1. Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands
2. Department of Radiotherapy, Netherlands Cancer Institute—Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands
3. Department of Surgery, Netherlands Cancer Institute—Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands
4. Department of Comprehensive Cancer Centre South, Eindhoven, The Netherlands
5. Department of Medical Statistics, Leiden University Medical Center, Leiden, The Netherlands
6. Department of Comprehensive Cancer Centre Leiden, The Netherlands
7. Department of Gastroenterology and Hepatology, Netherlands Cancer Institute—Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands