Prognostic impact of lymph node micrometastasis in oral and oropharyngeal squamous cell carcinomas.

BACKGROUND The purpose of this study was to determine the role of lymph node micrometastasis in oral and oropharyngeal cancers. METHODS We investigated the presence of micrometastases by cytokeratin immunohistochemical staining in 54 patients with node-negative oral and oropharyngeal carcinomas. RESULTS The positive rate of cytokeratin expression was 13.0% (7 of 54 patients). The incidence of micrometastasis was significantly higher in patients with more invasive tumors (p < .001) and larger tumor size (p = .034). The 5-year disease-specific (DS) survival rate significantly correlated with micrometastasis, margin involvement, and depth of invasion in the univariate analyses. Multivariate Cox regression analysis confirmed a significant association between the 5-year DS survival rate and micrometastasis (hazard ratio [HR] = 7.89; 95% confidence interval [CI] = 1.09-57.14; p = .041) and margin involvement (HR = 11.68; 95% CI = 1.22-111.75; p = .033). CONCLUSION Micrometastasis was significantly correlated with the depth of invasion and tumor size in oral and oropharyngeal cancers. Furthermore, micrometastasis was associated with adverse outcomes. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1777-E1782, 2016.