A Systematic Review and Meta-Analysis on the Survival of Cancer Patients Treated with a Fermented Viscum album L. Extract (Iscador): An Update of Findings

Pre-treatment of Cucurbita maxima 'Hokkaido orange' by Viscum album aqueous extracts in search of allelopathic potential

Viscum album L. (VA) is a unique plant with regard to its biological content. It is rich in many different metabolites with high potential in various spheres of human activity. We conducted a pilot study with 5 VA aqueous extracts of different host-tree species for pre-sowing treatment of Cucurbita maxima 'Hokkaido orange' seeds. We set the following objectives consisting of hypotheses (1) H01 is based on different effects of tested VA extracts depending on host trees and time of pre-treatment; (2) H02 focuses on the allopathic properties of the tested extracts affecting the plant growth and development by dose-response relationship; (3) A01 considers highly biologically active compounds of VA extracts also containing allelochemicals that can be used to regulate plant growth processes and create eco-friendly and resilient cities. The analysis of the stimulatory allelopathy index for 7 parameters demonstrates the direct effect of VA extracts in 62.3% of cases. The variability of the broad spectrum of effects of VA extracts of different host trees on the ontogenesis of C. maxima plants shows the presence of potential allelochemicals, resulting from the vital products of the host-parasite relationship. These effects are not fully explained by total polyphenol content and antioxidant activity as in previous studies of other mistletoe species. The authors consider this work a pilot study that expands the areas of application of VA extracts and knowledge about potential sources of allelochemicals.

Mistletoe Extract in Patients With Advanced Pancreatic Cancer

BACKGROUND

Patients with advanced pancreatic cancer have limited survival and few treatment options. We studied whether mistletoe extract (ME), in addition to comprehensive oncological treatment and palliative care, prolongs overall survival (OS) and improves health-related quality of life (HRQoL).

METHODS

The double-blind, placebo-controlled MISTRAL trial was conducted in Swedish oncology centers. The main inclusion criteria were advanced exocrine pancreatic cancer and Eastern Cooperative Oncology Group (ECOG) performance status 0-2. The subjects were randomly assigned to ME (n=143) or placebo (n=147) and were stratified by study site and by eligibility (yes/no) for palliative chemotherapy (June 2016-December 2021). ME or placebo was injected subcutaneously three times a week for nine months. The primary endpoint was overall survival (OS); one of the secondary endpoints was the HRQoL dimension global health/QoL (EORTC-QLQ-C30), as assessed at seven time points over nine months. Trial registration: EudraCT 2014-004552-64, NCT02948309.

RESULTS

No statistically significant benefit of adding ME to standard treatment was seen with respect to either OS or global health/ QoL. The adjusted hazard ratio for OS was 1.13 [0.89; 1.44], with a median survival time of 7.8 and 8.3 months for ME and placebo, respectively. The figures for the HRQoL dimension "global health/QoL" were similar in the two groups (p=0.86). The number, severity, and outcome of the reported adverse events were similar as well, except for more common local skin reactions at ME injection sites (66% vs. 1%).

CONCLUSION

ME is unlikely to have a clinically significant effect on OS or the HRQoL dimension global health/QoL when administered in patients with advanced pancreatic cancer in addition to comprehensive cancer care.

Chronobiology of Viscum album L.: a time series of daily metabolomic fingerprints spanning 27 years

Introduction: European mistletoe (Viscum album L.) has been gaining increasing interest in the field of oncology as a clinically relevant adjunctive treatment in many forms of cancer. In the field of phytopharmacology, harvesting time is pivotal. In the last century, a form of metabolomic fingerprinting based on pattern formation was proposed as a way to determine optimal harvesting times to ensure high quality of mistletoe as raw material for pharmaceutical use. In order to further evaluate the information obtained with this metabolomic fingerprinting method, we analysed a large time series of previously undigitised daily mistletoe chromatograms dating back to the 1950s. Methods: These chromatograms were scanned and evaluated using computerized image analysis, resulting in 12 descriptors for each individual chromatogram. We performed a statistical analysis of the data obtained, investigating statistical distributions, cross-correlations and time self-correlations. Results: The analysed dataset spanning about 27 years, contains 19,037 evaluable chromatograms in daily resolution. Based on the distribution and cross-correlation analyses, the 12 descriptors could be clustered into six independent groups describing different aspects of the chromatograms. One descriptor was found to mirror the annual rhythm being well correlated with temperature and a phase shift of 10 days. The time self-correlation analysis showed that most other descriptors had a characteristic self-correlation of ∼50 days, which points to further infradian rhythms (i.e., more than 24 h). Discussion: To our knowledge, this dataset is the largest of its type. The combination of this form of metabolomic fingerprinting with the proposed computer analysis seems to be a promising tool to characterise biological variations of mistletoe. Additional research is underway to further analyse the different rhythms present in this dataset.

A randomized placebo-controlled double-blinded study comparing oral and subcutaneous administration of mistletoe extract for the treatment of equine sarcoid disease

BACKGROUND

Equine sarcoids (ES) are the most common cutaneous tumors in equids. Systemic treatment options are sparse. Subcutaneous (SC) injections of Viscum album extract (VAE) demonstrate efficacy as a systemic treatment directed against ES.

OBJECTIVES/AIM

To critically assess the therapeutic efficacy of orally administered VAE.

ANIMALS

Forty-five ES-affected, privately owned, 3-12 year-old horses.

METHODS

A 3-armed randomized placebo-controlled, double-blinded study was conducted in a double-dummy design. Horses were subjected to oral administration and SC injections of either VAE or placebo (VAE oral/placebo SC, VAE SC/placebo oral, placebo oral/placebo SC) over a 7-month treatment period. Primary endpoint was the change of baseline of a composite index of ES number and ES area after 14 months. Second endpoint was the clinical response.

RESULTS

No statistically significant difference in the composite endpoint between the 3 study arms was found. The primary endpoint showed 4 (27%) horses in the VAE oral group with complete ES regression, 3 (21%) in the VAE SC injection group, and 2 (13%) in the placebo group. The clinical response revealed complete or partial regression in 6 horses of the oral VAE group (40%), 4 of the SC injection group (29%), and 4 of the placebo group (25%). Direct comparison of oral VAE and placebo showed an odds ratio, stratified for prognosis of 2.16 (95%-CI: 0.45-10.42) and a P-value of 0.336.

CONCLUSION AND CLINICAL IMPORTANCE

Oral administration of VAE is well tolerated. No statistically significant difference in the effectiveness of systemic VAE versus placebo against ES was found.

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.

Patients with Advanced or Metastasised Non-Small-Cell Lung Cancer with Viscum album L. Therapy in Addition to PD-1/PD-L1 Blockade: A Real-World Data Study

Immunotherapy with PD-1/PD-L1 inhibitors has significantly improved the survival rates of patients with metastatic non-small-cell lung cancer (NSCLC). Results of a real-world data study investigating add-on VA (Viscum album L.) to chemotherapy have shown an association with the improved overall survival of patients with NSCLC. We sought to investigate whether the addition of VA to PD-1/PD-L1 inhibitors in patients with advanced or metastasised NSCLC would have an additional survival benefit. In the present real-world data study, we enrolled patients from the accredited national registry, Network Oncology, with advanced or metastasised NSCLC. The reporting of data was performed in accordance with the ESMO-GROW criteria for the optimal reporting of oncological real-world evidence (RWE) studies. Overall survival was compared between patients receiving PD-1/PD-L1 inhibitor therapy (control, CTRL group) versus the combination of anti-PD-1/PD-L1 therapy and VA (combination, COMB group). An adjusted multivariate Cox proportional hazard analysis was performed to investigate variables associated with survival. From 31 July 2015 to 9 May 2023, 415 patients with a median age of 68 years and a male/female ratio of 1.2 were treated with anti-PD-1/PD-L1 therapy with or without add-on VA. Survival analyses included 222 (53.5%) patients within the CRTL group and 193 (46.5%) in the COMB group. Patients in the COMB group revealed a median survival of 13.8 months and patients in the CRTL group a median survival of 6.8 months (adjusted hazard ratio, aHR: 0.60, 95% CI: 0.43-0.85, p = 0.004) after adjustment for age, gender, tumour stage, BMI, ECOG status, oncological treatment, and PD-L1 tumour proportion score. A reduction in the adjusted hazard of death by 56% was seen with the addition of VA (aHR 0.44, 95% CI: 0.26-0.74, p = 0.002) in patients with PD-L1-positive tumours (tumour proportion score > 1%) treated with first-line anti-PD-1/PD-L1 therapy. Our findings suggest that add-on VA correlates with improved survival in patients with advanced or metastasised NSCLC who were treated with PD-1/PD-L1 inhibitors irrespective of age, gender, tumour stage, or oncological treatment. The underlying mechanisms may include the synergistic modulation of the immune response. A limitation of this study is the observational non-randomised study design, which only allows limited conclusions to be drawn and prospective randomised trials are warranted.

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.

Mistletoe Extracts during the Oncological Perioperative Period: A Systematic Review and Meta-Analysis of Human Randomized Controlled Trials

BACKGROUND

We aim to evaluate the safety and efficacy of mistletoe extract (ME) use during the oncological perioperative period.

METHODS

Details registered a priori on PROSPERO (CRD42018086168).

RESULTS

Seven RCTs (comprising 663 participants in nine reports) and three nonrandomized studies were included. In five RCTs, ME was evaluated as adjunctive care and the control group had no additional intervention, whereas in two RCTs, ME was compared head-to-head against common cancer treatments (i.e., etoposide or bacillus Calmette-Guérin) with the intervention groups not receiving standard care. Meta-analyses found no evidence for a difference between ME and no added therapy for mortality and recurrence (RR, 95% CI: 1.00, 0.79-1.27; and 1.03, 0.79-1.33, respectively). Two RCTs reported beneficial effects of ME on immune cells, specifically natural killer cells, in colorectal cancer, and one RCT reported quality of life improvement. Two RCTs reported ME discontinuations due to adverse events and grade 3/4 toxicities. Nevertheless, no safety signals were detected from these 10 studies. Quality appraisal revealed a substantial risk of bias.

CONCLUSIONS

Preliminary data are encouraging for mistletoe extracts, particularly in the context of colorectal cancer. However, the evidence is limited by the number of studies, an evaluation of different outcomes, and methodological limitations. Further high-quality research is warranted.

The Antioxidant Activity of Mistletoes (Viscum album and Other Species)

In addition to the European mistletoe, Viscum album, which is the most known and utilized one, there are several species commonly known as mistletoe. They are spread in various regions of the planet and are all characterized by hemiparasitism and epiphytic behaviour. The published studies evidence other similarities, including the sharing of important biological properties, with the common presence of antioxidant effects. However, whereas the European mistletoe is largely utilized in medical treatments, although with controversial aspects, the scientific knowledge and medical uses of other mistletoes are still insufficient. This review focuses on the controversial medical story of European mistletoe regarding its antioxidant activity and the potentiality of the other species named mistletoe pertaining to botanical families and genera different from Viscum.

The Anti-Inflammatory Activity of Viscum album

The therapeutic story of European mistletoe (Viscum album L.) presents a seesawing profile. In ancient times, this hemiparasitic plant was considered a panacea and even to be endowed with exceptional beneficial properties. In more recent times, despite its multiple uses in traditional medicines, some parts of the plant, in particular the berries, were considered poisonous and dangerous, including concerns of cytotoxicity, which spread serious suspicion on its medicinal utility. However, since the last century, medical interest in mistletoe has come back in force due to its utilization in clinical cancer treatments, based on its selective action on tumor cells. In Central Europe, the hydro-alcoholic extracts of European mistletoe register a relevant and continuous utilization in anthroposophic medicine, which is a holistic system that includes the utilization of phytomedicinal substances. In Switzerland and Germany, most physicians and patients use these products as complementary therapy in oncological treatments. However, despite its increasing use in this field, the results of mistletoe's use are not always convincing, and other aspects have appeared. Nowadays, products that contain mistletoe are utilized in several fields, including diet, phytotherapy, veterinary medicine and homeopathy, but in particular in cancer therapies as coadjuvant factors, in consideration of several positive effects including effects in the improvement of quality-of-life conditions and reinforcement of the immune system. In this review, based on the understanding of the association between cancer and inflammation, we propose a relationship between these recent uses of mistletoe, based on its antioxidant properties, which are supported by phytochemical and pharmacological data. The unicity of mistletoe metabolism, which is a direct consequence of its hemiparasitism, is utilized as a key interpretation element to explain its biological properties and steer its consequent therapeutic uses.

Investigations on the morpho-anatomy and histochemistry of the European mistletoe: Viscum album L. subsp. album

Viscum album L. (Santalaceae) is an important medicinal plant traditionally used to treat several diseases, including cancer therapy. This paper provides detailed morpho-anatomical characteristics of the leaves, stems and berries of Viscum album subsp. album growing as hemi-parasite on the branches of Malus domestica (Suckow) Borkh. (Rosaceae) to aid species identification and botanical characterization. Additionally, for the first time, microchemical analyses of all tissues and Energy Dispersive X-Ray Spectroscopy analyses of the calcium oxalate crystals are provided for the first time. The plant features leathery presents green leaves with parallel veins, small yellow unisexual flowers in 3-flowered cymes, and the dioecious inflorescences usually consist of three flowers, with female flowers generating white fleshy berries, in which a seed is embedded in the mucilaginous mesocarp, normally containing two embryos. Anatomically, the analyzed leaves were isobilateral and amphistomatic, and showed straight anticlinal epidermal cell walls, thick cuticles with epicuticular wax crystalloids, and paracytic stomata. The midrib is flat on both sides and has a single vascular bundle, whereas the strongly shortened petiole is concave-convex in shape and contains five bundles. The stems show a primary structure with a ring of nine vascular bundles enclosing the pith. Calcium oxalate druses and cubic and quadrangular prisms were observed in different plant parts. The results of this study provide new microscopy information that can help in the authentication of mistletoe raw materials.

Quality of Life in Breast Cancer Patients Treated With Mistletoe Extracts: A Systematic Review and Meta-Analysis

BACKGROUND

Breast cancer is the most common cancer type in women and quality of life an essential part of patients' well-being. Although the treatment with mistletoe extracts is covered by multiple cancer guidelines and reviews, it is uncertain whether mistletoe extracts can improve the quality of life in breast cancer patients. We therefore performed a systematic review and meta-analysis on this topic.

METHODS

This systematic review included randomized clinical trials (RCTs) and non-randomized studies of intervention (NRSIs) comparing the quality of life in breast cancer patients treated with mistletoe extracts as add-on therapy to control groups treated conventionally. We searched previous systematic reviews and multiple databases until January 2023. We conducted a meta-analysis and assessed the risk of bias according to the Cochrane Handbook via RoB 2 and ROBINS-I and the certainty of evidence via GRADE, respectively.

RESULTS

Nine RCTs and 7 NRSIs with 833 and 2831 participants, respectively, were included. The pre-post changes for the quality of life resulted in a pooled standardized mean difference for RCTs of SMD = 0.61 (95% CI 0.47-0.75; P < .0001) and for retrospective NRSIs of SMD = 0.46 (95% CI 0.10-0.82; P = .01). The risk of bias was low to high for the RCTs and serious for all NRSIs. The certainty of evidence was moderate for RCTs and very low for NRSIs.

DISCUSSION

Our results indicate a clinically relevant, medium-sized effect of mistletoe extracts on the quality of life in breast cancer patients which may be based on the immunomodulating effects of mistletoe extracts during chemotherapy. The limitations of evidence include the risk of bias which is mainly caused by the difficulty of blinding. Further RCTs and real-world evidence need to confirm this result, especially in the setting of neoadjuvant chemotherapy and in breast cancer survivors.

The Introspective Patient Experience of Mistletoe Therapy in Cancer: A Qualitative Study

INTRODUCTION

The introspective experience of cancer patients using mistletoe therapy has received little scientific interest, although it is crucial for a holistic understanding of this therapy. This study contributes to patient-centered research and treatment by documenting the subjective experiences of individuals undergoing mistletoe therapy.

METHODS

In this qualitative, explorative study, 20 outpatients with a history of various cancer types were recruited from Arlesheim Hospital (Arlesheim, Switzerland). All patients received subcutaneous mistletoe therapy for at least 2 years (median 7.5 years). Data was collected through 2 semi-structured, in-depth interviews per patient. Qualitative content analysis was applied to examine the data. The individual experience of mistletoe therapy was analyzed in relation to 6 predefined levels of human experience: physical, vital, emotional, mental, spiritual and social. In addition, 3 further aspects, considered as cross-dimensional perspectives, emerged out of the material: warmth, immune strengthening, and general wellbeing.

RESULTS

Data analysis revealed considerable heterogeneity among patients' experiences with mistletoe therapy. The importance of specific aspects became apparent, such as increased vitality to manage daily life, greater emotional and mental stability, warmth as a multidimensional phenomenon, feelings of safety and protection through mistletoe therapy, heightened self-awareness and improved self-care, as well as sensations of spiritual connectedness.

CONCLUSIONS

Prior to this study it had not been shown that cancer patients using mistletoe therapy do have observations on different levels of experience. These results may lead to a deeper understanding of patients receiving mistletoe therapy, enabling them to be supported in a more holistic way both during mistletoe treatment and on their life path. Further investigations into the effects of mistletoe therapy on the emotional, mental, and spiritual level are warranted.

Systematic analysis of mistletoe prescriptions in clinical studies

Purpose

Mistletoe treatment is discussed controversial as a complementary treatment for cancer patients. Aim of this systematic analysis is to assess the concept of mistletoe treatment in the clinical studies with respect to indication, type of mistletoe preparation, treatment schedule, aim of treatment, and assessment of treatment results.

Methods

In the period from August to December 2020, the following databases were systematically searched: Medline, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), PsycINFO, CINAHL, and “Science Citation Index Expanded” (Web of Science). We assessed all studies for study types, methods, endpoints and mistletoe preparations including their ways of application, host trees and dosage schedules.

Results

The search concerning mistletoe therapy revealed 3296 hits. Of these, 102 publications and at total of 19.441 patients were included. We included several study types investigating the application of mistletoe in different groups of participants (cancer patients of any type of cancer were included as well as studies conducted with healthy volunteers and pediatric patients). The most common types of cancer were breast cancer, pancreatic cancer, colorectal cancer and malignant melanoma. Randomized controlled studies, cohort studies and case reports make up most of the included studies. A huge variety was observed concerning type and composition of mistletoe extracts (differing pharmaceutical companies and host trees), ways of applications and dosage schedules. Administration varied e. g. between using mistletoe extract as sole treatment and as concomitant therapy to cancer treatment. As the analysis of all studies shows, there is no relationship between mistletoe preparation used, host tree and dosage, and cancer type.

Conclusions

Our research was not able to deviate transparent rules or guidelines with respect to mistletoe treatment in cancer care.

Viscum album mother tinctures: Harvest conditions and host trees influence the plant metabolome and the glycolytic pathway of breast cancer cells

Viscum album is a semi-parasitic plant used for over one hundred years in complementary cancer therapy. The main commercial drugs used in cancer patients' treatment are derived from the aqueous V. album extracts, whose cytotoxic potential is mostly attributed to the aqueous soluble antitumoral metabolites. On the counterpart, ethanol solvents must be used to obtain V. album mother tinctures. This methodology permits better solubilization of phenolic compounds, among others, which present antitumoral bioactivity. Recently, the metabolomics approach revealed the influence of the host tree on the V. album subspecies differentiation. To increase the scientific information about the chemical differences related to the host trees and to clarify the seasonal influences, in this study, the metabolome of 50 V. album mother tinctures from three subspecies (abietis, album, austriacum) and five host trees (Malus domestica, Quercus sp., Ulmus carpinifolia, Pinus sylvestris, Abies alba) was evaluated using summer and winter plant harvests. The in vitro cytotoxic activities were investigated in breast cancer cells (MDA-MB-231) and immortalized normal human keratinocytes (HaCaT). The summer V. album mother tinctures presented higher cytotoxic activity than winter ones. Among the summer samples, those prepared with V. album subsp. album were more cytotoxic than V. album subsp. abietis and subsp. V. album subsp. austriacum. The V. album harvested from Quercus petraea and Abies alba inhibited the key-glycolytic enzymes: hexokinase (HK), phosphofructokinase (PFK), pyruvate kinase (PK). This activity was related to a reduction in glucose uptake and lactate production, which were host-tree-time-dose-dependent. The untargeted metabolomic approach was able to discriminate the mother tinctures according to respective botanical classes and harvest season. A total of 188 metabolites were annotated under positive and negative modes. Fourteen compounds were responsible for the samples differentiation, and, to the best of our knowledge, eight were described in the Viscum album species for the first time. Our study shows the interruption of the Warburg effect as a novel antitumoral mechanism triggered by V. album mother tinctures, which is related to their metabolite profile. These results bring scientific evidence that encourages the use of V. album mother tinctures as a natural product for cancer therapy.

Mistletoe extracts for cancer treatment

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To assess the effects of mistletoe extracts (Viscum album , European mistletoe) as antitumour treatment and for supportive/palliative care in adults with cancer. We will assess whether mistletoe extracts administered alone or in combination with tumour‐specific therapies prolong progression free‐intervals (PFI) and/or overall survival (OS); enhance tumour response; alleviate treatment‐related adverse effects from conventional cancer treatment e.g. chemo‐ or radiotherapy; improve patient‐reported outcomes including health‐related QOL; and whether mistletoe extracts produce adverse effects.

Cancer-related fatigue in patients treated with mistletoe extracts: a systematic review and meta-analysis

PURPOSE

Cancer-related fatigue remains one of the most prevalent and distressing symptoms experienced by cancer patients. Effective treatments for cancer-related fatigue are needed. The objective of this meta-analysis is to determine the impact of mistletoe extracts as a pharmacological treatment for the management of cancer-related fatigue.

METHODS

We included randomized clinical trials (RCTs) and non-randomized studies of interventions (NRSIs) in cancer patients. Inclusion criteria were cancer-related fatigue severity or prevalence as an outcome and testing of mistletoe extracts compared to control groups. We searched Medline (EuropePMC), Embase, the Cochrane Central Register of Controlled Trials, Clinicaltrials.gov, and opengrey.org through October 2020. We assessed the risk of bias using the Cochrane risk of bias tools for RCTs and NRSIs and conducted a meta-analysis.

RESULTS

We performed one meta-analysis with 12 RCTs, including 1494 participants, and one meta-analysis with seven retrospective NRSIs, including 2668 participants. Heterogeneity between the studies was high in both meta-analyses. Most studies had a high risk of bias. A random-effects model showed for RCTs a standardized mean difference of -0.48 (95% confidence interval -0.82 to -0.14; p = 0.006) and for NRSIs an odds ratio of 0.36 (95% confidence interval 0.20 to 0.66; p = 0.0008).

CONCLUSION

Treatment with mistletoe extracts shows a moderate effect on cancer-related fatigue of similar size to physical activity. These results need to be confirmed by more placebo-controlled trials. Future trials should investigate different treatment durations and their effect on cancer-related fatigue in post-treatment cancer survivors.

TRIAL REGISTRATION

This meta-analysis has been registered under the PROSPERO registration number CRD42020191967 on October 7, 2020.

Additional treatment with mistletoe extracts for patients with breast cancer compared to conventional cancer therapy alone - efficacy and safety, costs and cost-effectiveness, patients and social aspects, and ethical assessment

Background

Chemotherapy is often used in the treatment of breast cancer in women. Side effects such as diarrhea, fatigue, hair loss, fever or disturbances in blood formation impair the women's quality of life. An essential treatment goal of the accompanying mistletoe therapy (MT) used in complementary medicine is to improve the health-related quality of life during cancer therapy.

Aim and methods

The HTA report on which this article is based examines the medical efficacy and safety, costs and cost-effectiveness, patient and social aspects, and ethical aspects of MT in women with breast cancer. Systematic reviews were conducted for this purpose. The search period of the literature search ranged from 2004 to October 2020.

Results

A total of 2 evidence-based medical guidelines, 3 randomized trials assessing efficacy and 1 additional non-randomized intervention trial, as well as 3 observational studies assessing safety, a cost analysis, 12 cross-sectional studies on patient aspects and 17 articles on ethical evaluation were included. Improvements in health-related quality of life compared to the control group were small to moderate. Due to the high risk of bias in the studies, it is possible that the difference is not caused by MT. One study with a small sample size showed no effect on progression-free survival after 5 years. Studies on the effect of MT on overall survival are lacking. In seven studies, local skin reactions of low and moderate severity were reported in a median of 25% (range 5 to 94%) of patients, and mild to moderate systemic reactions in a median of 2% (range 0 to 8%) of patients. A comparative cost analysis from Germany reported significantly lower medical costs within 5 years after surgery for patients with MT than for patients without MT, but the underlying observational study did not control for systematic bias. With regard to patient aspects, the frequency of use and the reasons for use from the patient's or practitioner's point of view were mainly investigated. A median of 25% (range 7 to 46%) of patients with breast cancer and 29% (range 29 to 79%) of treatment providers use MT. The main motivations of patients for use were to reduce side effects, strengthen the immune system and take an active role in the treatment process. Patients felt insufficiently advised. Studies on other aspects are lacking. The ethical evaluation was able to identify 6 overarching themes; the central challenge is the insufficient evidence on efficacy and safety.

Survival of Cancer Patients Treated with Non-Fermented Mistletoe Extract: A Systematic Review and Meta-Analysis

Background:

Mistletoe extracts (ME) are used in integrative cancer care to improve quality of life and to prolong survival. ME are available from different producers and differ in pharmaceutical processing, such as fermentation. In contrast to fermented ME, the impact of unfermented extracts on the survival of cancer patients has not yet been assessed in a meta-analysis.

Methods:

We searched the databases Embase, CENTRAL, Europe PMC, Clinicaltrials.gov, Opengrey and Google Scholar, and selected controlled studies on cancer patients treated with non-fermented ME. We included randomized controlled trials (RCTs) and non-randomized studies of intervention (NRSIs). The risk of bias was assessed with Cochrane’s ROB2 and ROBINS-I; a meta-analysis was conducted.

Results:

Eleven RCTs and eight NRSIs met the inclusion criteria. The studies were heterogeneous and their ROB2 and ROBINS-I displayed a moderate and high risk of bias, respectively. For RCTs, the pooled effect estimate of non-fermented ME on survival was HR = 0.81 (95% CI 0.69-0.95, P = .01). Subgroup analyses as well as the NRSIs estimation support the robustness of the finding. When active comparators are added to the analysis, the effect estimates become non-significant.

Conclusion:

The results may indicate a positive impact of non-fermented ME on the overall survival of cancer patients. High quality RCTs are necessary to substantiate our results.

Prospero Registration:

CRD42021233177

Thermoresponsive Hydrogel Containing Viscum album Extract for Topic and Transdermal Use: Development, Stability and Cytotoxicity Activity

Viscum album L. (Santalaceae), also known as European mistletoe, is a semi-parasitic plant that grows on different host trees. Our group recently demonstrated the antitumoral activity of ethanolic V. album extracts in vitro, depending on the dose and the host tree, V. album ssp abietis from Abies alba being the most active extract. The goal of this work focused on the development of a new topical formulation containing V. album extracts, evaluation of in vitro toxicity and ex vivo skin permeation assays. The Poloxamer 407 hydrogel containing 5% of dry (VA_DEH) or aqueous (VA_AEH) extract presented dermal compatible pH and microbiological stability for 180 days. The hydrogels flow curve presented a non-linear relation, characteristic of non-Newtonian fluids, and the mean viscosity for the VA_DEH and VA_AEH was 372.5 ± 7.78 and 331.0 ± 2.83 Pa.s, respectively, being statistically different (Welch’s t test; p < 0.01). Additionally, WST-1 in vitro assays revealed a dose-dependent toxicity for both formulations and VA_DEH presented a higher activity than the VA_AEH. The promising cytotoxic potential of VA_DEH lead to the ex vivo skin permeation assay with 2.73 ± 0.19 µg/cm² of chlorogenic acid, which permeated at 8 h, showing a transdermal potential. These in vitro results support the idea that VA_DEH is a novel promising candidate for mistletoe therapy. Therefore, further in vivo and pre-clinical experiments should be performed to evaluate the safety and efficacy of this new dermic delivery system.

Clinical Practice Guideline: Complementary Medicine in the Treatment of Cancer Patients

BACKGROUND

Approximately half of all patients with cancer use at least one method of complementary medicine during or after tumor treatment. The substances most commonly taken are micronutrients, food supplements, and plant extracts.

METHODS

This guideline is based on pertinent articles retrieved by a systematic search in the Medline, Cochrane Library, Embase, PsycInfo, and Cinahl databases.

RESULTS

The evidence is offen scant for any effect of a complementary method on patientrelevant endpoints such as relief of disease symptoms, reduction of treatment side effects, or prolonged survival. Micronutrients are available in different compositions, and their dosages vary. In most studies on the use of vitamins and trace elements by cancer patients, the blood level of the substance in question was not measured before its administration, so that it remains unknown whether a deficiency was present. For this reason, no well-founded conclusion on the effects of these substances can be drawn, and their use cannot be recommended in most cases. On the other hand, there is high-level evidence supporting physical exercise by cancer patients during and after their treatment. For patients with any type of cancer, mortality is lower among those who perform more physical exercise, whether before or after they receive the diagnosis of cancer (exercise before diagnosis, hazard ratio [HR] 0.82, 95% confidence interval [CI] [0.79; 0.86]; exercise after diagnosis, HR 0.63, 95% CI [0.53; 0.75]). Physical exercise during and after treatment for cancer should, therefore, be recommended to all cancer patients.

CONCLUSION

The inherent positive attribute of complementary medicine is patient empowerment: it enables patients to help themselves in an active way even while undergoing cancer treatment, as well as afterward. To avoid risks to health, patients should be instructed about unsafe methods, asked repeatedly about their use of complementary medicine, and informed specifically about potential interactions between such interventions and their cancer treatment.

Exploring the resources of the genus Viscum for potential therapeutic applications

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Viscum comprises approximately 100 species that are mainly distributed across Africa, Asia and Europe. The extracts and preparations of Viscum species are widely used as common complementary and alternative medicines in the treatment of rheumatism and cancer.

AIM OF THE REVIEW

This review aims to explore the medicinal properties of twelve species belonging to the genus Viscum for potential therapeutic applications.

MATERIALS AND METHODS

We collected online information (including PubMed, CNKI, Google Scholar, and Web of Science) from January 1915 to April 2021 and knowledge from classical books on Chinese herbal medicines available for 12 species of the genus Viscum, including Viscum coloratum (Kom.) Nakai, Viscum album L., Viscum articulatum Burm. f., Viscum liquidambaricola Hayata, Viscum ovalifolium DC., Viscum capitellatum Sm., Viscum cruciatum Sieber ex Boiss., Viscum nudum Danser, Viscum angulatum B.Heyne ex DC., Viscum tuberculatum A.Rich., Viscum multinerve Hayata, and Viscum diospyrosicola Hayata.

RESULTS

At least 250 different compounds have been reported across twelve Viscum species, including amino acid and peptides, alkaloids, phenolic acids, flavonoids, terpenoids, carbohydrates, fatty acids, lipids, and other types of compounds. In particular, for Viscum coloratum (Kom.) Nakai and Viscum album L., the plants, preparations, and bioactive components have been thoroughly reviewed. This has allowed to elucidate the role of active components, including lectins, viscotoxins, flavonoids, terpenoids, phenolic acids, and polysaccharides, in multiple bioactivities, such as anti-cancer, anti-rheumatism arthralgia, anti-inflammation, anti-cardiovascular diseases, enhancing immunity, and anti-chemotherapy side effects. We also evaluated quality control methods based on active compounds, in vivo exposure compounds, and discriminated chemical markers.

CONCLUSIONS

This is the first report to systematically review the pharmaceutical development history, chemical composition, clinical evidence, pharmacological activity, discriminated chemical markers, in vivo exposure, and quality control on twelve distinct species of Viscum plants with medicinal properties. The significant safety and efficacy, along with the minor side effects are constantly confirmed in clinics. The genus Viscum is thus an important medicinal resource that is worth exploring and developing in future pharmacological and chemical studies.

Metabolomics by UHPLC-Q-TOF Reveals Host Tree-Dependent Phytochemical Variation in Viscum album L

Viscum album L., commonly known as European mistletoe, is a hemi-parasitic plant of the Santalaceae family. The in vitro and in vivo effects of V. album differ, according to its host tree. However, little is known about the host-dependent phytochemical diversity in V. album. In this study, the metabolic profiles of V. album ssp. album from Malus domestica Bork., Quercus robur L., and Ulmus carpinifolia Gled were compared. Leaves, stems, and berries were collected in Switzerland, by the same procedure, in September 2016 and 2017. The methanolic extracts were analyzed by ultra-performance liquid chromatography, coupled to electrospray quadrupole time-of-flight mass spectrometry in positive ionization mode. The data were submitted to partial-least square discriminant analysis (PLS-DA) and the results showed that the V. album ssp. album samples were clustered into three groups, according to the three distinct host trees. Seven compounds, with high VIP scores (variable importance in projection), were responsible for this differentiation. The following four compounds were detected in both the harvest years: arginine, pipecolic acid or lysine, dimethoxycoumarin, and sinapyl alcohol, suggesting their use as host specific V. album biomarkers. The present work highlights the importance of standardized harvest and analytical procedures for the reproducibility of the chemical results of herbal materials.

Long-Term Survival of a Patient with Recurrent Dedifferentiated High-Grade Liposarcoma of the Retroperitoneum Under Adjuvant Treatment with Viscum album L. Extract: A Case Report

Retroperitoneal sarcomas are rare. Dedifferentiated liposarcomas (DDLs) are high-grade tumors with a high propensity for local recurrence and metastasis and are associated with reduced survival. Radical resection remains the standard treatment of sarcomas. Meanwhile, Viscum album L. extract (VAE) is used in cancer patients owing to its cytostatic and immunomodulating effects and to its ability to improve patients’ quality of life.

Anthroposophic Medicine: A Short Monograph and Narrative Review-Foundations, Essential Characteristics, Scientific Basis, Safety, Effectiveness and Misconceptions

INTRODUCTION

Anthroposophic medicine is a form of integrative medicine that originated in Europe but is not well known in the US. It is comprehensive and heterogenous in scope and remains provocative and controversial in many academic circles. Assessment of the nature and potential contribution of anthroposophic medicine to whole person care and global health seems appropriate.

METHODS

Because of the heterogenous and multifaceted character of anthroposophic medicine, a narrative review format was chosen. A Health Technology Assessment of anthroposophic medicine in 2006 was reviewed and used as a starting point. A Medline search from 2006 to July 2020 was performed using various search terms and restricted to English. Books, articles, reviews and websites were assessed for clinical relevance and interest to the general reader. Abstracts of German language articles were reviewed when available. Reference lists of articles and the author's personal references were also consulted.

RESULTS

The literature on anthroposophic medicine is vast, providing new ways of thinking, a holistic view of the world, and many integrating concepts useful in medicine. In the last ∼20 years there has been a growing research base and implementation of many anthroposophical concepts in the integrated care of patients. Books and articles relevant to describing the foundations, scientific status, safety, effectiveness and criticisms of anthroposophic medicine are discussed.

DISCUSSION

An objective and comprehensive analysis of anthroposophic medicine finds it provocative, stimulating and potentially fruitful as an integrative system for whole person care, including under-recognized life processes and psychospiritual aspects of human beings. It has a legitimate, new type of scientific status as well as documented safety and effectiveness in some areas of its multimodal approach. Criticisms and controversies of anthroposophic medicine are often a result of lack of familiarity with its methods and approach and/or come from historically fixed ideas of what constitutes legitimate science.

Comprehensive Metabolome Analysis of Fermented Aqueous Extracts of Viscum album L. by Liquid Chromatography-High Resolution Tandem Mass Spectrometry

Fermented aqueous extracts of Viscum album L. are widely used for cancer treatment in complementary medicine. The high molecular weight compounds viscotoxins and lectins are considered to be the main active substances in the extracts. However, a vast number of small molecules (≤1500 Da) is also expected to be present, and few studies have investigated their identities. In this study, a comprehensive metabolome analysis of samples of fermented aqueous extracts of V. album from two host tree species (Malus domestica and Pinus sylvestris), both prepared by two pharmaceutical manufacturing processes, was performed by liquid chromatography-high resolution tandem mass spectrometry (LC-HRMS/MS). A total of 212 metabolites were putatively annotated, including primary metabolites (e.g., amino acids, organic acids, etc.) and secondary metabolites (mostly phenolic compounds). A clear separation between V. album samples according to the host tree species, but not due to manufacturing processes, was observed by principal component analysis. The biomarkers responsible for this discrimination were assessed by partial least squares-discriminant analysis. Because V. album extracts from different host trees have different clinical applications, the present work highlights the possibility of characterizing the metabolome for identification and traceability of V. album fermented aqueous extracts.

Overall Survival of Nonmetastasized NSCLC Patients Treated With Add-On Viscum album L: A Multicenter Real-World Study

Background:

Recent data suggest a beneficial effect of add-on treatment with Viscum album L (VA) on the survival in cancer patients. The objective of this study was to compare the impact of standard oncological therapy plus add-on VA treatment (S+VA) versus standard oncological therapy alone (S) on the overall survival (OS) of patients with nonmetastasized non–small cell lung carcinoma (NSCLC).

Methods:

The multicenter real-world data study was conducted using data from the Network Oncology Clinical Registry. The primary end point was OS. OS and impact on hazard in both treatment groups were compared.

Results:

A total of 275 patients with stages I to IIIA NSCLC were enrolled (mean age = 67.6 years, 57.2% male patients). No significant difference of OS was observed between both groups. Even though not significant, for a subgroup of unresected patients with stage I NSCLC, adenocarcinoma or squamous cell carcinoma, a medium effect size OS improvement was observed for S+VA compared to S.

Conclusions:

Our findings support the importance of surgery as the most effective intervention in nonmetastasized NSCLC patients. Add-on VA therapy shows here no additional effect in resected patients. However, a small subgroup analysis suggests a possible role of add-on VA for nonresected subgroups. Our results complement existing knowledge on the clinical impact of add-on VA therapy in NSCLC patients and may serve as hypothesis-generating data for further examinations in this cohort. Further research could be directed towards the role of combined therapy for nonresected early-stage NSCLC.

Cost-effectiveness of real-world administration of chemotherapy and add-on Viscum album L. therapy compared to chemotherapy in the treatment of stage IV NSCLC patients

Background

For stage IV lung cancer patients receiving add-on Viscum album L. (VA) treatment an improved overall survival was detected. Information regarding cost-effectiveness (CE) for comparisons between chemotherapy (CTx) and CTx plus additive VA in stage IV lung cancer treatment is limited. The present study assessed the costs and cost-effectiveness of CTx plus VA (V) compared to CTx alone (C) for stage IV non-small cell lung cancer (NSCLC) patients treatment in a hospital in Germany.

Methods

In the observational real-world data study, data from the Network Oncology clinical registry were utilized. Enrolled stage IV lung cancer patients received the respective therapy (C or V) in a certified German Cancer Center. Cost and cost-effectiveness analyses from the hospital’s perspective were investigated on the basis of overall survival (OS) and routine financial controlling data. In addition, the incremental cost-effectiveness ratio (ICER) was calculated. The primary result of the analysis was tested for robustness in a bootstrap-based sensitivity analysis.

Results

118 patients (C: n = 86, V: n = 32) were included in the analysis, mean age 63.8 years, the proportion of male patients was 55.1%. Adjusted hospital’s total mean costs for patients from the C and V group were €16,289, 95%CI: 13,834€-18,744€ (over an adjusted mean OS time of 13.4 months) and €17,992, 95%CI: 13,658–22,326 (over an adjusted mean OS time of 19.1 months), respectively. The costs per additional OS year gained (ICER) with the V-therapy compared to C therapy were €3,586.

Conclusion

The findings of the present study suggest that the combined use of chemotherapy and VA was clinically effective and comparably cost-effective to chemotherapy alone in our analysed patient sample from the hospital’s perspective. Further randomized and prospective cost-effectiveness studies are necessary to complement our findings.

Viscum album L. homogenizer-assisted and ultrasound-assisted extracts as potential sources of bioactive compounds

Viscum album L. (Mistletoe) is one of the most famous plants in many countries utilized for several purposes. The current study aimed to describe chemical profiles and biological activities of homogenizer-assisted extract (HAE) and ultrasound-assisted extract (UAE)) of V. album parts (leaf, fruits, and seeds). Antioxidant (radical scavenging, reducing power, metal chelation, and phosphomolybdenum assays) and enzyme inhibitory properties (cholinesterases, amylase, glucosidase, and tyrosinase) were selected for biological evaluation. Chemical profiles were studied by HPLC-MS/MS and 32 compounds were identified in the extracts; caffeoylquinic acids and its derivatives, dimethylated flavonoids were the most significant compounds. Generally, the leaf extracts exhibited the best antioxidant and enzyme inhibitory effects in our tests. Multivariate analysis was performed to obtain more information for these data, then strong correlations between total bioactive compounds and tested parameters were observed. The present findings encourage us to further investigate V. album as a potential candidate for pharmaceutical and nutraceutical applications. PRACTICAL APPLICATIONS: Viscum album L. commonly called European mistletoe is a woody perennial shrub growing on coniferous trees with lathery leaves, small flowers, and white berries. It belongs to the Santalaceae R. Br. family from Europe and western/southern Asia. Traditional medicine recognizes mistletoe as a folk remedy to manage inflammation, hypertension, ulcers, and other diseases due to the presence of different bioactive compounds, among them mistletoe lectins and viscotoxins. Recent studies documented the possible therapeutic applications of Viscum extracts in association with cancer's therapy leading to improvements in health and patient's quality of life. Thus, this work gives novel data regarding the phytochemical characterizations and antioxidant/enzymatic inhibitor activities of different types of extracts from seeds, leaves, and fruits of Viscum L. obtained by homogenizer-assisted and ultrasound-assisted techniques, in order to increase the data set of potential applications in medicine.

Transiently Expressed Mistletoe Lectin II in Nicotiana benthamiana Demonstrates Anticancer Activity In Vitro

Mistletoe (Viscum album) extracts have been used as alternative and complementary therapeutic preparations in multiple cancers for decades. Mistletoe lectins (ML-I, ML-II, and ML-III) are considered to be the main anticancer components of such preparations. In the present study, ML-II was transiently expressed in Nicotiana benthamiana using the pEAQ-HT expression system. Expression levels of up to 60 mg/kg of the infiltrated plant tissue were obtained, and a three-fold increase was achieved by adding the endoplasmic reticulum (ER) retention signal KDEL to the native ML-II sequence. The native protein containing His-tag and KDEL was purified by immobilized metal affinity chromatography (IMAC) and gel filtration. We found that the recombinant ML-II lectin was glycosylated and retained its carbohydrate-binding activity. In addition, we demonstrated that plant produced ML-II displayed anticancer activity in vitro, inhibiting non-small cell lung cancer H460 and A549 cells with EC50 values of 4 and 3.5 µg/mL, respectively. Annexin V-448A and PI double staining revealed that cell cytotoxicity occurred via apoptosis induction. These results indicate that ML-II transiently expressed in N. benthamiana plants is a promising candidate as an anticancer agent, although further optimization of production and purification methods is required to enable further in vitro testing, as well as in vivo assays.

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.