Objective: Microscopic venous invasion (MVI) is characterized by local destruction of the endothelium by a tumor. The prognostic value of MVI in renal cell carcinoma (RCC) is not well established.
Materials and methods: From 1980 until 1990, 255 patients (169 men and 86 women), aged 16-87 (mean 60) years were treated by radical nephrectomy for N0M0 RCC. There were 9 pT1, 163 pT2, 30 pT3a, 34 pT3b, and 19 pT3ab (TNM 1992). The median follow-up time was 74 months. MVI was determined by a double-blind histological study with immunohistochemical staining.
Results: MVI was noted in 74 patients (29%). MVI significantly increased metastatic progression (p = 0.003). Only stage and Fuhrman's grade were significant factors for metastatic progression in a multivariate analysis. MVI decreased the actuarial survival rates at 1 year (p = 0.01), but not significantly at 5 and 10 years. MVI and non-MVI survival curves were statistically different with the Peto/Wilcoxon (p = 0.04) and Gehan/Wilcoxon (p = 0.03) tests, but not with the log rank test (p = 0.06). MVI decreased survival in cases with a tumor size of 10 cm or more, capsular invasion, macroscopic venous invasion, stage pT3ab, sarcomatoid cell carcinoma and Fuhrman's grade IV. Only the stage was a significant factor for survival in a multivariate analysis.
Conclusion: In RCC, MVI is related to cancer progression and survival, but probably not as an independent prognostic factor.