1. Department of Medical Oncology, Leiden University Medical Center and Groene Hart Ziekenhuis Gouda, Gouda, the Netherlands
2. Department of Radiation Oncology, Leiden University Medical Center, Leiden, the Netherlands
3. Department of Biomedical Science, Medical Statistical Section, Leiden University Medical Center, Leiden, the Netherlands
4. Department of Surgery, Leiden University Medical Center, Leiden, the Netherlands
5. Department of Gastroenterology and Hepatology, Leiden University Medical Center, Leiden, the Netherlands
6. Department of Radiation Oncology, Leiden University Medical Center and The Netherlands Cancer Institute, Leiden, the Netherlands
7. Department of Medical Oncology, Leiden University Medical Center, Leiden, the Netherlands