Microvascular tumour invasion in renal cell carcinoma: the most important prognostic factor.

OBJECTIVE: To evaluate the role of microvascular invasion (MVI) in the primary lesion for predicting tumour behaviour in patients with renal cell carcinoma (RCC), as reliable clinical prognostic factors would be very valuable.

PATIENTS AND METHODS: MVI was assessed in 230 patients with clinically localized RCC (stages T1-4NxM0) who had a radical nephrectomy and/or nephron-sparing surgery. The median (range) follow-up was 48 (3-130) months. The impact of MVI on disease progression and its correlation with clinical and histopathological factors was analysed, including whether patients were symptomatic or not at presentation, Fuhrman nuclear grade, tumour size, pathological stage and lymph node metastasis. Regression analyses and survival curves were used to determine if MVI was associated with the prognosis of RCC.

RESULTS: There was MVI in 59 patients (26%); of these, 46% developed disease recurrence. Among the 171 patients with no MVI, only 11 (6%) had tumour recurrence. MVI was associated with tumour diameter, nuclear grade, pathological stage, lymph node metastasis and the presence of sarcomatous elements in the tumour. Multivariate analysis showed that MVI was an independent predictor of disease recurrence and the most important factor related to death.

CONCLUSION: MVI is an independent predictor of prognosis in patients with RCC.