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.