Outcomes and Predictors of Clinical T1 to Pathological T3a Tumor Up-Staging after Robotic Partial Nephrectomy: A Multi-Institutional Analysis

Purpose: We evaluated the early oncological end point of recurrence-free survival in patients with renal cell carcinoma up-staged from cT1 to pT3a after partial nephrectomy. We also aimed to establish preoperative factors associated with pathological tumor up-staging.Materials and Methods: A prospective database of robotic partial nephrectomy cases performed at 5 academic centers was queried for patients who underwent surgery for a solitary cT1 renal mass. Patients with pT1-2 renal cell carcinoma were compared to those with pT3a tumors to determine the difference in recurrence-free survival. Preoperative factors associated with cT1 to pT3a up-staging were studied using multivariate logistic regression analysis.Results: A total of 1,096 patients underwent robotic partial nephrectomy for a cT1 renal mass. At final pathological evaluation 855 tumors (78.0%) were found to be renal cell carcinoma, of which 41 (4.8%) were up-staged to pT3a. The 24-month recurrence-free survival estimates for pT1-2 and pT3a tumors were 99.2% and 91.8%, respectively (p = 0.003). Multivariate analysis revealed that a high vs low R. E. N. A. L. (radius, exophytic/endophytic, nearness to collecting system or sinus, anterior/posterior and location relative to polar lines) nephrometry score was associated with tumor up-staging (OR 2.97, 95% CI 1.20-7.35, p = 0.02). On separate multivariate analysis increasing tumor diameter (OR 1.66, 95% CI 1.32-2.08, p < 0.001) and hilar location (OR 2.83, 95% CI 1.43-5.61, p = 0.003) were also associated with up-staging.Conclusions: At short-term followup patients with renal cell carcinoma upstaged from cT1 to pT3a have reasonable oncological outcomes after partial nephrectomy. Factors associated with tumor up-staging include high tumor complexity, increasing tumor diameter and hilar location. Further studies are needed to determine the comparative efficacy of partial vs radical nephrectomy for small pT3a tumors.