Session: MP47: Kidney Cancer: Localized: Surgical Therapy II
MP47-17: Single Center Comparison of Radiographic and Morphometric Characteristics and Outcomes in T3a Pathologically Upstaged and Non-Upstaged Renal Cell Carcinoma
Introduction: A significant portion of patients presenting with Stage 1-2 Renal Cell Carcinoma (RCC) are pathologically upstaged to Stage 3 following surgery. This is due to previously undetected extension into the renal venous system, perirenal or renal sinus fat, or collecting system. Improved detection of potential T3 upstaging may prompt changes in disease management and may impact patient survival. We sought to compare pathologically upstaged and non-upstaged T3a RCC cases to identify characteristics of upstaged masses, predictors of T3a disease, and impact on oncological outcomes. Methods: We conducted a single center retrospective analysis of patients with pathologic T3a RCC who underwent surgical intervention. The cohort was divided into a group of patients with masses which were upstaged, (cT1-cT2/pT3a) and a group with masses preoperatively identified as cT3a (non-upstaged, cT3a/pT3a) for descriptive and outcomes analyses. We sought to delineate proportion of underdiagnosed pT3a RCC, location of upstaged disease, and predictors of upstaging. Outcomes were overall survival (OS) and recurrence-free survival (RFS). Multivariate analyses (MVA) were performed to identify predictors of T3a invasion site and outcomes. Kaplan Meier survival analyses (KMA) were performed to compare survival outcomes. Results: We analyzed 185 patients, of which 120 (64.9%) were upstaged and 65 (35.1%) were non-upstaged. When compared to non-upstaged masses, upstaged masses were significant for smaller size (6.8 cm vs 8.2 cm, p=0.008), lower RENAL score (8.7 vs 9.9, p<0.001), less hilar involvement (29.2% vs 86.2%, p<0.001), and increased exophyticity (41.7% vs 23.1%, p=0.011). On pathology, upstaged masses had greater proportions of perirenal fat invasion (53.3% vs 33.8%, p=0.011), but less venous system (44.2% vs 78.5%, p<0.001) and sinus fat invasion (35.8% vs 63.1%, p<0.001) compared to non-upstaged masses. RENAL domains R, E, and L were independent predictors for T3a disease foci (OR=0.053-7.70, p=0.001-0.042). MVA demonstrated that non upstaged cT3a RCC had a higher risk of recurrence (HR=2.01, p=0.043). KMA noted better RFS in upstaged patients compared to non-upstaged patients (80.8% vs 75.4%, p=0.002). Conclusions: Pathologically upstaged T3a RCC is associated with distinct morphology and invasion patterns, and improved recurrence free survival when compared to non-upstaged T3a RCC. RENAL domains can aid in identifying masses with upstaging potential. SOURCE OF Funding: UC San Diego Summer Research Fellowship
