1 Research Institute Havelhöhe (FIH), Havelhöhe Hospital, 14089 Berlin, Germany ; Department of Oncology, Havelhöhe Hospital, 14089 Berlin, Germany ; Institute for Social Medicine, Epidemiology and Institute for Social Medicine, Epidemiology and Health Economics, Charité University Medicine, 14089 Berlin, Germany ; Institute of Integrative Medicine, University of Witten/Herdecke, 58313 Herdecke, Germany.
2 Institute for Applied Epistemology and Medical Methodology, University of Witten/Herdecke, 79111 Freiburg, Germany.
3 Academic Unit of Primary Health Care, School of Social and Community Medicine, Bristol BS8 2PS, UK.
4 INSERM U1138, Université Paris Descartes, 75006 Paris, France.
5 College of Medicine, Drexel University, Philadelphia, PA 19129, USA.