Department I of Internal Medicine, Hematology and Oncology, Intensive Care Medicine, Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf, University of Cologne, Kerpener Strasse 62, 50937, Cologne, Germany. boris.boell@uk-koeln.de. Department of Hematology and Oncology, Otto-von-Guericke University Magdeburg, Medical Center, Magdeburg, Germany. Department of Hematology and Oncology, Mannheim University Hospital, Heidelberg University, Mannheim, Germany. Clinic for Hematology and Oncology, University Medicine Göttingen, Georg-August-University, Göttingen, Germany. Department of Internal Medicine, Frankfurt (Oder) General Hospital, Frankfurt/Oder, Germany. Department of Hematology, Oncology and Palliative Care, Vivantes Clinic Neukoelln, Berlin, Germany. Department I of Internal Medicine, Hematology and Oncology, Intensive Care Medicine, Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf, University of Cologne, Kerpener Strasse 62, 50937, Cologne, Germany. Department of Bone Marrow Transplantation, West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, Essen, Germany. Department of Hematology and Oncology, Campus Fulda, Philipps-University Marburg, Fulda, Germany. Department of Hematology and Oncology, University Hospital Oldenburg, Oldenburg, Germany. Department of Hematology, Oncology, and Tumor Immunology, Charité - Universitätsmedizin Berlin, Berlin, Germany. Department of Hematology and Oncology, Helios Klinikum Aue, Aue, Germany. Department of Internal Medicine, Infectious Diseases, University Hospital Frankfurt, Goethe University Frankfurt, Frankfurt am Main, Germany. Department of Hematology, Oncology and Palliative Care, Department of Internal Medicine, Evangelisches Klinikum Bethel, Bielefeld, Germany. Department III of Internal Medicine, Hematology, Oncology and Hemostaseology, Südharzklinikum, Nordhausen, Germany. Department of Hematology, Oncology & Palliative Care, Klinikum Neuperlach, Munich, Germany. Department of Hematology and Oncology, Red Cross Hospital Munich, Munich, Germany.