Combined renal sinus fat and perinephric fat renal cell carcinoma invasion has a worse prognosis than either alone.

PURPOSE: Recently groups reached differing conclusions when examining the prognostic significance of renal cell carcinoma perinephric and sinus fat invasion. We evaluated the impact of these pathological features on renal cell carcinoma survival and recurrence.

MATERIALS AND METHODS: We identified the pathological and clinical records of 110 patients treated surgically for renal cell carcinoma with extrarenal extension at our institution between 1997 and 2007. Patients with von Hippel-Lindau disease were excluded from study. We used Kaplan-Meier survival curves with the log rank statistic to evaluate differences between groups. Cox logistic regression analysis was used to control for metastatic disease, tumor size and renal vein involvement to determine differences among the groups.

RESULTS: Patients with perinephric plus sinus fat invasion had worse cancer specific survival than those with perinephric or sinus fat invasion alone (p <0.005). There was no difference in cancer specific survival between those with sinus vs perinephric fat invasion (p = 0.248). On multivariate analysis perinephric plus sinus fat invasion was a significant prognostic factor for death from renal cell carcinoma compared to sinus fat invasion alone (p = 0.038).

CONCLUSIONS: Patients with combined renal sinus and perinephric fat invasion had a worse prognosis than those with either alone. Considerations should be made to stage these cases accordingly.