Pathological upstaging of clinical T1 renal cell carcinoma: an analysis of 115,835 patients from National Cancer Data Base, 2004-2013

Clinical staging is vital for treatment decision-making by renal cell carcinoma (RCC) patients. Some RCCs clinically appear T1 on CT, but are actually T3a due to extension into fat or renal vein, causing the tumor to be pathologically upstaged. The objective of this study to determine the rate, survival, and predictors of RCC upstaging, for patients with cT1 disease treated surgically. Using the National Cancer Data Base Participant User File for RCC from 2004 to 2013, we selected AJCC cT1 patients, who underwent surgical resection and whose AJCC pathological T stage (pT) was available. Upstaging was characterized dichotomously-overall (any pT > T1) and pT3a-specific upstaging. Patient and tumor characteristics of those upstaged and not were compared using Chi-squared analyses. Multivariable logistic regression was used to analyze predictors of upstaging, and Cox proportional hazards regression was used to estimate overall survival hazards ratios. Overall upstaging (pT > T1) was observed in 8252 (7.1%) patients, and T3a-specific upstaging was observed in 3380 (5.4%) patients. Patients who were older, male, and had comorbidities, and tumors that were cT1b, underwent RN, and had high Fuhrman grade were at a higher risk of pathological upstaging. Upstaging led to a 40% increased risk of death compared to patients who were not upstaged. The rate of upstaging is not negligible (5-7% of the time), negatively impacts survival, and various patient and tumor characteristics can be used to predict upstaging.