Additional treatment with mistletoe extracts for patients with breast cancer compared to conventional cancer therapy alone - efficacy and safety, costs and cost-effectiveness, patients and social aspects, and ethical assessment.

Background: Chemotherapy is often used in the treatment of breast cancer in women. Side effects such as diarrhea, fatigue, hair loss, fever or disturbances in blood formation impair the women's quality of life. An essential treatment goal of the accompanying mistletoe therapy (MT) used in complementary medicine is to improve the health-related quality of life during cancer therapy. Aim and methods: The HTA report on which this article is based examines the medical efficacy and safety, costs and cost-effectiveness, patient and social aspects, and ethical aspects of MT in women with breast cancer. Systematic reviews were conducted for this purpose. The search period of the literature search ranged from 2004 to October 2020. Results: A total of 2 evidence-based medical guidelines, 3 randomized trials assessing efficacy and 1 additional non-randomized intervention trial, as well as 3 observational studies assessing safety, a cost analysis, 12 cross-sectional studies on patient aspects and 17 articles on ethical evaluation were included. Improvements in health-related quality of life compared to the control group were small to moderate. Due to the high risk of bias in the studies, it is possible that the difference is not caused by MT. One study with a small sample size showed no effect on progression-free survival after 5 years. Studies on the effect of MT on overall survival are lacking. In seven studies, local skin reactions of low and moderate severity were reported in a median of 25% (range 5 to 94%) of patients, and mild to moderate systemic reactions in a median of 2% (range 0 to 8%) of patients. A comparative cost analysis from Germany reported significantly lower medical costs within 5 years after surgery for patients with MT than for patients without MT, but the underlying observational study did not control for systematic bias. With regard to patient aspects, the frequency of use and the reasons for use from the patient's or practitioner's point of view were mainly investigated. A median of 25% (range 7 to 46%) of patients with breast cancer and 29% (range 29 to 79%) of treatment providers use MT. The main motivations of patients for use were to reduce side effects, strengthen the immune system and take an active role in the treatment process. Patients felt insufficiently advised. Studies on other aspects are lacking. The ethical evaluation was able to identify 6 overarching themes; the central challenge is the insufficient evidence on efficacy and safety.