Complementary Treatment with Mistletoe Extracts During Chemotherapy: Safety, Neutropenia, Fever, and Quality of Life Assessed in a Randomized Study

Objectives: Evaluate the safety and clinical response of complementary treatment with European mistletoe extracts during chemotherapy.

Design: Monocentric controlled trial with 95 patients randomized into three groups.

Settings/location: National Cancer Research Center of Serbia.

Subjects: Breast cancer patients (stage T_1-3N_0-2M₀) undergoing surgery and adjuvant chemotherapy with six cycles of cyclophosphamide, adriamycin, and 5-fluorouracil.

Interventions: Two different European mistletoe extracts (Helixor A, Iscador M Spez) were injected three times per week during 18 weeks of chemotherapy in the mistletoe group. Five-year follow-up of routine visits was documented in case report forms.

Outcome measures: Safety was assessed by measuring adverse events, body temperature during chemotherapy, and probability of relapse or metastasis in a 5-year follow-up. During chemotherapy, the neutrophil count and quality of life according to EORTC QLQ-C30 were assessed.

Results: The two patient groups receiving different complementary mistletoe treatments were integrated into one mistletoe group for this safety analysis. Patients in the mistletoe group did not develop more fever symptoms than patients in the control group (two short-term events in each group). No significant differences in probability of relapse or metastasis were measured between the groups (p = 0.7637). The mistletoe group showed a trend toward less neutropenia (p = 0.178) and improved pain and appetite loss scores (p < 0.0001 and p = 0.047, respectively) while having positive, but not significant, impact on other EORTC QLQ-C30 scores.

Conclusions: Mistletoe extracts were safe in this clinical study. Neither did subcutaneous injections induce fever, nor did they influence the frequency of relapse and metastasis within 5 years. This result suggests that mistletoe extracts had no adverse interactions with the anticancer agents used in this study. Furthermore, certain side effects of chemotherapy decreased under this complementary treatment in breast cancer patients.