Evaluation of the Prognostic Significance of Microvessel Count and Tumor Size in Renal Cell Carcinoma

BACKGROUND: We analyzed the significance of tumor microvessel count and tumor size as prognostic factors for renal cell carcinoma (RCC). METHODS: T criteria (local invasion), M criteria (distant metastasis), macrovenous invasion, histological grade, cell type, tumor size, and tumor microvessel count were investigated as prognostic factors in 62 patients with RCC. Microvessel density was evaluated by immunohistochemical staining of the endothelial cells. RESULTS: No significant correlation was found between tumor size and the other prognostic factors. Analysis of the survival rate based on tumor size revealed that patients with a small tumor tended to show a good prognosis, but no significant difference was found in the prognosis between medium-sized and large-sized tumor groups. Analysis of all patients revealed that M criteria, macrovenous invasion, cell type and microvessel count were significant factors and that in 37 patients with low-stage tumors, the only significant prognostic factor was microvessel count (P=0.003). CONCLUSION: Tumor size cannot be readily justified as a determinant of prognosis in patients with medium- or large-sized tumors. In patients with low-stage tumors, microvessel count served as the only significant determinant for prognosis. When the patients were considered as a whole, microvessel count, M criteria, macrovenous invasion and histological grade were significant prognostic factors.