1. Department of Surgery & Medical Oncology, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Str. 22, D-81675 Munich, Germany.
2. Department of Gastroenterology, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Str. 22, D-81675 Munich, Germany.
3. Department of Surgery, Paracelsus Medical University (PMU) Salzburg, Salzburger Landeskliniken, Müllner Hauptstraße 48, A-5020 Salzburg, Austria.