[1] Vrije Universiteit Brussel,Department of Medical Oncology, Oncologisch Centrum, UZ Brussel
[2] University Hospitals Leuven,Department of General Medical Oncology
[3] University Hospitals Leuven,Department of Geriatric Medicine
[4] University Hospitals Leuven,Department of Respiratory Oncology
[5] Vrije Universiteit Brussel,Department of Geriatric Medicine, UZ Brussel
[6] KU Leuven,Department of Clinical and Experimental Medicine
[7] Consultant in Statistics,Department of Public Health and Primary Care, Academic Centre for Nursing and Midwifery
[8] KU Leuven,Department of Oncology
[9] KU Leuven,undefined