1 Swansea Bay University Health Board, South West Wales Cancer Centre, Swansea, UK; The University of Manchester, Manchester, UK. Electronic address: catherine.stanford-edwards@wales.nhs.uk.
2 Swansea Bay University Health Board, South West Wales Cancer Centre, Swansea, UK.
3 Swansea Bay University Health Board, South West Wales Cancer Centre, Swansea, UK; Swansea University Medical School, Swansea, UK.