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.