Fluorescence-Guided Surgery

Three major modes of cancer therapies, surgery, radiation and chemotherapy, have been the mainstay of modern oncologic therapy. To minimize side effects, molecular targeted cancer therapies including armed antibody therapy have been developed with limited success. In this study, we developed a new type of molecular targeted cancer therapy, photoimmunotherapy (PIT), employing a target-specific photosensitizer based on a near infrared (NIR) phthalocyanine dye, IR700, conjugated to monoclonal antibodies (MAb) targeting epidermal growth factor receptors (EGFR). Cell death was induced immediately only upon irradiating, MAb-IR700 bound, target cells with NIR light. In vivo tumor shrinkage after irradiation with NIR light was observed only in target EGFR-expressing cells. The MAb-IR700 conjugates were most effective when bound to the cell membrane, producing no phototoxicity when not bound, suggesting a different mechanism for PIT compared with conventional photodynamic therapies. Target selective PIT enables treatment of cancer based on MAb binding on the cell membrane.

Optical imaging using near-infrared (NIR) fluorescence provides new prospects for general and oncologic surgery. ICG is currently utilised in NIR fluorescence cancer-related surgery for three indications: sentinel lymph node (SLN) mapping, intraoperative identification of solid tumours, and angiography during reconstructive surgery. Therefore, understanding its advantages and limitations is of significant importance. Although non-targeted and non-conjugatable, ICG appears to be laying the foundation for more widespread use of NIR fluorescence-guided surgery. Copyright © 2011 Wiley-Liss, Inc.