The Mistletoe and Breast Cancer (MAB) Study: a UK Pilot Mixed Method, Placebo-Controlled Randomised Trial

Background/Objective: To test the feasibility of a pilot, randomised controlled trial of mistletoe therapy (MT) with an embedded qualitative study in the UK National Health Service (NHS) setting. Methods: 45 patients were recruited via an NHS oncology centre with a diagnosis of early or locally advanced breast cancer. Participants were allocated to: Iscador® Malus, Iscador® Pinus or physiological saline (placebo). Diaries and Quality of life questionnaires were administered. Qualitative interviews were con-ducted with participants, oncologists, and nurses. Feasibility was assessed by recruitment, retention, adherence, blinding and safety. Results: Sixty-seven patients approached August 2019-March 2020, and 15 gave consent. 14 participants were randomised, two withdrew during the trial. Ten participants and five staff were interviewed. Barriers to recruitment were the additional treatments/time, extra injections, and the possibility of placebo allocation. Adherence was very good. Diaries and interviews indicated that some participants struggled with injections and skin reactions. Participants perceived MT as natural, immune-boosting and promoting self-healing. There were 22 adverse events due to the MT, related to the injections or skin reactions. Conclusion: It is feasible in the UK to recruit breast cancer patients into a randomised controlled trial of MT versus placebo, for them to adhere, and provide follow-up data.