Effective fluorescence-guided surgery of liver metastasis using a fluorescent anti-CEA antibody

Background and Objectives: Delineation of adequate tumor margins is critical in oncologic surgery, particularly in resection of metastatic lesions. Surgeons are limited in visualization with bright-light surgery, but fluorescence-guided surgery (FGS) has been efficacious in helping the surgeon achieve negative margins. Methods: The present study uses FGS in a mouse model that has undergone surgical orthotopic implantation (SOI) of colorectal liver metastasis tagged with green fluorescent protein (GFP). An anti-CEA antibody conjugated to DyLight 650 was used to highlight the tumor. Results: The fluorescent antibody clearly demarcated the lesion at deeper tissue depth compared to GFP. Fluorescence of the anti-CEA-DyLight650 showed maximal tumor-to-liver contrast at 72 hr. Fifteen mice underwent bright-light surgery (BLS) versus FGS with GFP versus FGS with anti-CEA-DyLight650. Mice that underwent FGS had a significantly smaller area of residual tumor (P < 0.001) and significantly longer overall survival (P < 0.001) and disease-free survival (P < 0.001). Within the two FGS groups, mice undergoing surgery with anti-CEA-DyLight650 improved survival compared to only GFP labeling. Conclusions: In the present report, we demonstrate that an anti-CEA antibody conjugated to a DyLight 650 nm dye clearly labeled colon cancer liver metastases, thereby enabling successful FGS. J. Surg. Oncol. 2016;114:951–958.