Application of near infrared fluorescence imaging with indocyanine green in sentinel node biopsy for cN0 oral carcinoma

Objective To evaluate the feasibility and validity of near infrared fluorescence imaging with indocyanine green in sentinel node biopsy for cN0 oral carcinoma. Methods Thirty cases of previously untreated oral carcinoma staged cT1-3N0M0 were enrolled in this study. 1 ml of indocyanine green (25 mg/5 ml) was injected both around the primary tumor in a 4 quadrant pattern and in the base of the tumor before skin incision. After elevation of the platysma flap and posterior retraction of the sternocleidomastoid muscle, fluorescence images were taken with a near infrared fluorescence detector until the hotspots were captured, then the hotspot lymph nodes were removed. Lymph nodes identified with fluorescent hotspots and verified in vivo were defined as sentinel nodes, and they were harvested and sent together with neck dissection specimen for pathologic study. Results Sentinel nodes were successfully harvested in all 30 cases. The number of sentinel nodes per case varied from 1 to 9, with an average number of 3.4. Routine pathology demonstrated that occult metastasis was exclusively found in the sentinel nodes in 5 cases (16.67%), and all the other lymph nodes were free from metastasis. No tracer associated adverse effects occurred in this series. Conclusion Near infrared fluorescence imaging with indocyanine green has a high detection rate in sentinel node biopsy for cN0 oral/oropharyngeal carcinoma and the sentinel nodes can evaluate the cervical metastatic status accurately. It is an easy, feasible and promising method, which is worthy of further investigation. Key words: Oral neoplasms; Sentinel lymph node biopsy; Spectroscopy, near-infrared; Spectrometry, fluorescence; Indocyanine green