Winston is a practising medical oncologist and clinical pharmacologist, specialising in gastrointestinal cancer. He is currently the Director of the Cancer Services Stream and Chief Medical Information Officer for the South Eastern Sydney Local Health District. His main clinical activity is supporting the St George Hospital Peritoneal Surface Malignancy Unit and he is internationally recognised in this role.
Winston convenes the Basic Sciences of Oncology course though the Cancer Institute of NSW and HETI, and he is a member of the Board of Directors of NPS MedicineWise. Winston has previously been a member of the leadership teams of the Translational Cancer Research Network and UNSW Sphere Cancer CAG. In addition, he has published extensively in areas ranging from basic science through to clinical trials and health services research.