Consideration for Reclassification of Pathologically Upstaged T3a Renal Cell Carcinomas.

644 Background: Pathological upstaging to pT3a disease can occur after the surgical treatment of clinical T1 and T2 Renal Cell Carcinomas (RCCs), and this upstaging has been previously shown to be associated with poorer outcomes. With an intent to delve deeper into the disparateness in outcomes of pT3a disease, we investigated the survival of patients with an initial clinical stage of cT1, cT2 and cT3a. Methods: Using the National Cancer Database (NCDB), patients with RCC were categorized by pathological and clinical staging of RCC according to the American Joint Committee on Cancer Guidelines (AJCC). The primary outcome was measured as overall survival (OS) at the end of follow up. Five-year survival rates and Kaplan-Meier Analysis assessed the differences between cT1 → pT3a, cT2 → pT2, cT2 → pT3a, and cT3a → pT3a. Multivariable cox regression (MVA) assessed predictors OS with age, sex, ethnicity, Charlson Score, socioeconomic status, geography, tumor size histology and grade, lymph node metastasis, surgical margins, and surgery type (partial versus radical nephrectomy) as covariates. Results: 53908 patients were analyzed (10789 cT1 → pT3a, 22183 cT2 → pT2, 9676 cT2 → pT3a, 11260 cT3a → pT3a, mean follow up 62.3 months). Of all pT3a patients, 64.5% were upstaged from cT1-2. MVA for OS demonstrated Hispanic ethnicity to be protective (hazard ratio [HR]=0.88, P<0.001) and revealed different histologic risks. MVA for OS demonstrated that cT2 → pT3a (HR=1.33, P<0.001, cT1 → pT3a [ref]) and cT3a → pT3a (HR=1.35, P<0.001, cT1 → pT3a [ref]) were associated with worsened OS, and that cT1 → pT3a and cT2 → pT2 (HR=0.96, P<0.052, cT1 → pT3a [ref]) were associated with improved OS. Kaplan-Meier analysis revealed a difference in 5 year overall survival as well (cT1→pT3a 72%, cT2→pT2 77%, cT2→pT3a 61%, and cT3a→pT3a 59%, p < 0.001). Conclusions: Patients with cT1 upstaged to pT3a have similar outcomes to cT2 staged to pT2 and better outcomes than cT2 upstaged with the latter’s outcomes being more like cT3a staged to pT3a. The TNM staging system from AJCC for RCCs should consider these outcomes and adjust the grouping for RCCs accordingly.