In the early 1970s, Dr. M. Vera Peters, radiation oncologist at Toronto's Princess Margaret Hospital, discovered that women with early breast cancer could be cured with lumpectomy (removal of the tumour alone) rather than the standard mutilating radical mastectomy. She embarked on a quest to change surgical practice, but her ideas met with skepticism and hostility from the medical establishment. It was not until the end of her career that randomized trials confirmed her results and surgicial practice started to change. This presentation describes Peters' career and the development of a play, Radical, about her work in breast cancer. It also discusses the role of drama in illuminating medical history and practice, and the challenges and pitfalls involved in bringing medical history to the stage.