Intraoperative fluorescence imaging to localize tumors and sentinel lymph nodes in rectal cancer

Abstract

Tumor involvement at the resection margin remains the most important predictor for local recurrence in patients with rectal cancer. A careful description of tumor localization is therefore essential. Currently, endoscopic tattooing with ink is customary, but visibility during laparoscopic resections is limited. Near-infrared (NIR) fluorescence imaging using indocyanine green (ICG) could be an improvement. In addition to localize tumors, ICG can also be used to identify sentinel lymph nodes (SLNs). The feasibility of this new technique was explored in five patients undergoing laparoscopic low anterior resection for rectal cancer. Intraoperative tumor visualization was possible in four out of five patients. Fluorescence signal could be detected 32±18 minutes after incision, while ink could be detected 42 ± 21 minutes after incision (p = 0.53). No recurrence was diagnosed within three months after surgery. Ex vivo imaging identified a mean of 4.2 ± 2.7 fluorescent lymph nodes, which were appointed SLNs. One out of a total of 83 resected lymph nodes contained a micrometastasis. This node was not fluorescent. This technical note describes the feasibility of endoscopic tattooing of rectal cancer using ICG:nanocolloid and NIR fluorescence imaging during laparoscopic resection. Simultaneous SLN mapping was also feasible, but may be less reliable due to neoadjuvant therapy.

Key words:

• Fluorescence imaging
• rectum
• rectal cancer
• feasibility study
• surgery

Acknowledgments

We thank KARL STORZ GmbH & Co. KG for supplying the laparoscopic near-infrared imaging system.

Declaration of interest: J.V. Frangioni is currently CEO of the Curadel Companies (Curadel, Curadel ResVet Imaging and Curadel Surgical Innovations). He, his wife and children own equities in Curadel, which is commercializing FLARE technology. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Disclaimer: John V. Frangioni, M.D., Ph.D.: FLARE™ technology is owned by Beth Israel Deaconess Medical Center, a teaching hospital of Harvard Medical School. Dr. Frangioni has started 3 for-profit companies, Curadel, Curadel ResVet Imaging, and Curadel Surgical Innovations, which has optioned FLARE™ technology for potential licensing from Beth Israel Deaconess Medical Center.

Source: This work was supported by the Dutch Cancer Society, grant no. UL2010-4732. This study was performed within the framework of the Center of Translational Molecular Medicine (project MUSIS, Grant 03O-202-04).