Dr Mary Lei is a highly esteemed consultant clinical oncologist at Guy's and St Thomas' NHS Foundation Trust, specialising in the treatment of head, neck, and thyroid tumours. She has been serving in this role since 2011, bringing a wealth of expertise and dedication to her patients and the medical community.

Dr Lei completed her undergraduate medical training at King's College London School of Medicine and Dentistry. She then pursued specialist training in clinical oncology at Imperial College Healthcare and Guy's and St Thomas' NHS Foundation Trusts. Her commitment to advancing medical knowledge led her to spend two years as a research fellow at the Royal Surrey County Hospital and the University of Surrey. During this time, her research on image-guided intensity-modulated radiotherapy (IMRT) in head and neck cancer earned her a Medical Doctorate (MD) postgraduate degree.

Following her research fellowship, Dr Lei was appointed to a one-year charity-funded IMRT fellowship in head and neck cancer at Guy's and St Thomas' NHS Foundation Trust. Her dedication to the field of oncology is further demonstrated by her role as Chair of the Oncology Trainee Forum, where she represented clinical oncology trainees across the UK at the Royal College of Radiologists. She continues to contribute to the development of clinical oncology training and serves as both an educational and clinical supervisor.

In her current role, Dr Lei leads the clinical oncology radiotherapy research and development (R&D) group and oversees research and development for the network thyroid cancer team. Her research interests are focused on novel therapies and predictive biomarkers in head and neck cancer, and she collaborates with colleagues at King's Health Partners to advance this work.

Dr Lei's areas of expertise include radiotherapy, with a particular focus on head, neck, thyroid, and neuroendocrine tumours. Her dedication to patient care and research makes her a leading figure in the field of clinical oncology.