Tumorwachstumsstimulation durch Mistelpräparate? Fakten und Artefakte

The potential of a tumour stimulation by low doses of mistletoe extract has been controversially discussed in the medical community since the early 90ies. Safety doubts were mainly based on the following hypothesis: Mistletoe extracts as well as mistletoe lectins are able to induce the release of pro-inflammatory cytokines (e.g. IL-6) which could stimulate the growth of certain malignant cells. Additionally, results of a limited series of IN VITRO experiments and animal studies, one case report regarding a patient suffering from a centrocytic non-Hodgkin's lymphoma as well as the results of a prospective, randomized, multicenter EORTC study on high-risk stage II and III melanoma patients seem to support this hypothesis. However, the results of the IN VITRO experiments could not be reproduced in recent substantial investigations and are suggested to be statistical artefacts. The animal studies did not show any drug safety risks for mistletoe by thorough analysis. The EORTC melanoma study did not reveal any statistically significant differences in disease-free and overall survival between the mistletoe group, the interferon groups and the untreated control group. Complementary therapy with standardized mistletoe extracts is considered to be safe and harmless.