Survival risk classifiers established by nomograms
REGRESSION
The multivariate Cox regression formulas of the nomograms for OS and CSS formed in training cohort were applied into patients in three cohorts using “nomogramFormula” R package. All patients were divided into high‐ and low‐risk groups according to the total points calculated via “survminer” R package. The Kaplan–Meier (K‐M) method was used to assess the survival difference of OS and CSS between two risk groups.