The significance of immunohistochemically demonstrated nodal micrometastases in patients with squamous cell carcinoma of the head and neck

Objectives/Hypothesis: Patients with primary squamous cell carcinoma of the head and neck have a relatively high risk of occult lymph node metastases. Pathological demonstration of these metastases may be difficult, and the detection of such occult metastases may identify patients who are at an increased risk for early recurrence or reduced survival. Immunohistochemistry may be applied in the identification of occult metastases that may be missed on routine (H&E) histological examination. The aim of the study is to determine the prevalence and prognostic significance of immunohistochemically identified micrometastases in squamous cell carcinoma of the head and neck. Study Design: A retrospective analysis of neck dissection specimens having no evidence of metastatic disease. Methods: Lymph nodes from neck dissections performed on 10 patients with squamous cell carcinoma of the head and neck without conventional histological evidence of nodal metastases were subsequently stained for cytokeratins by the monoclonal antibody cocktail AE1/AE3 to detect micrometastases. Results: Occult micrometastases were found in the lymph nodes 5 of 10 patients examined. There was no association between the site of primary tumor, or T tage, and the presence of occult metastases. Three of five patients found to have occult metastases developed recurrence in the neck, whereas only one of five patients with no evidence of micrometastases had regional recurrence. There was no significant discrepancy in the patient survival rate. Conclusions: Metastatic tumor cells are frequently present in lymph nodes, even in patients without histological evidence of nodal metastases by conventional methods. The presence of micrometastases may identify patients at increased risk for recurrence and may indicate poorer prognosis. The true clinical significance of these occult metastases will be determined by a long-term follow-up.