Background: Incidental pathological upstaging to pT3a disease can occur after surgical treatment of clinical T1 and T2 Renal Cell Carcinoma (RCC), and upstaged pT3a disease is associated with worsened outcomes. Oncologic and survival outcomes within the pT3a category are heterogeneous. We investigated recurrence and survival outcomes in pT3a disease, and aimed to better categorize this cohort for improvement on current TMN staging. Methods: Multi-center retrospective analysis of patients with renal cell carcinoma (cT1-3aN0M0) from 1987-2016. After initial comparison of outcomes between pT1, pT2 and pT3a, patients were substratified within the pT3a category based on presenting clinical stage. Comparison was drawn between pT1, pT2 and the subdivided pT3a group (cT1 → pT3a, cT2 → pT3a, and cT3a → pT3a). Primary outcome was recurrence free survival (RFS). Secondary outcome was overall survival (OS). Kaplan−Meier (KM) analysis was utilized. Results: 2640 patients were analyzed (2125 cT1, 448 cT2, 67 cT3a, mean follow up 67.8 months). Rate of incidental T3a upstaging from cT1-2 was 14.7%. Compared to pT1-2 disease, patients with incidental pT3a upstaging had higher rate of recurrence (7.5% vs. 29.6%, p < 0.001) and all-cause mortality at last follow up (15.9% vs. 25.4%, p < 0.001). With regards to RFS, when pT3a was subdivided based on presenting clinical stage, significant differences in RFS emerged which aligned differently. Compared to 5 year RFS of pT1 (94.4%), cT1 → pT3a aligned with pT2 (76.6% and 81.2%, p = 0.346) while cT2 → pT3a aligned with cT3a → pT3a 47.4% and 44.0%, p = 0.815). With regards to OS, a similar alignment was noted for 5 year OS after subdivision, where pT1 was 89.9%, while cT1 → pT3a correlated with pT2 (79.8% and 83.1%, p = 0.640) and cT2 → pT3a correlated with cT3a → pT3a 67.0% and 64.2%; p = 0.893). Conclusions: Patients with cT1 → pT3a have outcomes more similar to pT2, than patients with cT2 → pT3a which align more closely to cT3a → pT3a. Future refinements of the TNM staging system for RCC should consider re-grouping cT1 → pT3a into the pT2 group. Further confirmation is requisite.