Statistical Analysis
All analyzes were done with IBM SPSS Statistics Version 20.0 statistical software package. Categorical variables were expressed as numbers and percentages, while continuous variables were summarized as mean and standard deviation as well as median and minimum-maximum if necessary. The chi-square test was used to compare categorical variables between the groups. For non-normal distributed data, Kruskal Wallis test was used to compare more than two groups. For univariate analysis event free survival was calculated by Kaplan-Meier method and log rank test was performed. Cox regression analysis was performed to determine significant predictors of OS and CSS variable. In univariate analysis, variables significant at the P <0.1 level were entered in Cox regression analysis. The statistical level of significance for all tests was considered to be 0.05.