The importance of the eosinophil in head and neck cancer.

In a previous study, we found tumor-associated tissue eosinophilia (TATE) to be a favorable prognostic indicator for squamous cell carcinoma of the head and neck (p less than 0.05). The present expanded study was undertaken to confirm this finding. The pathology of 120 head and neck tumors was examined for histologic features suggestive of poor prognosis. Ten descriptive histopathologic variables, including two malignancy grading scales, were correlated with DNA flow cytometric data and clinical outcome. No correlation was found between the malignancy grading scales and DNA flow cytometric data or clinical outcome. The present expanded study confirmed with greater statistical significance (p less than 0.001) that high-grade TATE is a favorable prognostic indicator for head and neck cancer. Furthermore, high-grade TATE was associated with the absence of distant metastasis (p less than 0.05). Using a stepwise logistic regression analysis of the clinicopathologic variables in the study, high-grade TATE was the most influential variable affecting clinical outcome, followed by border, stage, and perineural invasion. We conclude that the grade of TATE is a significant prognostic indicator for head and neck cancer. The significance and possible role of the eosinophil in the tumor-host interaction are discussed.