Objective: To analyze histological factors not routinely assessed as potential prognostic factors in renal cell carcinoma, such as tumor necrosis, microscopic vascular invasion, and sinus fat invasion.
Materials and methods: A retrospective, analytical study was conducted of surgical specimens from 139 patients with localized renal cell carcinoma who underwent nephrectomy from 1993 to 2005. Tumor necrosis, microscopic vascular invasion, and sinus fat invasion were analyzed and compared to the classical factors: TNM classification, Fuhrman grade, and tumor size. For statistical analysis, variables analyzed were categorized as pT1, 2 vs pT3, 4; Fuhrman grade 1, 2 vs 3, 4; tumor size < 7 cm vs >or= 7cm; tumor necrosis vs no tumor necrosis; microvascular invasion of sinus fat vs no invasion. Cancer-specific survival probability and disease-free survival were calculated. A descriptive and analytical statistical analysis was performed using logistic regression for univariate and multivariate analyses. Dependent variables were used to analyze cancer-specific survival rates. Disease-free survival was estimated using a Cox regression model and Kaplan-Meier curves.
Results: In the univariate analysis, all variables analyzed had a significant influence on death for renal cell carcinoma. In the multivariate analysis, the variable having the greatest influence was Fuhrman grade (p = 0,032). The variables significantly influencing disease-free survival, estimated by the Cox method, were the pT stage (p = 0.038) and Fuhrman grade (p = 0.048).
Conclusions: In patients with clinically localized renal cell carcinoma undergoing nephrectomy, pT stage and Fuhrman grade are the most important prognostic factors for survival and disease-free survival. Tumor necrosis, microscopic vascular invasion, and sinus fat invasion are prognostic factors for death from renal carcinoma which are associated to TNM classification, Fuhrman grade, and tumor size.