Role of near-infrared fluorescence imaging in the resection of metastatic lymph nodes in an optimized orthotopic animal model of HNSCC

ObjectivesTo study the role of near-infrared fluorescence imaging in the detection and resection of metastatic cervical lymph nodes in head and neck cancer.Materials and methodsCAL33 head and neck cancer cells of human origin were implanted in the oral cavity of nude mice. The mice were followed up after tumor resection to detect the development of lymph node metastases. A specific fluorescent tracer for αvβ3 integrin expressed by CAL33 cells was injected intravenously in the surviving mice between the second and the fourth month following tumor resection. A near-infrared fluorescence-imaging camera was used to detect tracer uptake in metastatic cervical lymph nodes, to guide of lymph-node resection for histological analysis.ResultsLymph node metastases were observed in 42.8% of surviving mice between the second and the fourth month following orthotopic tumor resection. Near-infrared fluorescence imaging provided real-time intraoperative detection of clinical and subclinical lymph node metastases. These results were confirmed histologically.ConclusionNear infrared fluorescence imaging provides real-time contrast between normal and malignant tissue, allowing intraoperative detection of metastatic lymph nodes. This preclinical stage is essential before testing the technique in humans.