1. Cochrane Haematology, Department I of Internal Medicine, Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf; Faculty of Medicine and University Hospital Cologne, University of Cologne; Cologne Germany
2. Institute of Medical Statistics and Computational Biology; Faculty of Medicine and University Hospital Cologne, University of Cologne; Cologne Germany
3. Institute of Health Economics and Clinical Epidemiology; University of Cologne, Faculty of Medicine and University Hospital Cologne; Cologne Germany
4. Department of Medicine V; University of Heidelberg; Heidelberg Germany
5. Cochrane Cancer, Department I of Internal Medicine, Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf; Faculty of Medicine and University Hospital Cologne, University of Cologne; Cologne Germany