Risk group stratification
Risk group stratification was conducted using the score calculated by the nomogram to divide the entire data set into three risk groups. The high-, medium-, and low-risk groups included individuals whose scores were higher than the score of 30%, between the scores of 30 and 70%, and lower than the score of 70% 1-year PFS probability, respectively. Then the progression-free survival curves of each group were created by K-M estimates to compare the PFS. A simplified scoring system was built to provide a more convenient approach to evaluating the risks without decreasing the prediction accuracy of the original model. Moreover, a typical case was used to show the practicability of this system.