Background: The objective of the present study was to investigate the significance of microscopic venous invasion (MVI) as a prognostic factor for patients with renal cell carcinoma (RCC) who underwent radical surgery.
Methods: The study included a total of 157 consecutive patients with non-metastatic RCC who underwent radical surgery between January 1986 and December 2002. The median follow-up period was 45 months (range 6-162 months). Microscopic venous invasion was defined by the presence of a cancer cell in blood vessels based on the examination of hematoxylin-eosin stained specimens. Other prognostic variables were assessed by multivariate analysis to determine whether there was a significant impact on cancer-specific and recurrence-free survivals.
Results: Microscopic venous invasion was found in 70 patients, and of this number, 17 (24.7%) developed a tumor recurrence and 12 (17.1%) died of cancer progression, while only six (6.9%) of the remaining 87 patients without MVI presented with disease-recurrence and three (3.5%) died of cancer. Among the factors examined, the presence of MVI was significantly associated with age, mode of detection, tumor size, pathological stage and tumor grade; however, only pathological stage was an independent predictor for disease-recurrence, and none of these factors were available to predict cancer-specific survival in multivariate analyses. In 120 patients with pT1 or pT2 disease, MVI was noted in 36 patients. In this subgroup, recurrence-free survival rates in patients with MVI were significantly lower than those in patients without MVI, and MVI was the only independent prognostic predictor for disease-recurrence in a multivariate analysis.
Conclusion: Microscopic venous invasion is not an independent prognostic factor in patients with non-metastatic RCC who underwent radical surgery; however, it could be the only independent predictor of disease-recurrence after radical surgery for patients with pT1 or pT2 disease.