He is the cancer lead for the Royal Liverpool University Hospital Trust and the medical director of the Merseyside and Cheshire Cancer Network. He runs a large portfolio of breast cancer trials and is a member of the National Cancer Research Institute (NCRI) breast clinical trials group. Dr Holcombe is an honorary senior lecturer at the University of Liverpool and has also published extensively on the psychological impact of breast cancer diagnosis and treatment. He has a wider interest in the organisation and delivery of cancer services and has also trained widely in general surgery. He completed his MD thesis while working as a surgeon in West Africa.