1. Department of Medical Oncology, Leiden University Medical Center, Leiden, Netherlands
2. Department of Medical Statistics and Bioinformatics, Leiden University Medical Center, Leiden, Netherlands
3. Department of Research, Netherlands Comprehensive Cancer Organisation (IKNL), Utrecht, Netherlands
4. Department of Pathology, Leiden University Medical Center, Leiden, Netherlands
5. Department of Radiotherapy, The Netherlands Cancer Institute, Amsterdam, Netherlands
6. Department of Radiotherapy, Leiden University Medical Center, Leiden, Netherlands