L T Tan1, K Tanderup2, P Hoskin3, R Cooper4, R Pötter5. 1. Cambridge University Hospitals NHS Trust, Cambridge, UK. Electronic address: litee.tan@addenbrookes.nhs.uk. 2. Aarhus University Hospital, Aarhus, Denmark. 3. Mount Vernon Cancer Centre, Northwood, UK. 4. Leeds University Hospital NHS Trust, Leeds, UK. 5. Medical University of Vienna, Vienna, Austria.