Prospective controlled cohort studies on long-term therapy of cervical cancer patients with a mistletoe preparation (Iscador)

Systematic assessment of the influence of quality of studies on mistletoe in cancer care on the results of a meta-analysis on overall survival

PURPOSE

Mistletoe treatment in cancer patients is controversial, and a Cochrane review concluded that due to heterogeneity, performing a meta-analysis was not suitable. However, several systematic reviews included meta-analyses in favor of mistletoe. The aim of this work was to assess the influence of the methodological quality of controlled studies on the results of a meta-analysis regarding overall survival.

METHODS

Between April and August 2022, Medline, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), PsycINFO, CINAHL and Web of Science were systematically searched. In addition, reference lists of previously published meta-analyses were checked for relevant publications. A random effects meta-analysis with clustering was performed. The risk of bias within the studies was assessed using ROB 2.0 and ROBINS-I.

RESULTS

The search identified 4685 hits, and 28 publications reporting on 28 298 patients were included in the quantitative analysis. Overall, the analysis led to a significant result in favor of mistletoe therapy (overall HR = 0.61 with 95% CI [0.53;0.7]). According to our subgroup analysis of randomized studies, studies of higher quality (lower risk of bias) did not lead to a significant result in favor of mistletoe therapy (HR = 0.78; CI = [0.30; 2.00]).

CONCLUSIONS

In the case of mistletoe therapy, the results of the meta-analysis strongly depended on the methodological quality of the included studies. Calculating meta-analyses that include low-quality studies may lead to severe misinterpretation of the data.

Viscum album, as alternative and bridge to palliative chemotherapy in recurrent gallbladder cancer following laparoscopic radical cholecystectomy: a case report

A 78-year-old female patient was initially treated with laparoscopic radical cholecystectomy for gallbladder cancer (pT2aN1M0, stage IIIB). The patient then received adjuvant chemotherapy with gemcitabine. After completion of adjuvant chemotherapy, multiple lymph node metastases were observed in follow-up computed tomography (CT) scan, but the patient refused to go through further chemotherapy. One year after the recurrence, carbohydrate antigen 19-9 (CA19-9) level was 1,925 U/mL with follow-up high-resolution CT/abdomen-pelvic CT showing the increased size of multiple lymph node metastases, and the patient began to undergo Viscum album therapy (0.2 mg, subcutaneously, three times a week). After the V. album therapy was initiated, a decrease in the size of metastatic lymph nodes and CA19-9 level, which was decreased to 252 U/mL, was observed. Seventeen months after continuous V. album therapy, the patient agreed to have palliative chemotherapy. The patient underwent gemcitabine plus cisplatin chemotherapy and showed stable disease during follow-up. This case report suggests that V. album therapy showed anticancer effects and may act as a bridge to palliative chemotherapy for patients with inappropriate general conditions to undergo chemotherapy for recurrent gallbladder cancer.

Phytotherapy in Integrative Oncology-An Update of Promising Treatment Options

Modern phytotherapy is part of today's conventional evidence-based medicine and the use of phytopharmaceuticals in integrative oncology is becoming increasingly popular. Approximately 40% of users of such phytopharmaceuticals are tumour patients. The present review provides an overview of the most important plants and nature-based compounds used in integrative oncology and illustrates their pharmacological potential in preclinical and clinical settings. A selection of promising anti-tumour plants and ingredients was made on the basis of scientific evidence and therapeutic practical relevance and included Boswellia, gingko, ginseng, ginger, and curcumin. In addition to these nominees, there is a large number of other interesting plants and plant ingredients that can be considered for the treatment of cancer diseases or for the treatment of tumour or tumour therapy-associated symptoms. Side effects and interactions are included in the discussion. However, with the regular and intended use of phytopharmaceuticals, the occurrence of adverse side effects is rather rare. Overall, the use of defined phytopharmaceuticals is recommended in the context of a rational integrative oncology approach.

Quality of life in cancer patients treated with mistletoe: a systematic review and meta-analysis

BACKGROUND

Mistletoe extracts are used as an adjunct therapy for cancer patients, but there is dissent as to whether this therapy has a positive impact on quality of life (QoL).

METHODS

We conducted a systematic review searching in several databases (Medline, Embase, CENTRAL, CINAHL, PsycInfo, Science Citation Index, clinicaltrials.gov, opengrey.org ) by combining terms that cover the fields of "neoplasm", "quality of life" and "mistletoe". We included prospective controlled trials that compared mistletoe extracts with a control in cancer patients and reported QoL or related dimensions. The quality of the studies was assessed with the Cochrane Risk of Bias tool version 2. We conducted a quantitative meta-analysis.

RESULTS

We included 26 publications with 30 data sets. The studies were heterogeneous. The pooled standardized mean difference (random effects model) for global QoL after treatment with mistletoe extracts vs. control was d = 0.61 (95% CI 0.41-0.81, p < 0,00001). The effect was stronger for younger patients, with longer treatment, in studies with lower risk of bias, in randomized and blinded studies. Sensitivity analyses support the validity of the finding. 50% of the QoL subdomains (e.g. pain, nausea) show a significant improvement after mistletoe treatment. Most studies have a high risk of bias or at least raise some concern.

CONCLUSION

Mistletoe extracts produce a significant, medium-sized effect on QoL in cancer. Risk of bias in the analyzed studies is likely due to the specific type of treatment, which is difficult to blind; yet this risk is unlikely to affect the outcome.

PROSPERO REGISTRATION

CRD42019137704 .

Statement to an Insufficient Systematic Review on Viscum album L. Therapy

BACKGROUND

Up to 88% of oncological patients apply complementary therapies and up to 77% apply complementary mistletoe therapy in the context of integrative oncological approaches. An evidence-based consultation of oncological health professionals regarding complementary therapies used in Germany is missing. Therefore, a new S3-Guideline for Complementary Medicine in the Treatment of Oncological Patients is under development and is anticipated to be finalized in November 2020. It will be based on evidence-based publications and systematic reviews on complementary therapies in oncology. A recently published two-part systematic review on mistletoe treatment in oncology has been reevaluated.

METHODS

The latest published systematic two-part review on mistletoe has been systematically proofread and checked in compliance with the Cochrane Handbook for Systematic Reviews of Intervention and the AMSTAR 2 (A MeaSurement Tool to Assess Systematic Reviews) tool.

RESULTS

The here discussed two-part review is incomplete, lacks sound accuracy including insufficient assessment of the risk of bias, and contains imprecise statements. In addition, it does not sufficiently comply with the Cochrane Handbook for Systematic Reviews of Intervention and the AMSTAR 2 tool.

CONCLUSION

In view of the approaching release of a new guideline in the field of complementary therapies in oncology, the present statement draws attention to a lack of profound methodology of conductance of a recently released systematic review on mistletoe. In consequence, a comprehensive overview of published mistletoe studies, i.e., a meta-analysis with a sound methodology of conductance, is necessary.

Personality and fatal diseases: Revisiting a scientific scandal

During the 1980s and 1990s, Hans J Eysenck conducted a programme of research into the causes, prevention and treatment of fatal diseases in collaboration with one of his protégés, Ronald Grossarth-Maticek. This led to what must be the most astonishing series of findings ever published in the peer-reviewed scientific literature with effect sizes that have never otherwise been encounterered in biomedical research. This article outlines just some of these reported findings and signposts readers to extremely serious scientific and ethical criticisms that were published almost three decades ago. Confidential internal documents that have become available as a result of litigation against tobacco companies provide additional insights into this work. It is suggested that this research programme has led to one of the worst scientific scandals of all time. A call is made for a long overdue formal inquiry.

Mistletoe in oncological treatment: a systematic review : Part 1: survival and safety

PURPOSE

Mistletoe treatment of cancer patients is discussed highly controversial in the scientific literature. Aim of this systematic review is to give an extensive overview about current state of research concerning mistletoe therapy of oncologic patients regarding survival, quality of life and safety.

METHODS

In September and October 2017 Medline, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), PsycINFO, CINAHL and "Science Citation Index Expanded" (Web of Science) were systematically searched.

RESULTS

The search strategy identified 3647 hits and 28 publications with 2639 patients were finally included in this review. Mistletoe was used in bladder cancer, breast cancer, other gynecological cancers (cervical cancer, corpus uteri cancer, and ovarian cancer), colorectal cancer, other gastrointestinal cancer (gastric cancer and pancreatic cancer), glioma, head and neck cancer, lung cancer, melanoma and osteosarcoma. In nearly all studies, mistletoe was added to a conventional therapy. Patient relevant endpoints were overall survival (14 studies, n = 1054), progression- or disease-free survival or tumor response (10 studies, n = 1091). Most studies did not show any effect of mistletoe on survival. Especially high quality studies do not show any benefit.

CONCLUSIONS

With respect to survival, a thorough review of the literature does not provide any indication to prescribe mistletoe to patients with cancer.

[Malignant head and neck melanoma: Part 2: Therapy]

Resection margins of melanomas in the head and neck region often have to be adapted according anatomical circumstances. In the case of thicker primary tumors or after complete resection of locoregional lymph node metastases, adjuvant therapy with interferon-α can be performed; in some cases, adjuvant radiotherapy may also be indicated. In the case of inoperable lymph node or distant metastases, systemic treatment is required. Beside well-established mono- or polychemotherapy regimens, newer targeted therapies with BRAF inhibitors (vemurafenib, dabrafenib), mitogenic-activated protein kinase (MEK) inhibitors (trametinib, binimetinib, and cobimetinib), and kinase inhibitors (imatinib, sunitinib, nilotinib, dasatinib) are also available.

Bridging cross-cultural gaps: monitoring herbal use during chemotherapy in patients referred to integrative medicine consultation in Israel

INTRODUCTION

The high prevalence of the use of traditional herbs among patients with cancer is a cause for concern with regard to potentially adverse interactions with conventional oncology treatments. In this study, we explore herbal use among patients with cancer in northern Israel who are referred by their health care providers to complementary and traditional medicine (CTM) consultations provided to them within the conventional oncology department. The study's objectives were to identify which herbs patients use and to examine the scope of current research on the efficacy and safety regarding the identified herbs.

PATIENTS AND METHODS

Herbal use by patients receiving oncology care was assessed prospectively from July 2009 to July 2012 by integrative physicians (IPs) trained in herbal medicine. Historical, ethnobotanical, basic research, and clinical data regarding the identified herbs were explored by using a keyword search in PubMed and Middle Eastern ethnohistorical literature.

RESULTS

Disclosure of herbal use was reported by 154 of the 305 patients (50.5 %) interviewed by IPs. The use of 85 single herbs and 30 different herbal formulas was documented during the initial or follow-up IP assessments. Patients reported 14 quality of life-associated indications for herbal use. The ten most prevalent herbs displaying in vitro/in vivo anticancer activity and nine other herbs were preliminarily assessed concerning potential risks, safety, and interaction with chemotherapy.

CONCLUSIONS

Herbal use by patients with cancer in northern Israel is widespread and calls for further study in order to address issues of safety and effectiveness. We recommend constructing a multinational and multidisciplinary team of researchers with ethnopharmacological and clinical expertise that will explore the use of herbs among patients with cancer in a cross-cultural perspective attuned with patients' affinity to traditional herbal medicine.

Attitudes of patients with gynecological and breast cancer toward integration of complementary medicine in cancer care

OBJECTIVE

The purpose of this study was to explore prospectively the perspectives of patients with breast and gynecological cancers regarding integration of complementary and alternative medicine (CAM) in conventional oncology settings.

METHODS

We developed a 27-item questionnaire that was administered to convenient sample of patients with breast cancer and another with gynecological cancer who were attending a community-based oncology service in northern Israel.

RESULTS

Of the 275 respondents, 109 (39.6%) had gynecological cancers and 166 (60.4%) had breast cancer. Current and/or previous year CAM use for oncology treatment was significantly higher among the patients with gynecological cancer (73/166 [44%] vs 67/106 [63%], P = 0.03). A logistic regression model indicated that CAM use was associated with gynecological cancer (EXP [B], 2.51; 95% confidence interval for EXP [B], 1.29-4.88; P = 0.007], younger age, Jewish religion, and lesser degree of religiosity. The patients highly expected their gynecologist-oncologist and family doctor to refer them to CAM counseling. Moreover, they expected their gynecologist-oncologist to participate in building a CAM treatment plan if CAM were to be integrated into the oncology service. The patients expected the CAM consultant to inform them of the safety and efficacy of CAM treatments, emphasizing expectations to strengthen their general ability to cope with the disease, reduce chemotherapy side effects, and provide emotional and spiritual support.

CONCLUSION

Although patients with gynecological malignancies use CAM significantly more than patients with breast cancer, both groups share similar conceptions regarding the active role of their gynecologist oncologists in the process of CAM integration within supportive care and expect CAM consultation to focus on improving their well-being.

Quality of life and related dimensions in cancer patients treated with mistletoe extract (iscador): a meta-analysis

Objectives. The aim of this meta-analysis was to determine the effectiveness of the fermented plant extract Iscador, produced from the white-berry European mistletoe, in the treatment of patients with cancer with respect to quality-of-life- (QoL-) associated measures. Methods. We searched databases such as PubMed/Medline, Excerpta Medica Database (EMBASE), CAMbase, and other for controlled clinical studies on parameters associated with QoL. Outcome data were extracted and converted into standardized mean differences and their standard errors. Results. Thirteen prospective and controlled studies which met the inclusion/exclusion criteria reported positive effects in favor of the Iscador application. A random-effect meta-analysis estimated the overall treatment effect at standardized mean difference = 0.56 (CI: 0.41 to 0.71, P < .0001). However, the methodological quality of the studies was poor. Conclusions. The analyzed studies give some evidence that Iscador treatment might have beneficial short-time effects on QoL-associated dimensions and psychosomatic self-regulation.

Review article: Influence of Viscum album L (European mistletoe) extracts on quality of life in cancer patients: a systematic review of controlled clinical studies

OBJECTIVE

To evaluate controlled clinical studies on the efficacy and effectiveness of Viscum album for quality of life (QoL) in cancer.

MATERIALS AND METHODS

The authors conducted a search of 7 electronic databases and reference lists and had extensive consultations with experts. They carried out a criteria-based assessment of methodological study quality.

RESULTS

The authors identified 26 randomized controlled trials (RCTs) and 10 non-RCTs that investigated the influence of V album extracts (VAEs) on QoL in malignant diseases; 26 studies assessed patient-reported QoL. Questionnaires were mostly well established and validated. Half of the studies investigated VAEs concomitant with chemotherapy, radiotherapy, or surgery. Some studies were well designed, whereas others had minor or major methodological weaknesses. Among the 26 RCTs, 22 reported a QoL benefit, 3 indicated no difference, and 1 did not report any result. All the non-RCTs reported a QoL benefit. Of the studies with higher methodological quality, most reported a benefit, whereas 1 found no difference. Improvements were mainly in regard to coping, fatigue, sleep, exhaustion, energy, nausea, vomiting, appetite, depression, anxiety, ability to work, and emotional and functional well-being in general and, less consistently, in regard to pain, diarrhea, general performance, and side effects of conventional treatments. VAEs were well tolerated.

CONCLUSIONS

VAEs seem to have an impact on QoL and reduction of side effects of conventional therapies (chemotherapy, radiation) in experimental trials as well as in routine daily application. The influence on fatigue especially should be investigated further.

Survival of cancer patients treated with mistletoe extract (Iscador): a systematic literature review

Background

In Europe, extracts from Viscum album (VA-E), the European white-berry mistletoe, are widely used to treat patients with cancer.

Methods

We searched several databases such as Cochrane, EMBASE, NCCAM, NLM, DIMDI, CAMbase, and Medline. Inclusion criteria were controlled clinical studies on parameters associated with survival in cancer patients treated with Iscador. Outcome data were extracted as they were given in the publication, and expressed as hazard ratios (HR), their logarithm, and the respective standard errors using standard formulas.

Results

We found 49 publications on the clinical effects of Iscador usage on survival of cancer patients which met our criteria. Among them, 41 studies and strata provided enough data to extract hazard ratios (HR) and their standard errors (Iscador versus no extra treatment). The majority of studies reported positive effects in favour of the Iscador application. Heterogeneity of study results was moderate (I² = 38.3%, p < 0.0001). The funnel plots were considerably skewed, indicating a publication bias, a notion which is corroborated by statistical means (AC = -1.3, CI: -1.9 to -0.6, p <= 0.0001). A random effect meta-analysis estimated the overall hazard ratio at HR = 0.59 (CI: 0.53 to 0.66, p < 0.0001). Randomized studies showed less effects than non-randomized studies (ratio of HRs: 1.24, CI: 0.79 to 1.92, p = 0.35), and matched-pair studies gave significantly better results than others (ratio of HRs: 0.33; CI: 0.17 to 0.65, p = 0.0012).

Conclusions

Pooled analysis of clinical studies suggests that adjuvant treatment of cancer patients with the mistletoe extract Iscador is associated with a better survival. Despite obvious limitations, and strong hints for a publication bias which limits the evidence found in this meta-analysis, one can not ignore the fact that studies with positive effects of VA-E on survival of cancer patients are accumulating. Future studies evaluating the effects of Iscador should focus on a transparent design and description of endpoints in order to provide greater insight into a treatment often being depreciated as ineffective, but highly valued by cancer patients.

Validation of the self regulation questionnaire as a measure of health in quality of life research

OBJECTIVES

Several epidemiological studies address psychosomatic self regulation as a measure of quality of life aspects. However, although widely used in studies with a focus on complementary cancer treatment, and recognized to be associated with better survival of cancer patients, it is unclear what the self regulation questionnaire exactly measures.

DESIGN AND SETTING

In a sample of 444 individuals (27% healthy, 33% cancer, 40% other internal diseases), we performed reliability and exploratory factor analyses, and correlated the 16-item instrument with external measures such as the Hospital Anxiety and Depression Scale, the Herdecke Quality of Life questionnaire, and autonomic regulation questionnaire.

RESULTS

The 16-item pool had a very good internal consistency (Cronbach's alpha = 0.948) and satisfying/good (r subsetrt = 0.796) test-retest reliability after 3 months. Exploratory factor analysis indicated 2 sub-constructs: (1) Ability to change behaviour in order to reach goals, and (2) Achieve satisfaction and well-being. Both sub-scales correlated well with quality of life aspects, particularly with Initiative Power/Interest, Social Interactions, Mental Balance, and negatively with anxiety and depression.

CONCLUSIONS

The Self Regulation Questionnaire (SRQ) was found to be a valid and reliable tool which measures unique psychosomatic abilities. Self regulation deals with competence and autonomy and can be regarded as a problem solving capacity in terms of an active adaptation to stressful situations to restore well-being. The tool is an interesting option to be used particularly in complementary medicine research with a focus on behavioural modification.

Viscum album L. extracts in breast and gynaecological cancers: a systematic review of clinical and preclinical research

BACKGROUND

Viscum album L. extracts (VAE, European mistletoe) are a widely used medicinal plant extract in gynaecological and breast-cancer treatment.

METHODS

Systematic review to evaluate clinical studies and preclinical research on the therapeutic effectiveness and biological effects of VAE on gynaecological and breast cancer. Search of databases, reference lists and expert consultations. Criteria-based assessment of methodological study quality.

RESULTS

19 randomized (RCT), 16 non-randomized (non-RCT) controlled studies, and 11 single-arm cohort studies were identified that investigated VAE treatment of breast or gynaecological cancer. They included 2420, 6399 and 1130 patients respectively. 8 RCTs and 8 non-RCTs were embedded in the same large epidemiological cohort study. 9 RCTs and 13 non-RCTs assessed survival; 12 reported a statistically significant benefit, the others either a trend or no difference. 3 RCTs and 6 non-RCTs assessed tumour behaviour (remission or time to relapse); 3 reported statistically significant benefit, the others either a trend, no difference or mixed results. Quality of life (QoL) and tolerability of chemotherapy, radiotherapy or surgery was assessed in 15 RCTs and 9 non-RCTs. 21 reported a statistically significant positive result, the others either a trend, no difference, or mixed results. Methodological quality of the studies differed substantially; some had major limitations, especially RCTs on survival and tumour behaviour had very small sample sizes. Some recent studies, however, especially on QoL were reasonably well conducted. Single-arm cohort studies investigated tumour behaviour, QoL, pharmacokinetics and safety of VAE. Tumour remission was observed after high dosage and local application. VAE application was well tolerated. 34 animal experiments investigated VAE and isolated or recombinant compounds in various breast and gynaecological cancer models in mice and rats. VAE showed increase of survival and tumour remission especially in mice, while application in rats as well as application of VAE compounds had mixed results. In vitro VAE and its compounds have strong cytotoxic effects on cancer cells.

CONCLUSION

VAE shows some positive effects in breast and gynaecological cancer. More research into clinical efficacy is warranted.

Mistletoe Preparation Iscador: Are there Methodological Concerns with Respect to Controlled Clinical Trials?

In Europe many cancer patients use complementary therapies, particularly mistletoe. Only a few controlled clinical trials have been performed with the mistletoe preparation Iscador as a complementary treatment for cancer, many of them with medium to low quality due to methodological shortcomings. Reasons for some quality concerns, particularly discontinuation of treatment and/or participation and premature termination are analyzed. Analysis is based on controlled clinical trials dealing with Iscador. Data stem from the archive of published and ongoing research of the <> (Society for Cancer Research) in Arlesheim, Switzerland. Controlled clinical studies with cancer patients that were started after 01.01.1990 or were not completed by then have been evaluated. Fifty-six controlled studies are documented, 24 of them randomized and 32 non-randomized. Nine of the randomized studies were done by matched-pair design, the others by conventional parallel group design; six of the last were terminated prematurely primarily for slow recruitment due to patient preferences and compliance of physicians. Patient and physician preference seem to be important factors limiting recruitment for randomized trials and hence implementation. This adds to the overall unwillingness of participation by patients with serious diseases. A well-balanced mix of designs using different research methods and outcomes is suggested combined with analyses, in countries where mistletoe therapy in general or Iscador in particular is unknown or not available.

Mistletoe therapy in oncology

BACKGROUND

Mistletoe extracts are commonly used in cancer patients. It is claimed that they improve survival and quality of life (QOL) in cancer patients.

OBJECTIVES

To determine the effectiveness, tolerability and safety of mistletoe extracts given either as monotherapy or adjunct therapy for patients with cancer.

SEARCH STRATEGY

Search sources included the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 3, 2007) Cochrane Complementary Medicine Field Registry of randomized clinical trials (RCTs) and controlled clinical trials, MEDLINE, EMBASE, HEALTHSTAR, INT. HEALTH TECHNOLOGY ASSESSMENT, SOMED, AMED, BIOETHICSLINE, BIOSIS, CancerLit, CATLINE, CISCOM (August 2007). For the search the Standard Operating Procedures of the Information System in Health Economics at the German Institute for Medical Documentation and Information (DIMDI) were utilized. Reference lists of relevant articles and authors extensive files were searched for additional studies. Manufacturers of mistletoe preparations were contacted.

SELECTION CRITERIA

We included RCTs of adults with cancer of any type. The interventions were mistletoe extracts as sole treatments or given concomitantly with chemo- or radiotherapy. The outcome measures were survival times, tumor response, QOL, psychological distress, adverse effects from antineoplastic treatment and safety of mistletoe extracts.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trials for inclusion in the review. All review authors independently took part in the extraction of data and assessment of study quality and clinical relevance. Disagreements were resolved by consensus. Study authors were contacted where information was unclear. Methodological quality was narratively described and additionally assessed with the Delphi list and the Jadad score. High methodological quality was defined if six out of nine Delphi criteria, or four out of five Jadad criteria were fulfilled. Results were presented qualitatively.

MAIN RESULTS

Eighty studies were identified. Fifty-eight were excluded for various reasons, usually as there was no prospective trial design with randomised treatment allocation. Of the 21 included studies 13 provided data on survival, 7 on tumour response, 16 on measures of QOL or psychological outcomes, or prevalence of chemotherapy-related adverse effects and 12 on side effects of mistletoe treatment; overall comprising 3484 randomised cancer patients. Interventions evaluated were 5 preparations of mistletoe extracts from 5 manufacturers and one commercially not available preparation. The general reporting of RCTs was poor. Of the 13 trials investigating survival, 6 showed some evidence of a benefit, but none of them was of high methodological quality. The results of two trials in patients with melanoma and head and neck cancer gave some evidence that the used mistletoe extracts are not effective for improving survival. Of the 16 trials investigating the efficacy of mistletoe extracts for either improving QOL, psychological measures, performance index, symptom scales or the reduction of adverse effects of chemotherapy, 14 showed some evidence of a benefit, but only 2 of them including breast cancer patients during chemotherapy were of higher methodological quality. Data on side effects indicated that, depending on the dose, mistletoe extracts were usually well tolerated and had few side effects.

AUTHORS' CONCLUSIONS

The evidence from RCTs to support the view that the application of mistletoe extracts has impact on survival or leads to an improved ability to fight cancer or to withstand anticancer treatments is weak. Nevertheless, there is some evidence that mistletoe extracts may offer benefits on measures of QOL during chemotherapy for breast cancer, but these results need replication. Overall, more high quality, independent clinical research is needed to truly assess the safety and effectiveness of mistletoe extracts. Patients receiving mistletoe therapy should be encouraged to take part in future trails.