Prognostic Value of Capsular Invasion for Localized Clear-Cell Renal Cell Carcinoma

Background: The impact of capsular invasion on the survival of patients undergoing surgery for renal cell carcinoma (RCC) has attracted little attention in the literature and remains controversial. Objectives: To evaluate the value of capsular invasion, without perirenal fat invasion, on the prognosis of patients with localized clear-cell RCC. Design, setting, and participants: Between 1984 and 2007, we retrospectively reviewed the records of 317 consecutive patients with localized clear-cell RCC (pT1-T2N0M0) who underwent radical nephrectomy or nephron-sparing surgery at our institution. Overall, 299 patients were eligible for the study. We analyzed clinical (presentation and body mass index [BMI]) and pathologic (tumor size, Fuhrman nuclear grade, collecting system invasion, microvascular invasion, and capsular involvement) parameters. Measurements: Recurrence-free survival (RFS) and cancer-specific survival (CSS) were investigated using the Kaplan-Meier method, and the Cox regression model was used to determine the significant prognostic factors based on multivariate analysis. Results and limitations: Renal capsular invasion was observed in 106 of 299 patients (35.5%). Capsular invasion had a statistically significant association with age, symptomatic presentation, tumor diameter, pathologic stage, collecting system invasion, and microvascular invasion. The mean follow-up was 60.5 mo (range: 1-249). The 5-yr RFS and CSS rates for tumors with capsular invasion were significantly lower compared with rates for tumors without invasion (77.7% vs 92.3% and 85.5% vs 95.7%, respectively; p = 0.0004). Multivariate analysis showed that BMI (hazard ratio [HR] = 0.19), stage (HR = 2.45), and capsular invasion (HR = 3.36) were independent prognostic factors of disease recurrence. With respect to CSS, BMI (HR = 0.20), tumor size (HR = 1.13), and capsular invasion (HR = 4.03) were the factors related to death. Nevertheless, we recognize that these findings may be limited by the study's retrospective, single-institution design. Conclusions: Our findings suggest that capsular invasion is associated with poor survival in patients with localized clear-cell RCC.