Prognostic Value of Tumor Angiogenesis and Microvascular Invasion in Renal Cell Carcinoma

Abstract

Purpose: This study was performed to evaluate the impact of microvessel density(MVD), a reflection of tumor angiogenesis, and microvascular invasion(MVI) on the prognosis of patients with renal cell carcinoma(RCC). Materials and Methods: Formalin-fixed, paraffin-embedded tissue sections of RCC from 81 patients who had undergone radical nephrectomy were stained immunohistochemically for CD34, which decorate endothelial cells, in order to assess MVD and MVI. The immunostaining results of MVD and MVI were compared with the clinicopathological variables. Results: Twenty-two patients had either synchronous or metachronous metastases and fourteen patients died during the follow-up. MVD was significantly correlated with only metastasis(synchronous or metachronous; p=0.020). MVI was significantly correlated with tumor size(p=0.005), TNM stage(p＜0.001), T stage(p＜0.001), M stage(p=0.001), and metastasis(synchronous or metachronous; p=0.007). MVD was not significantly associated with MVI(p=0.232). The survival rate of patients with higher MVD or MVI-positive tumors was significantly lower than that of patients with lower MVD or MVI-negative tumors, respectively(p＜0.0001, p=0.0002). Multivariate analyses indicated that tumor size, M stage and MVI were independent prognostic factors for cancer-specific survival. MVD was not an independent factor. Conclusions: MVD and MVI were associated with metastasis and a worse prognosis in RCC, which suggests that tumor angiogenesis and MVI may play an important role in the progression of RCC. MVI was an independent prognostic factor for cancer-specific survival.