Rapid nodal staging of head and neck cancer surgical specimens with flow cytometric analysis

BACKGROUND: Detection of metastatic spread of head and neck cancer to cervical lymph nodes is essential for optimal design of therapy. Undetected metastases lead to mortality, which can be prevented by better detection methods. METHODS: We analysed 41 lymph nodes from 19 patients with oral squamous cell carcinoma (OSCC). Each lymph node was divided in two, one half processed for histopathology and the other half dissociated into single-cell suspension, stained for the carcinoma cell markers cytokeratin 5/8 (CK5/8), epithelial cell adhesion molecule (EpCAM) and epithelial mucin (MUC-1), and analysed with flow cytometry. Flow cytometry data were compared with histopathology performed on serial sections and immunohistochemistry. Six cervical lymph nodes from cancer-free patients were used to establish baseline levels in flow cytometry. RESULTS: Flow cytometry analysis (fluorescence-activated cell sorting; FACS) detected all six metastases confirmed by histopathology as well as the histologically negative nodes. Importantly, among nine sentinel lymph nodes, FACS analysis detected <1% malignant cells in four cases, not found in histopathology. Results from flow cytometry analysis can be obtained within 3 h of the time of biopsy. CONCLUSIONS: We show that flow cytometric analysis of nodal tissue is sensitive and reliable in identifying metastases of OSCC. Flow cytometry is inexpensive and fast, providing a possibility of perioperative diagnostics and immediate treatment planning.