Insignificance of Perirenal Fat Invasion in Small Renal Masses

Objective: To evaluate oncologic outcomes in clinical T1a tumors which remain pathological T1a compared to tumors which were upstaged to pathologic T3a due to perirenal fat invasion. Methods: A retrospective database was created of all patients with solitary clinical T1a renal masses who underwent surgical intervention for renal cell carcinoma from 2000 to 2012 at a single institution. Patients with pathologic T1a renal cell carcinoma were compared to those upstaged to T3a for differences in overall mortality and disease-free survival using Kaplan-Meier and Cox Proportional Hazards models. Results: Of the 218 patients with cT1a, 24 (11%) were upstaged to pathologic T3a. Kaplan-Meier survival estimates revealed there to be no statistical differences in overall mortality. Multivariate regression analysis revealed that only age, histology, and Charlson index score were predictors of overall survival. Hazard ratios for ≥ 65 years of age, clear cell histology, and Charlson index score per point were 2.2 times (95% CI:1.38-3.57,p