Statistical analysis
All data were summarized using standard descriptive statistics. Event-free (EFS) and overall survival (OS) estimates were obtained using the Kaplan-Meier method and presented with corresponding 95% confidence intervals. EFS was defined as the time elapsed from diagnosis to the date of first progression, death, or censoring. OS was defined as the time elapsed from diagnosis to death or censoring. Cox proportional hazard models were used to assess the effect of demographic and clinical variables on survival. Model estimates were presented as hazard ratios and corresponding 95% confidence intervals. All p-values were two-sided and those <0.05 were considered statistically significant. Statistical analyses were performed using R statistical software (R Foundation for Statistical Computing, Vienna, Austria) with the survival and survminer packages.