• Effect of mistletoe extract on tumour response in neoadjuvant chemoradiotherapy for rectal cancer: a cohort study
• Efficacy and safety of postoperative mistletoe therapy in patients with primary non-metastatic colorectal cancer – a multicentre, comparative, epidemiological cohort study

Last update: June 13th, 2023/AT1

Baek et al. 2021 [318]

Patients and methods

This retrospective observational study included 52 patients with clinically confirmed stage II-III adenocarcinoma of the rectum treated with long-term neoadjuvant chemoradiotherapy (NCRT) at a reference hospital in Korea between January 2018 and July 2020.

Results

Of the 52 patients, 37 were treated with NCRT alone and 15 patients also received the mistletoe extract abnobaVISCUM quercus, which was administered subcutaneously three times a week in an increasing dose of 0.02 mg at the beginning up to a maximum of 20 mg. The median age of the patients was 68 years and the study group included 35 men and 17 women. In the group with additional mistletoe therapy, a significantly higher rate of complete remissions (53.3% vs. 21.6%, p = 0.044) and a significantly higher downstaging (86.7% vs. 56.8%, p = 0.040) was observed compared to the group with NCTR alone. (86.7% vs. 56.8%, p = 0.040) was observed compared to the group with NCTR alone.

Conclusion

NCRT in combination with mistletoe extract resulted in a better tumour response than conventional chemoradiotherapy alone in patients with rectal cancer. However, further prospective randomised trials are needed to confirm efficacy.

Last update: June 13th, 2023/AT1

Friedel et al. 2009, Zänker et al. 2012, Bock et al. 2014 [42, 103, 104]

These are three publications of a study which has been published under different aspects in several scientific journals.

Patients and methods 

In this multicentre, controlled, retrospective, epidemiological cohort study conducted according to the guidelines of good epidemiological practice (GEP), the efficacy of mistletoe therapy was evaluated. The study included 804 patients with primary, non-metastatic colorectal cancer of UICC stages I to III from various centres in Germany and Switzerland. The study evaluated the frequency of side effects caused by chemo-/radiotherapy as well as the persistence of disease- and treatment-related symptoms in the mistletoe therapy group compared to the control group. The Karnofsky Index, the duration of hospitalisation during the observation period and tumour-free survival (DFS) were also recorded. 

429 patients received the mistletoe extract Iscador M or Qu s.c. as part of a supportive long-term therapy after surgery two to three times a week in addition to conventional chemo- and/or radiotherapy or in oncological aftercare. 

The per-protocol analysis from the verum group also included a subgroup of 106 patients who received an oak mistletoe extract. The 375 patients in the control group were treated only with conventional therapies or received only aftercare without further medication.

The median observation period was 58 months in the mistletoe therapy group and 51 months in the control group. The median duration of mistletoe therapy was 53 months. 

In a second analysis, patients who had developed a tumour-related fatigue syndrome at the beginning of the study were selected from the study group. A total of 143 patients without mistletoe therapy and 181 with additive mistletoe therapy were included. 

Results

The patients in the mistletoe therapy group showed significantly fewer side effects caused by chemo- and/or radiotherapy than the control group: only about 19 per cent of the patients that received additional mistletoe therapy developed these side effects compared to almost 50 per cent of the patients in the control group. 
The subgroup analysis of 106 patients showed an even greater difference. Only 7.5 per cent of the group with the Iscador Qu preparation developed these side effects caused by chemo-/radiotherapy compared to almost 50 per cent of the control group.

Patients with additional mistletoe therapy also developed fewer disease- and therapy-related symptoms such as nausea or vomiting, loss of appetite, depression, fatigue, irritability or exhaustion, sleep disorders, mucositis or skin reactions. The Karnofsky Index also improved significantly in the mistletoe therapy group (p < 0.001). The performance of the patients in the mistletoe group increased continuously and significantly to 86.8 per cent during the first chemotherapy cycle and even rose up to 93.7 per cent after chemotherapy. In contrast, the control group showed a slight decrease in clinical performance after the first therapy cycle, which then nearly reached the original value of 84.6 percent after the therapy.

The average duration of hospitalisation was also significantly shorter (p = 0.015) with 35.5 days in the mistletoe therapy group than in the control group, which stayed in hospital for an average of 41.2 days.

In addition, an advantage in tumour-free survival (DFS) was observed. Thus, the adjusted relative hazard ratio (HR) for DFS in the mistletoe therapy group was 0.68 (0.51-0.92, p = 0.013), which corresponds to a significant reduction of the estimated relative risk by approximately 32% and a reduction in the recurrence rate by approximately one third.

In order to assess therapeutic safety, the adverse drug reactions caused by mistletoe therapy were evaluated. Ten patients (2.3%) reacted with systemic side effects such as dizziness, fatigue, depression, tinnitus, nausea, mild fever or itching. All side effects were mild to moderate (WHO/CTC grade 1-2). Due to these side effects, five patients aborted the therapy prematurely. One patient showed an acute allergic reaction. 

In 100 patients (23.3%) local reactions such as indurations, erythema, itching or oedema around the injection site occurred, which were always mild to moderate and subsided completely. There were no life-threatening side effects.

Of the 143 patients who received no mistletoe therapy, 86 still suffered from tumour-related fatigue syndrome by the end of observation. In contrast, only 16 of the 181 patients who received mistletoe therapy showed these symptoms by the end of observation. 

Conclusion

These study results demonstrate that mistletoe therapy, in addition to conventional oncological basic treatment, can significantly reduce the side effects caused by these therapies and may contribute to prolonging survival. Furthermore, mistletoe therapy is a suitable intervention to reduce the tumour-related fatigue syndrome.

Last update: January 4th, 2021/AT