1. Cancer and Palliative Care Research and Evaluation Unit, School of Surgery, University of Western Australia (UWA), Crawley, WA, Australia
2. Department of Respiratory, Sir Charles Gairdner Hospital, Nedlands WA, Australia
3. Centre for Applied Statistics, University of Western Australia (UWA), Crawley, WA, Australia
4. School of Population and Public Health, University of Western Australia (UWA), Crawley, WA, Australia