1. Department of Surgical Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands;
2. Department of Gastroenterology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands;
3. Department of Pathology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands;
4. Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands;
5. Department of Radiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands;
6. Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands;
7. Department of Medical Oncology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands