Predictive factors and oncological outcomes of pathological T3a upstaging in patients with clinical T1 renal cell carcinoma undergoing partial nephrectomy

To investigate predictive factors and oncological outcomes of pathological T3a upstaging in renal cell carcinoma patients who were initially diagnosed as clinical T1 and treated with partial nephrectomy.The clinical records and survival data of 1617 patients, who had undergone partial nephrectomy for clinical T1 renal cell carcinoma at Tokyo Women's Medical University, Tokyo, Japan between January 2011 and December 2020, were analyzed retrospectively.Of 1617 clinical T1 renal cell carcinoma patients who underwent partial nephrectomy, 28 (1.73%) had pathological T3a upstaging. In the multivariable analysis for pathological T3a upstaging using logistic regression models, male sex and clinical T1b were significant factors associated with pathological T3a upstaging (male sex: odds ratio = 5.07, 95% confidence interval: 1.18-21.8, clinical T1b: odds ratio = 8.36, 95% confidence interval: 3.56-19.6). The Kaplan-Meier method of the recurrence-free survival showed shorter recurrence-free survival in patients with pathological T3a upstaging than in those with pathological T1 (P < 0.0001). In the multivariable analysis using Cox proportional hazards regression models, pathological T3a upstaging was no longer significantly associated with recurrence-free survival after adjustment for other pathological factors (hazard ratio = 1.59, 95% confidence interval: 0.58-4.36). In a sensitivity analysis that analyzed its components individually instead of whole pathological T3a, neither perinephric fat invasion, sinus fat invasion, nor renal vein invasion was associated with recurrence-free survival.Male sex and clinical T1b were significant predictors for pathological T3a upstaging after partial nephrectomy in clinical T1 renal cell carcinoma patients. Although patients with pathological T3a upstaging had worse recurrence-free survival compared with those without upstaging, multivariable analyses revealed that pathological T3a upstaging was not an independent predictor for poor recurrence-free survival.