1. Surgical Outcomes Research Centre, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.
2. Sydney Local Health District and Sydney School of Public Health, University of Sydney, Sydney, Australia.
3. Department of Colorectal Surgery, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.
4. University of Sydney, Sydney, Australia.
5. Sydney Gynaecological Oncology Group, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.