Multivariate Cox regression identified five independent predictors of 5-year OS: American Joint Committee on Cancer stage (HR = 1.347, 95% CI: 1.209-1.510), lymph node metastasis (HR = 4.698, 95% CI: 3.282-8.994), tumor differentiation grade (HR = 1.235, 95% CI: 1.105-1.276), microvessel density (HR = 1.089, 95% CI: 1.023-1.159), and Vascular Endothelial Growth Factor (VEGF) expression (HR = 2.451, 95% CI: 1.127-6.372). This evidence concerns the gene VEGFA and metastatic malignant neoplasm in the lymph nodes.