Incidence of Micrometastasis and Isolated Tumour Cells in Clinicopathologically Node-Negative Head and Neck Squamous Cell Carcinoma

Introduction Occult neck node metastasis in head and neck squamous cell carcinoma (HNSCC) in the form of micrometastasis and isolated tumour cell (ITC) often goes unnoticed in the routine pathological examination. This limitation can be overcome by using serial sectioning and immunohistochemistry for detection of micrometastasis and ITC in clinically and pathologically node-negative neck. The primary objective was to determine the incidence of micrometastasis and ITC in the selective neck dissection specimen, whereas to determine the levels of lymph nodes involved, depending upon the site of primary tumour, was the secondary objective. Materials and Methods Lymph nodes from selective neck dissection specimen were subjected to serial sectioning and immunohistochemistry with pan-cytokeratin marker. Incidence of micrometastasis and ITC, site and stage of primary tumours and level of lymph nodes involved were determined. Results In total, 8.8% patients in the study got upstaged after serial sectioning and immunohistochemistry. Tongue and lower alveolar primaries showed the presence of micrometastasis and ITC in neck nodes. All the primary tumours were of pT1 stage. Level IB and II lymph nodes were primarily involved. Conclusion Micrometastasis and isolated tumour cells are found in approximately 9% of cases of early-stage oral cavity squamous cell carcinoma. The predictive factors and clinical significance are still unknown. More prospective trials are required to solve this evolving aspect of HNSCC.