Prognostic significance of microvascular invasion in localized renal cell carcinoma

The treatment of localized and even advanced renal cell carcinoma (RCC) is radical nephrectomy. However, 30% of these patients progress after radical nephrectomy. Prognostic factors are needed in order to determine the course of disease in patients undergoing radical nephrectomy. The aim of this study is to study the prognostic significance of microvascular invasion (MVI) in patients who had undergone radical nephrectomy for localized RCC.

Between June 1989 and February 1999, pathologic sections of the specimens from 41 patients without metastases, nodal involvement or macroscopic venous involvement were investigated for MVI.

MVI was observed in 17% of the patients. MVI was related to the grade of the tumor and tumor size (p = 0.032, p = 0.017). In sarcomatoid-type RCC, MVI was more common than in other histologic types (p = 0.003). After a median follow-up of 48 months, the progression rate was 29% in patients with MVI and 17% without MVI (p = 0.001). Median progression time was 3 months in those with MVI and 41 months with no MVI (p = 0.01). The survival rate decreased from 85 to 70% in patients with MVI during a median follow-up of 48 months (p = 0.031). In multivariate analysis, MVI was not found to be an independent prognostic factor.

Although MVI is closely related to progression and prognosis, in multivariate analysis it was not found to be an independent prognostic factor in localized RCC. We conclude that MVI should also be evaluated together with tumor grade in predicting the prognosis of patients with localized RCC.