Prognostic value of preoperative carcinoembryonic antigen/tumor size in rectal cancer

Figure 5 Proportional hazards assumption test for overall survival by plotting the Schoenfeld residuals against time in the training cohort (A, C, E, and G) and the validation cohort (B, D, F, and H). The X-axis represents the survival time, while the Beta values referring to age, TNM stage, differentiation, and carcinoembryonic antigen/tumor size are shown on the Y-axis. The constant mean of residuals across time confirms that the proportional hazard assumption holds for these covariate with all of the P-values > 0.05. CEA: Carcinoembryonic antigen.