correlation with binding potential (BP: proportional to targeted biomolecule concentration) maps generated from PAI fluorescence slices and confirmed the presence of positive margins suggested by high intensity regions in the whole tissue BP maps. Findings support the use of PAI as a rapid screening method for detecting regions of tumor burden in large, en face tumor margin sections similar to Mohs micrographic surgery.