Mistletoe extract (Iscador®) in cancer patients undergoing chemotherapy for prostate and bladder tumors: A prospective observational study

Objective: While mistletoe (a semi-parasitic evergreen plant) extract is commonly used as a complementary therapy in Europe, the evidence for its efficacy against the toxicity of chemotherapy is mixed. Our study aimed to evaluate the impact of mistletoe extract as a complementary therapy on the health-related quality of life (HRQoL) and hematological toxicities in patients with metastatic prostate and bladder cancers undergoing chemotherapy. Materials and Methods: This observational study prospectively involved patients with metastatic prostate and bladder cancers treated with either chemotherapy alone or in combination with Iscador®, a mistletoe extract. The study's primary outcome was HRQoL assessed at baseline and after each chemotherapy cycle. Secondary outcomes included hematological toxicities.Results: A total of ۱۱۶ patients, including ۵۹ with prostate cancer and ۵۷ with bladder cancer, were enrolled. Analysis of the HRQoL symptom scales of prostate cancer patients revealed significant improvement in fatigue (p=۰.۰۱۴), pain (p=۰.۰۲۳), insomnia (p=۰.۰۱۷), and diarrhea (p=۰.۰۳۱) in the mistletoe extract group compared to the control group. In bladder cancer patients, no significant differences were observed in the HRQoL scales between the two treatment groups. Moreover, no significant differences were found between the mistletoe extract and control groups regarding hematological toxicities.Conclusion: Our study showed that mistletoe extract significantly improved four scales of HRQoL in prostate cancer patients undergoing chemotherapy. However, in patients with bladder cancer, the addition of mistletoe extract to chemotherapy does not appear to have a substantial impact on HRQoL, and thus, it should not be considered a complementary therapy for these patients.