2.3 Statistical Analysis
The descriptive analyses were presented as median and mean with standard deviation for numerical data, and frequency and and percent for categorical data. The comparisons between independent groups were performed using Mann-Whitney U and Chi-square for numerical and categorical variables, respectively. The overall survival (OS) and progression-free survival (PFS) were calculated as the time frame from diagnosis to last follow up and/or death for OS, and time frame from treatment initiation to progression and/or death for PFS. The median follow-up was calculated as the time from diagnosis to last follow-up or death date. The survival comparisons were done using the Kaplan-Meier method and the log-rank test. The variables with a p-value <=0.25 were considered as candidate variables for multivariate analyses. SPSS 25 software (IBM Inc., Armonk, NY, USA) was used for the analyses in the study, and a p-value below 0.05 was considered as statistically significant.