Sentinel node biopsy in cancer of the oral cavity

Sentinel lymph node biopsy represents a less invasive technique for detecting subclinical lymphatic metastases in patients with a known primary malignancy. This procedure was developed to address the management of the lymphatics for cutaneous lesions, especially malignant melanoma. For melanoma, lymphatic drainage patterns are very unpredictable, and the therapeutic value of extensive formal lymphadenectomies remains controversial. The technique is increasingly being applied to other malignancies. Multiple small patient series have been published evaluating the application of lymphatic mapping and sentinel lymph node biopsy to cancer of the oral cavity. The technique requires the selection of patients without clinical or radiologic evidence of gross lymphatic cancer who are at risk for subclinical metastases. Subsequently, primary tumors are injected with a radioactive tracer, followed by radiologic imaging, and then gamma probe-guided lymph node excision through a small incision. Rigorous serial sectioning and immunohistochemistry is essential. Sentinel lymph node biopsy has not yet been validated as safe for oral cavity cancer, and a multi-institutional trial is currently completing accrual to correlate the histopathologic results of sentinel lymph node biopsy and subsequent selective neck dissection. The goal is to establish the predictive value of the less invasive procedure relative to formal lymphadenectomy. In this article, the authors describe the details of their surgical technique for sentinel lymphadenectomy as applied to oral squamous cell carcinomas.