Development and Validation of a Nomogram for Predicting Postoperative Recurrence-Free Survival in Patients With Nonmetastatic Pathological T3a Stage Renal Cell Carcinoma.

Background: To establish a nomogram predicting postoperative recurrence-free survival (RFS) in patients with nonmetastatic renal cell carcinoma (RCC) of pathological T3a (pT3a) stage undergoing nephrectomy.

Materials And Methods: A retrospective review included 668 patients with pT3a RCC between 2008 and 2019, randomly divided into training and validation groups (7:3 ratio). Cox regression analysis established the RFS-predicting nomogram in the training group. Nomogram performance was assessed using Harrell's concordance index (C-index), time-dependent receiver operating characteristic curve, decision curve analysis, and Kaplan-Meier survival analysis.

Results: Of the 668 patients with pT3a RCC, 167 patients experienced local recurrence or distant metastasis. Using multivariable Cox regression analysis, tumor size, ISUP grade, necrosis, capsular invasion, pT3a invasion pattern were identified as the significant predictors for RFS to establish the nomogram. The C-index of the nomogram was 0.753 (95% CI, 0.710-0.796) and 0.762 (95% CI, 0.701-0.822) for the training and validating group, respectively. The areas under the 1-year, 3-year and 5-year RFS receiver operating characteristic curves were 0.814, 0.769 and 0.768, respectively. Decision curve analysis showed the optimal application of the model in clinical decision-making. Patients with low risk T3a RCC have better RFS than those with high risk T3a RCC.

Conclusion: Tumor size, ISUP grade, necrosis, capsular invasion and T3a invasion patterns were independent risk factors for worse RFS in patients with nonmetastatic pT3a RCC. The current nomogram could effectively predict the RFS of patients with nonmetastatic pT3a RCC.