1 Department of Geriatric Medicine, Diakonessenhuis, 3582 KE Utrecht, the Netherlands.
2 Department of Surgery, University of Groningen, University Medical Center Groningen, 9700 RB Groningen, the Netherlands.
3 University of Groningen, University Medical Center Groningen, Department of General Practice and Elderly Care Medicine, 9700 RB Groningen, the Netherlands.
4 Department of Medical Oncology, Leiden University Medical Center-LUMC, 2333 ZA Leiden, the Netherlands.
5 University of Groningen, University Medical Center Groningen, University Center for Geriatric Medicine, 9700 RB Groningen, the Netherlands.
6 University of Groningen, University Medical Center Groningen, University Center for Geriatric Medicine, 9700 RB Groningen, the Netherlands. Electronic address: s.festen@umcg.nl.