1. Department of General Surgery, Sandwell and West Birmingham Hospitals NHS Trust, Birmingham, West Midlands, UK
2. Cancer and Genomic Science, College of Medical and Dental Science, University of Birmingham, Edgbaston, Birmingham, UK
3. Department of General Surgery, Dudley Group of Hospitals NHS Trust, Russells Hall Hospital, Dudley, West Midlands, UK
4. School of Medicine, University of Birmingham, Birmingham, West Midlands, UK
5. Department of General Surgery, Walsall Healthcare NHS Trust, Manor Hospital, Walsall, West Midlands, UK