Statistical analysis
Statistical analysis was performed with JMP 12.0.1© Software (SAS institute, Cary NC, USA). Numeric variables are expressed in means with standard error of means (means ± SEM) and categorial data as absolute numbers and percentages. Continuous data were tested using T-Test, categorial variables with the Fisher-exact test. Time-to-event analysis were performed using Kaplan-Meier method and a logrank-test. A p-value <0.05 was considered statistically significant.