Data Processing and Statistical Analysis
We screened data for duplicates, missing information, implausible and outlying values, and insufficient detail. In these cases, we contacted the local hospital representative to provide the requested information. Only completed questionnaires were analyzed. We grouped the participating countries as northern Europe (Denmark and Sweden), eastern Europe (Poland), central Europe (Austria, Belgium, Germany, France, Switzerland, the Netherlands), southern Europe (Italy, Spain) and the UK based on previous publications on European pediatric oncology patients.1
Continuous variables were displayed as medians with interquartile ranges (IQRs). Categorical variables were displayed as frequencies (%). Due to the low numbers, no statistical comparisons were made.