Figure 4. Patients’ age as an independent prognostic factor. Associations of clinical variables and primary treatment with OS were analyzed using multivariate analysis. Forest plots indicate the independent prognostic effects of patients’ age, as a continuous variable, and other clinical variables on OS. HRs were derived from multivariate Cox regression models, with 95% CIs and P-values for OS. OS, overall survival; HR, hazard ratio; CI, confidence interval.