Objective: To assess the prognostic value of microscopic venous invasion (MVI) in a long-term follow-up series.
Patients and method: 255 patients had a radical nephrectomy between 1980 and 1990 for pT1 to pT3b N0 M0 renal cell carcinoma. We reviewed the disease free, specific and overall survival after 183 months of median follow-up. Survival analyses using Kaplan-Meier and Log-rank models for univariate comparisons and Cox proportional hazards model for multivariate analyses were performed. The studied variables were: age, size, side, extracapsular invasion, renal vein invasion, local stage, Fuhrman's grade and MVI.
Results: MVI was found in 74 cases (29%). The MVI was strongly correlated to metastases appearance and survival (p < 0.0001). Multivariate analysis of disease free survival showed the following independent variables: size (p < 0.0001) and Fuhrman's grade (p < 0.0001). For cancer specific survival, the analysis found size (p < 0.0001), age (p = 0.0005), Fuhrman's grade (p = 0.0035) and MVI (p = 0.016) with a relative risk of cancer related death of 2.16. Independent prognostic factors of overall survival were age (p < 0.0001), size (p < 0.0001), MVI (p = 0.015) and Fuhrman's grade (p = 0.045). The relative risk of cancer related death for MVI is 1.82.
Conclusion: It seems that MVI is an independent prognostic factor of survival for patients with pT1 to pT3b N0 M0 renal cell carcinoma.