1. Department of Surgery, Leiden University Medical Centre, Leiden, The Netherlands
2. Department of Clinical Oncology, Leiden University Medical Centre, Leiden, The Netherlands
3. Department of Surgery, Leyenburg Hospital, The Hague, The Netherlands
4. Department of Surgical Oncology, Groningen University Hospital, Groningen, The Netherlands
5. Department of Surgery, Catharina Hospital, Eindhoven, The Netherlands