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.