Construction and validation of the nomogram
micropapillary bladder cancer, Micropapillary bladder cancer
REGRESSION
Eligible micropapillary bladder cancer patients from the SEER database were randomly divided into a training set and an internal validation set using a ratio of 7:3. Micropapillary bladder cancer patients from the tertiary center were designated as the external validation set. External validation was performed to further verify the accuracy of the nomograms.Univariate and multivariate Cox regression analyses were performed on patients in the training set to evaluate the variable’s impact on CSS and OS, presenting as a hazard ratio (HR) and corresponding 95% confidence interval (CI). Based on results of the multivariate Cox regression analysis, nomograms were created for predicting the probability of 1-, 3-, and 5-year CSS and OS. The internal validation of the nomogram was performed in the internal validation set and the external validation was conducted using external validation set. Validation of this nomogram was then performed using bootstrapping with 1000 resamples. The accuracy of nomograms was evaluated using a calibration curve through comparing nomogram-predicted survival with actual survival. The discriminatory ability of the nomogram was evaluated by the concordance index (C-index) and the receiver operating characteristic (ROC) curves with the calculated area under the curve (AUC). In addition, decision curve analysis (DCA) was applied to estimate the clinical net benefit of the nomogram by comparing the threshold probabilities range of the model to that of the AJCC staging system.All statistical analyses were conducted by R version 4.2.0 (