1 Department of Internal and Integrative Medicine, Kliniken Essen-Mitte, Faculty of Medicine, University of Duisburg-Essen, 45276 Essen, Germany.
2 University of Kansas Cancer Center, Kansas City, KS 66160, USA.
3 Institute for Social Medicine, Epidemiology, and Health Economics, Charité Universitätsmedizin Berlin, 10098 Berlin, Germany ; Center for Integrative Medicine, Maryland School of Medicine, University of Maryland, Baltimore, MD 21201, USA.
4 Department of General Oncology and the Integrative Medicine Program, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.