1. From the Departments of Medical Oncology and Hematology and Surgery, Kliniken Essen-Mitte; Institute for Medical Informatics, Biometry and Epidemiology, Department of Radiation Oncology, and Department of Internal Medicine (Cancer Research), West German Cancer Center, University of Essen Medical School, Essen; Department of Surgery, Klinikum Solingen, Solingen; Departments of Gastorenterology, Radiation Oncology, and Surgery, University Clinic, Tübingen; and Departments of Gastroenterology, Radiation...