Statistical analysis

Descriptive statistics were presented using the median and interquartile range, and categorical variables were presented using frequency and percent. AGR was calculated as follows:

Comparisons between independent groups were performed with the Mann-Whitney U test and chi-squared test, respectively. The cut-off value for AGR was determined with the receiver operating characteristic (ROC) analysis using Youden’s J index. OS was calculated as the time frame from the initiation of the 1^st line treatment to the last follow-up and/or death, and the progression-free survival was calculated as the duration from the initiation to the end of the 1^st line treatment and/or death. The survival analyses were done using the Kaplan-Meier method, and the comparisons between prognostic sub-groups were done with the log-rank test. The multivariate analyses of survival were done using Cox regression method. All analyses were significant at the p<0.05 level, and Statistical Package for Social Sciences, version 25, (IBM SPSS Corp., Armonk, NY, USA) software was used for the statistical analyses in the study.