1. Department of Neurosurgery, Oslo University Hospital, Ulleval, Oslo, Norway;
2. Neurosurgery Unit, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia;
3. Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway;
4. Oslo Centre for Biostatistics and Epidemiology, Research Support Services, Oslo University Hospital, Oslo, Norway;
5. Department of Gynecologic Oncology, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway;
6. The Cancer Registry of Norway, Oslo, Norway;
7. Department of Public Health, Norwegian University of Science and Technology, Trondheim, Norway;
8. FORMI and Department of Neurology, Oslo University Hospital, Ulleval, Oslo, Norway