Statistical analysis
REGRESSION
The final included UCCC patients were randomly assigned to the training set and the validation set in a 7:3 ratio using R software. The training set was used to build a risk prediction model and to construct a nomogram to predict a patient's CSS at 5 and 10 years. Validation groups are used for internal validation. For comparison of count data between groups, chi-square or Fisher's exact test is used; for comparison of multi-category variables between groups, chi-square test or Fisher's exact probability method for R*C tables is used. Continuous variables were compared using the t-test or the Mann–Whitney U test. In the training group, univariate and multivariate analyses were performed by Cox proportional hazards regression models to identify independent prognostic factors associated with CSS. The patient characteristics with 