Effect of inulin and fructo-oligosaccharide on the prevention of acute radiation enteritis in patients with gynecological cancer and impact on quality-of-life: a randomized, double-blind, placebo-controlled trial

Bacterial supplementation in mitigation of radiation-induced gastrointestinal damage

Pelvic irradiation, a crucial treatment for pelvic malignancies, is associated with the risk of gastrointestinal (GI) damage due to the high proliferation rate of epithelial cells. The radiosensitive gastrointestinal tract acts as a dose-limiting organ. High doses of ionizing radiation can cause inflammation and rupture of mucosal barriers and can also lead to intestinal fibrosis. Intestinal damage can cause acute to chronic complications, reducing patients' quality of life. The gut microbiota plays a vital role in maintaining gut health, and any changes in the gut microbial composition can worsen damage, emphasizing the importance of therapies that target and sustain the gut microbiota during radiotherapy. One potential strategy to prevent radiation-induced GI damage is to use bacterial supplements. Research suggests that probiotic supplementation may alleviate radiation-induced gastrointestinal damage, maintaining intestinal morphology and decreasing epithelial injury in cancer patients. The observed protective effects occur through various mechanisms, including antioxidant activities, modulation of the immune response, and preservation of gut barrier function. To optimize probiotic therapies, it is imperative to elucidate these mechanisms. The efficiency of probiotics as radioprotectors is highly dependent on the time and dose of administration, and their interaction with the host immune system is a key facet of their therapeutic potential. This review explores the potential benefits of bacterial supplementation in mitigating radiation-induced GI damage and the underlying mechanism. This highlights the need for further research to establish standardized protocols and refine probiotic supplementation strategies, underscoring the potential for enhancing therapeutic outcomes in patients undergoing pelvic radiotherapy.

Pharmacomicrobiomics in precision cancer therapy: bench to bedside

The burgeoning field of pharmacomicrobiomics offers promising insights into the intricate interplay between the microbiome and cancer, shaping responses to diverse treatment modalities. This review aims to analyze the molecular mechanisms underlying interactions between distinct microbiota types and cancer, as well as their influence on treatment outcomes. We explore how the microbiome impacts antitumor immunity, and response to chemotherapy, immunotherapy, and radiation therapy, unveiling its multifaceted roles in cancer progression and therapy resistance. Moreover, we discuss the challenges hindering the development of microbiome-based interventions in cancer therapy, including standardization, validation, and clinical translation. By synthesizing clinical evidence, we underscore the transformative potential of harnessing pharmacomicrobiomics in guiding cancer treatment decisions, paving the way for improved patient outcomes in clinical practice.

Prevention and management of radiotherapy-related toxicities in gynecological malignancies. Position paper on behalf of AIRO (Italian Association of Radiotherapy and Clinical Oncology)

Multi-modal therapies for gynecological cancers management may determine a wide range of side effects which depend on therapy-related factors and patient characteristics and comorbidities. Curative or adjuvant pelvic radiotherapy is linked with acute and late toxicity due to irradiation of organs at risk, as small and large bowel, rectum, bladder, pelvic bone, vagina and bone marrow. Successful toxicity management varies with its severity, Radiation Centre practice and experience and skills of radiation oncologists. This position paper was designed by the Italian Association of Radiation and Clinical Oncology Gynecology Study Group to provide radiation oncologists with evidence-based strategies to prevent and manage acute and late toxicities and follow-up recommendations for gynecological cancer patients submitted radiotherapy. Six workgroups of radiation oncologists with over 5 years of experience in gynecologic cancers were setup to investigate radiotherapy-related toxicities. For each topic, PubMed database was searched for relevant English language papers from January 2005 to December 2022. Titles and abstracts of results were checked to verify suitability for the document. Reference lists of selected studies and review papers were added if pertinent. Data on incidence, etiopathogenesis, prevention, treatment and follow-up of acute and late side effects for each organ at risk are presented and discussed.

Mechanisms and Intervention of Prebiotic Foods in Musculoskeletal Health

The review focuses primarily on collating and analyzing the mechanistic research data that discusses the function of prebiotics to halt the frailty of musculoskeletal system. Musculoskeletal diseases (MSDs) are frequently reported to co-occur within their own categories of conditions, such as osteoarthritis, rheumatoid arthritis, gouty arthritis, and psoriatic arthritis owing to their overlapping pathogenesis. Consequently, the same drugs are often used to manage the complications of most types. A few recent studies have addressed the therapeutic functions of gut microbes toward those commonly shared MSD pathway targets. Improving microbial diversity and enriching their population in the gut would promote the regeneration and recovery of the musculoskeletal system. Prebiotics are usually nondigestible substrates that are selectively used or digested by the gut microbes conferring health promotion. The microbial fermentation of prebiotics generates numerous host-beneficial therapeutic molecules. This study inspects the presumptive functions of plant-derived prebiotics for the growth and restoration of intestinal microbiota and the consequent improvement of skeletal health. The review also highlights the discrete functions of prebiotics against inflammation, autoimmunity, infection, physiologic overloading mechanism, and aging-associated loss of metabolism in MSD.

Microbiome in radiotherapy: an emerging approach to enhance treatment efficacy and reduce tissue injury

Radiotherapy is a widely used cancer treatment that utilizes powerful radiation to destroy cancer cells and shrink tumors. While radiation can be beneficial, it can also harm the healthy tissues surrounding the tumor. Recent research indicates that the microbiota, the collection of microorganisms in our body, may play a role in influencing the effectiveness and side effects of radiation therapy. Studies have shown that specific species of bacteria living in the stomach can influence the immune system's response to radiation, potentially increasing the effectiveness of treatment. Additionally, the microbiota may contribute to adverse effects like radiation-induced diarrhea. A potential strategy to enhance radiotherapy outcomes and capitalize on the microbiome involves using probiotics. Probiotics are living microorganisms that offer health benefits when consumed in sufficient quantities. Several studies have indicated that probiotics have the potential to alter the composition of the gut microbiota, resulting in an enhanced immune response to radiation therapy and consequently improving the efficacy of the treatment. It is important to note that radiation can disrupt the natural balance of gut bacteria, resulting in increased intestinal permeability and inflammatory conditions. These disruptions can lead to adverse effects such as diarrhea and damage to the intestinal lining. The emerging field of radiotherapy microbiome research offers a promising avenue for optimizing cancer treatment outcomes. This paper aims to provide an overview of the human microbiome and its role in augmenting radiation effectiveness while minimizing damage.

Effects of nutritional interventions on cognitive function in adult cancer survivors: A systematic review

AIM

To evaluate the effectiveness and safety of nutritional interventions (i.e. nutritional support, dietary patterns and dietary supplements) on cognitive function in cancer survivors.

DESIGN

Systematic review.

METHODS

A systematic and comprehensive search of PubMed, Web of Science, the Cochrane Library, Embase, and CINAHL was conducted from the inception until March 10, 2023. The last search was conducted on December 10, 2023.

REPORTING METHOD

PRISMA.

RESULTS

A total of 59 randomized controlled trials were included for analysis. Nutritional support, dietary patterns and dietary supplements improved cognitive function in cancer survivors with no apparent safety concerns. The anti-inflammatory diet, the fasting-mimicking diet and the web-based diet significantly improved cognitive function. Whereas the ketogenic diet or dietary advice to consume more soluble dietary fibres and less insoluble dietary fibres and lactose could not. There was evidence from dietary supplements to support the beneficial effects of polyunsaturated fatty acid supplements, traditional herbal medicines and other supplements.

CONCLUSIONS

Nutritional interventions have great promise for improving cognitive function in adult cancer survivors. Further validation of the nutritional interventions supported in this study in other survivors and exploration of more effective nutritional interventions are needed.

IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE

This work can support the construction of nutritional support interventions and dietary guidance programs to prevent cancer-related cognitive decline.

IMPACT

This work filled a gap in preventive strategies for cancer-related cognitive decline from a nutritional perspective. Nutritional support, dietary patterns, and dietary supplements can prevent cancer-related cognitive decline without serious safety concerns. This work highlighted nutritional interventions that have the potential to improve cognitive function in cancer survivors, benefiting the further construction of evidence-based nutritional intervention programs.

PROTOCOL REGISTRATION

PROSPERO.

PATIENT OR PUBLIC CONTRIBUTION

No patient or public contribution.

Colorectal cancer and inulin supplementation: the good, the bad, and the unhelpful

The prebiotic inulin has been vaunted for its potential to reduce the risk of colorectal cancer. Inulin fermentation resulting in the production of short-chain fatty acids, primarily butyrate, has been reported to be associated with properties that are beneficial for gut health and has led to an increased consumption of inulin in the Western population through processed food and over-the-counter dietary supplements. However, in clinical trials, there is limited evidence of the efficacy of inulin in preventing colorectal cancer. Moreover, recent data suggest that improper inulin consumption may even be harmful for gastro-intestinal health under certain circumstances. The main objective of this review is to provide insight into the beneficial and potentially detrimental effects of inulin supplementation in the context of colorectal cancer prevention and enhancement of treatment efficacy.

Fecal Microbiota Transplantation Repairs Radiation Enteritis Through Modulating the Gut Microbiota-Mediated Tryptophan Metabolism

Radiation enteritis is a common complication of abdominal and pelvic radiotherapy. Several previous studies showed that fecal microbiota transplantation (FMT) could alleviate radiation enteritis. In this study, we investigated the efficacy of FMT in alleviating radiation enteritis and explored the mechanisms by multi-omics approaches. Briefly, C57BL/6J mice were subjected to 9 Gy irradiation to the localized abdominal field, and randomized received FMT from healthy donor mice or saline. H&E staining of harvested small intestine showed FMT decreased epithelial injury. Radiation-induced microbiota dysbiosis, characterized by a decrease in beneficial bacteria Lactobacillaceae and Lachnospiraceae, while these bacteria were restored by FMT. Fecal metabolomics analysis revealed that FMT modulated metabolic dysregulation. Two tryptophan pathway metabolites, indole-3-acetaldehyde and N-Acetyl-5-hydroxytryptamine were decreased after irradiation, whereas these metabolites showed a pronounced recovery in mice receiving FMT. Proteomics analysis of small intestine indicated that radiation enteritis triggered immune-inflammatory responses, which were potentially mitigated by FMT. In 21 patients receiving pelvic radiotherapy for cervical cancer, those who developed enteritis (n = 15) had higher abundance in Lachnospiraceae. Moreover, Indole-3-acetaldehyde was reduced after irradiation. These findings provide insights into the therapeutic effects of FMT in radiation enteritis and highlight Lachnospiraceae and the tryptophan metabolite, Indole-3-acetaldehyde may protect against radiation enteritis.

Intestinal microecological transplantation for a patient with chronic radiation enteritis: A case report

BACKGROUND

The gut microbiota is strongly associated with radiation-induced gut damage. This study aimed to assess the effectiveness and safety of intestinal microecological transplantation for treating patients with chronic radiation enteritis.

CASE SUMMARY

A 64-year-old female with cervical cancer developed abdominal pain, diarrhea, and blood in the stool 1 year after radiotherapy. An electronic colonoscopy was performed to diagnose chronic radiation enteritis. Two courses of intestinal microecological transplantation and full-length 16S rRNA microbiological analysis were performed. The patient experienced short- and long-term relief from symptoms without adverse effects. Whole 16S rRNA sequencing revealed significant differences in the intestinal flora's composition between patient and healthy donors. Pathogenic bacteria, such as Escherichia fergusonii and Romboutsia timonensis, were more in the patient. Beneficial bacteria such as Faecalibacterium prausnitzii, Fusicatenibacter saccharivorans, Ruminococcus bromii, and Bifidobacterium longum were more in the healthy donors. Intestinal microbiota transplantation resulted in a significant change in the patient's intestinal flora composition. The composition converged with the donor's flora, with an increase in core beneficial intestinal bacteria, such as Eubacterium rectale, and a decrease in pathogenic bacteria. Changes in the intestinal flora corresponded with the patients' alleviating clinical symptoms.

CONCLUSION

Intestinal microecological transplantation is an effective treatment for relieving the clinical symptoms of chronic radiation enteritis by altering the composition of the intestinal flora. This study provides a new approach for treating patients with chronic radiation enteritis.

Effects of prebiotics, probiotics, and synbiotics on the prevention and treatment of cervical cancer: Mexican consensus and recommendations

Gut microbiota plays a crucial role in modulating immune responses, including effector response to infection and surveillance of tumors. This article summarizes the current scientific evidence on the effects of supplementation with prebiotics, probiotics, and synbiotics on high-risk human papillomavirus (HPV) infections, precancerous lesions, and various stages of cervical cancer development and treatment while also examining the underlying molecular pathways involved. Our findings indicate that a higher dietary fiber intake is associated with a reduced risk of HPV infection, while certain probiotics have shown promising results in clearing HPV-related lesions. Additionally, certain strains of probiotics, prebiotics such as inulin and fructo-oligosaccharides, and synbiotics decrease the frequency of gastrointestinal adverse effects in cervical cancer patients. These agents attain their results by modulating crucial metabolic pathways, including the reduction of inflammation and oxidative stress, promoting apoptosis, inhibiting cell proliferation, and suppressing the activity of oncogenes, thus attenuating tumorigenesis. We conclude that although further human studies are necessary, robust evidence in preclinical models demonstrates that prebiotics, probiotics, and synbiotics play an essential role in cervical cancer, from infection to carcinogenesis and its medical treatment. Consequently, we strongly recommend conducting high-quality clinical trials using these agents as adjuvants since they have proven safe.

Radiation enteropathy-related depression: A neglectable course of disease by gut bacterial dysbiosis

Radiation enteropathy (RE) is common in patients treated with radiotherapy for pelvic-abdominal cancers. Accumulating data indicate that gut commensal bacteria determine intestinal radiosensitivity. Radiotherapy can result in gut bacterial dysbiosis. Gut bacterial dysbiosis contributes to the pathogenesis of RE. Mild to moderate depressive symptoms can be observed in patients with RE in clinical settings; however, the rate of these symptoms has not been reported. Studies have demonstrated that gut bacterial dysbiosis induces depression. In the state of comorbidity, RE and depression may be understood as local and abscopal manifestations of gut bacterial disorders. The ability of comorbid depression to worsen inflammatory bowel disease (IBD) has long been demonstrated and is associated with dysfunction of cholinergic neural anti-inflammatory pathways. There is a lack of direct evidence for RE comorbid with depression. It is widely accepted that RE shares similar pathophysiologic mechanisms with IBD. Therefore, we may be able to draw on the findings of the relationship between IBD and depression. This review will explore the relationship between gut bacteria, RE, and depression in light of the available evidence and indicate a method for investigating the mechanisms of RE combined with depression. We will also describe new developments in the treatment of RE with probiotics, prebiotics, and fecal microbial transplantation.

Effect of gut microbiota modulation on sleep: a systematic review and meta-analysis of clinical trials

CONTEXT

A bidirectional relationship between gut microbiota (GM) and circadian rhythms has been proposed.

OBJECTIVE

The aim of this study was to analyze the efficacy of probiotic or prebiotic intervention on sleep quality and quantity.

DATA SOURCES

A systematic review and meta-analysis were conducted using the databases PubMed (MEDLINE), Embase, CINAHL, and Web of Science. Only randomized clinical trials written in English or Spanish were considered.

DATA EXTRACTION

The initial search resulted in 219 articles. Following the removal of duplicates and consideration of the selection criteria, 25 articles were selected for the systematic review and 18 articles for the meta-analysis.

DATA ANALYSIS

Microbiota modulation was not demonstrated to be associated with significant improvement in sleep quality in the present meta-analysis (P = 0.31). In terms of sleep duration, the meta-analysis found no improvement due to GM modulation (P = 0.43).

CONCLUSION

The results of this meta-analysis indicate that there is still insufficient evidence to support the relationship between GM modulation and improved sleep quality. While several studies assume that including probiotics in the diet will undoubtedly improve sleep quality, more research is needed to fully understand this phenomenon.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42021245118.

The effect of nutritional interventions in acute radiation-induced diarrhoea in patients with primary pelvic cancer: A systematic review

Acute radiation-induced diarrhoea (RID) is a well-known side effect of external radiation therapy for pelvic cancer. Acute RID is an unresolved clinical problem in approximately 80% of patients. We investigated the effect of nutritional interventions on acute RID in patients with pelvic cancer treated with curative radiotherapy. A search was conducted using PubMed, Embase.com, CINAHL, and Cochrane Library, from 1 January 2005 until 10 October 2022. We included randomised controlled trials or prospective observational studies. Eleven of the 21 identified studies had low quality of evidence, mainly because of low patient numbers distributed among several cancer diagnoses, and non-systematic assessment of acute RID. Interventions included probiotics (n = 6), prebiotics (n = 6), glutamine (n = 4), and others (n = 5). Five studies, of which two provided high quality evidence, showed that probiotics improved acute RID. Future well-designed studies investigating the effects of probiotics on acute RID are warranted. PROSPERO ID: CRD42020209499).

The gut microbiota as a booster for radiotherapy: novel insights into radio-protection and radiation injury

Approximately 60-80% of cancer patients treated with abdominopelvic radiotherapy suffer post-radiotherapy toxicities including radiation enteropathy and myelosuppression. Effective preventive and therapeutic strategies are lacking for such radiation injury. The gut microbiota holds high investigational value for deepening our understanding of the pathogenesis of radiation injury, especially radiation enteropathy which resembles inflammatory bowel disease pathophysiology and for facilitating personalized medicine by providing safer therapies tailored for cancer patients. Preclinical and clinical data consistently support that gut microbiota components including lactate-producers, SCFA-producers, indole compound-producers and Akkermansia impose intestinal and hematopoietic radio-protection. These features serve as potential predictive biomarkers for radiation injury, together with the microbial diversity which robustly predicts milder post-radiotherapy toxicities in multiple types of cancer. The accordingly developed manipulation strategies including selective microbiota transplantation, probiotics, purified functional metabolites and ligands to microbe-host interactive pathways are promising radio-protectors and radio-mitigators that merit extensive validation in clinical trials. With massive mechanistic investigations and pilot clinical trials reinforcing its translational value the gut microbiota may boost the prediction, prevention and mitigation of radiation injury. In this review, we summarize the state-of-the-art landmark researches related with radio-protection to provide illuminating insights for oncologists, gastroenterologists and laboratory scientists interested in this overlooked complexed disorder.

Exploiting dietary fibre and the gut microbiota in pelvic radiotherapy patients

With an ageing population, there is an urgent need to find alternatives to current standard-of-care chemoradiation schedules in the treatment of pelvic malignancies. The gut microbiota may be exploitable, having shown a valuable role in improving patient outcomes in anticancer immunotherapy. These bacteria feed on dietary fibres, which reach the large intestine intact, resulting in the production of beneficial metabolites, including short-chain fatty acids. The gut microbiota can impact radiotherapy (RT) treatment responses and itself be altered by the radiation. Evidence is emerging that manipulation of the gut microbiota by dietary fibre supplementation can improve tumour responses and reduce normal tissue side effects following RT, although data on tumour response are limited to date. Both may be mediated by immune and non-immune effects of gut microbiota and their metabolites. Alternative approaches include use of probiotics and faecal microbiota transplantation (FMT). Current evidence will be reviewed regarding the use of dietary fibre interventions and gut microbiota modification in improving outcomes for pelvic RT patients. However, data regarding baseline (pre-RT) gut microbiota of RT patients and timing of dietary fibre manipulation (before or during RT) is limited, heterogenous and inconclusive, thus more robust clinical studies are required before these strategies can be applied clinically.

High-yield production and purification of prebiotic inulin-type fructooligosaccharides

Due to the health-promoting effects and functional properties of inulin-type fructooligosaccharides (I-FOS), the global market for I-FOS is constantly growing. Hence, there is a continuing demand for new, efficient biotechnological approaches for I-FOS production. In this work, crude inulosucrase InuGB-V3 from Lactobacillus gasseri DSM 20604 was used to synthesize I-FOS from sucrose. Supplementation with 1 mM CaCl2, a pH of 3.5–5.5, and an incubation temperature of 40 °C were found to be optimal production parameters at which crude inulosucrase showed high conversion rates, low sucrose hydrolysis, and excellent stability over 4 days. The optimal process conditions were employed in cell-free bioconversion reactions. By elevating the substrate concentration from 570 to 800 g L−1, the I-FOS concentration and the synthesis of products with a low degree of polymerization (DP) could be increased, while sucrose hydrolysis was decreased. Bioconversion of 800 g L−1 sucrose for 20 h resulted in an I-FOS-rich syrup with an I-FOS concentration of 401 ± 7 g L−1 and an I-FOS purity of 53 ± 1% [w/w]. I-FOS with a DP of 3–11 were synthesized, with 1,1-kestotetraose (DP4) being the predominant transfructosylation product. The high-calorie sugars glucose, sucrose, and fructose were removed from the generated I-FOS-rich syrup using activated charcoal. Thus, 81 ± 5% of the initially applied I-FOS were recovered with a purity of 89 ± 1%.

Recent Research and Application Prospect of Functional Oligosaccharides on Intestinal Disease Treatment

The intestinal tract is an essential digestive organ of the human body, and damage to the intestinal barrier will lead to various diseases. Functional oligosaccharides are carbohydrates with a low degree of polymerization and exhibit beneficial effects on human intestinal health. Laboratory experiments and clinical studies indicate that functional oligosaccharides repair the damaged intestinal tract and maintain intestinal homeostasis by regulating intestinal barrier function, immune response, and intestinal microbial composition. Functional oligosaccharides treat intestinal disease such as inflammatory bowel disease (IBD) and colorectal cancer (CRC) and have excellent prospects for therapeutic application. Here, we present an overview of the recent research into the effects of functional oligosaccharides on intestinal health.

The Role of the Human Gut Microbiome in Inflammatory Bowel Disease and Radiation Enteropathy

The human gut microbiome plays a key role in regulating host physiology. In a stable state, both the microbiota and the gut work synergistically. The overall homeostasis of the intestinal flora can be affected by multiple factors, including disease states and the treatments given for those diseases. In this review, we examine the relatively well-characterised abnormalities that develop in the microbiome in idiopathic inflammatory bowel disease, and compare and contrast them to those that are found in radiation enteropathy. We discuss how these changes may exert their effects at a molecular level, and the possible role of manipulating the microbiome through the use of a variety of therapies to reduce the severity of the underlying condition.

Diet-microbiome interactions in cancer treatment: Opportunities and challenges for precision nutrition in cancer

Dietary patterns contribute to cancer risk. Separately, microbial factors influence the development of several cancers. However, the interaction of diet and the microbiome and their joint contribution to cancer treatment response needs more research. The microbiome significantly impacts drug metabolism, immune activation, and response to immunotherapy. One of the critical factors affecting the microbiome structure and function is diet. Data demonstrate that the diet and microbiome composition affects the immune response. Moreover, malnutrition is a significant confounder to cancer therapy response. There is little understanding of the interaction of malnutrition with the microbiome in the context of cancer. This review aims to address the current knowledge of dietary intake patterns and malnutrition among cancer patients and the impact on treatment outcomes. Second, this review will provide evidence linking the microbiome to cancer treatment response and provide evidence of the potentially strong effect that diet could have on this interaction. This review will formulate critical questions that will need further research to understand the diet-microbiome relationship in cancer treatment response and directions for future research to guide us to precision nutrition therapy to improve cancer outcomes.

Cancer pharmacomicrobiomics: targeting microbiota to optimise cancer therapy outcomes

Despite the promising advances in novel cancer therapy such as immune checkpoint inhibitors (ICIs), limitations including therapeutic resistance and toxicity remain. In recent years, the relationship between gut microbiota and cancer has been extensively studied. Accumulating evidence reveals the role of microbiota in defining cancer therapeutic efficacy and toxicity. Unlike host genetics, microbiota can be easily modified via multiple strategies, including faecal microbiota transplantation (FMT), probiotics and antibiotics. Preclinical studies have identified the mechanisms on how microbes influence cancer treatment outcomes. Clinical trials have also demonstrated the potential of microbiota modulation in cancer treatments. Herein, we review the mechanistic insights of gut microbial interactions with chemotherapy and ICIs, particularly focusing on the interplay between gut bacteria and the pharmacokinetics (eg, metabolism, enzymatic degradation) or pharmacodynamics (eg, immunomodulation) of cancer treatment. The translational potential of basic findings in clinical settings is then explored, including using microbes as predictive biomarkers and microbial modulation by antibiotics, probiotics, prebiotics, dietary modulations and FMT. We further discuss the current limitations of gut microbiota modulation in patients with cancer and suggest essential directions for future study. In the era of personalised medicine, it is crucial to understand the microbiota and its interactions with cancer. Manipulating the gut microbiota to augment cancer therapeutic responses can provide new insights into cancer treatment.

The effect of nutritional interventions involving dietary counselling on gastrointestinal toxicities in adults receiving pelvic radiotherapy - A systematic review

Gastrointestinal (GI) toxicities are common in patients receiving radiotherapy (RT) to the pelvis. This systematic review aims to evaluate the effectiveness of nutritional interventions involving dietary counselling (DC) on GI toxicities in patients receiving pelvic RT. The search method entailed two phases to retrieve studies. Articles from a previous Cochrane review by Lawrie et al. 2018 were assessed for inclusion. An updated systematic search was then conducted to retrieve articles published between 2013 and 2020 from five electronic databases (MEDLINE, EMBASE, CINAHL, CENTRAL and Scopus). The inclusion criteria entailed randomised controlled trials involving adults ≥18 years, undergoing curative pelvic RT, receiving a nutritional intervention involving DC with or without supplements. DC was defined as written or face-to-face dietary advice provided before or during RT. Outcomes included GI toxicities reported by validated assessment tools. The Academy of Nutrition and Dietetics Quality Criteria Checklist was utilised to assess quality and risk of bias. Of 1922 studies retrieved, 12 articles encompassing 11 individual RCTs were included. Seven studies included a supplement in addition to DC. Supplements included probiotics, prebiotics, probiotic + soluble fibre, high protein liquid supplement and fat emulsion. Of the 11 studies, one involved individualised DC, and the remaining studies prescribed consumption or avoidance of fats, fibre, lactose, protein and FODMAP. The most common toxicities reported were diarrhoea (n = 11), pain/cramping (n = 9) and bloating/flatulence (n = 5). Three studies stated an improvement in diarrhoea incidence. Results varied between studies. Further quality studies are required to assess the effectiveness of DC, in particular individualised DC on GI toxicities in patients receiving pelvic RT.

Role of dietary fiber in safeguarding intestinal health after pelvic radiotherapy

PURPOSE OF REVIEW

Damage to healthy bowel tissue during pelvic radiotherapy can produce devastating and life-long changes in bowel function. The surging interest in microbiota and its importance for our wellbeing has generated a bulk of research highlighting how the food we consume impacts bowel health and disease. Dietary fiber is known to promote bowel health, yet there is a limited number of studies on dietary fiber in connection to pelvic radiotherapy. Here, we review some of the literature on the subject and present the most recent publications in the field.

RECENT FINDINGS

Advice given concerning dietary fiber intake during and after pelvic radiotherapy are inconsistent, with some clinics suggesting a decrease in intake and others an increase. Recent animal studies provide a solid support for a protective role of dietary fiber with regards to intestinal health after pelvic radiotherapy, mainly through its impact on the microbiota. No clinical study has yet provided unambiguous evidence for a similar function of dietary fiber in humans undergoing pelvic radiotherapy.

SUMMARY

There is a lack of evidence behind the dietary advice given to cancer survivors suffering from radiation-induced bowel dysfunction, and high-quality and well powered studies with long follow-up times are needed.

The Impact of Gut Microbiota on Radiation-Induced Enteritis

Radiotherapy is an important treatment for abdominal tumors. A critical side effect for this therapy is enteritis. In this review, we aim to summarize recent findings in radiation enteritis, in particular the role of gut microbiota dysbiosis in the development and therapy of the disease. Gut microbiota dysbiosis plays an important role in the occurrence of various diseases, such as radiation enteritis. Abdominal radiation results in changes in the composition of microbiota and reduces its diversity, which is mainly reflected in the decrease of Lactobacillus spp. and Bifidobacterium spp. and increase of Escherichia coli and Staphylococcus spp. Gut microbiota dysbiosis aggravates radiation enteritis, weakens intestinal epithelial barrier function, and promotes inflammatory factor expression. Pathogenic Escherichia coli induce the rearrangement and redistribution of claudin-1, occludin, and ZO-1 in tight junctions, a critical component in intestinal epithelial barrier. In view of the role that microbiome plays in radiation enteritis, we believe that intestinal flora could be a potential biomarker for the disease. Correction of microbiome by application of probiotics, fecal microbiota transplantation (FMT), and antibiotics could be an effective method for the prevention and treatment of radiation-induced enteritis.

Review: Effect of Gut Microbiota and Its Metabolite SCFAs on Radiation-Induced Intestinal Injury

Gut microbiota is regarded as the second human genome and forgotten organ, which is symbiotic with the human host and cannot live and exist alone. The gut microbiota performs multiple physiological functions and plays a pivotal role in host health and intestinal homeostasis. However, the gut microbiota can always be affected by various factors and among them, it is radiotherapy that results in gut microbiota ¹²dysbiosis and it is often embodied in a decrease in the abundance and diversity of gut microbiota, an increase in harmful bacteria and a decrease in beneficial bacteria, thereby affecting many disease states, especially intestine diseases. Furthermore, gut microbiota can produce a variety of metabolites, among which short-chain fatty acids (SCFAs) are one of the most abundant and important metabolites. More importantly, SCFAs can be identified as second messengers to promote signal transduction and affect the occurrence and development of diseases. Radiotherapy can lead to the alterations of SCFAs-producing bacteria and cause changes in SCFAs, which is associated with a variety of diseases such as radiation-induced intestinal injury. However, the specific mechanism of its occurrence is not yet clear. Therefore, this review intends to emphasize the alterations of gut microbiota after radiotherapy and highlight the alterations of SCFAs-producing bacteria and SCFAs to explore the mechanisms of radiation-induced intestinal injury from the perspective of gut microbiota and its metabolite SCFAs.

Nutritional Interventions Targeting Gut Microbiota during Cancer Therapies

The gut microbiome is increasingly being recognized for its influence on intestinal and extra-intestinal disorders such as cancer. Today, diet is the most studied environmental modulator of gut microbiota, capable of altering or improving it in terms of richness and diversity. Recent evidence from several preclinical and clinical trials suggested that gut microbiota composition could modulate cancer therapies (toxicities, treatment responses) and vice versa. This review highlights the latest research on the bidirectional associations between gut microbiota and cancer. We also dissect the role of gut microbiota during cancer therapies in terms of toxicity and treatment response and, in turn, how cancer therapies could impact gut microbiota composition and functions. In this context, we summarize the state-of-the-art research regarding the role of various nutritional interventions-prebiotics, dietary strategies, and dietary restrictions-as cutting-edge possibilities to modulate gut microbiota during cancer therapies.

Acute Radiation Syndrome and the Microbiome: Impact and Review

Study of the human microbiota has been a centuries-long endeavor, but since the inception of the National Institutes of Health (NIH) Human Microbiome Project in 2007, research has greatly expanded, including the space involving radiation injury. As acute radiation syndrome (ARS) is multisystemic, the microbiome niches across all areas of the body may be affected. This review highlights advances in radiation research examining the effect of irradiation on the microbiome and its potential use as a target for medical countermeasures or biodosimetry approaches, or as a medical countermeasure itself. The authors also address animal model considerations for designing studies, and the potential to use the microbiome as a biomarker to assess radiation exposure and predict outcome. Recent research has shown that the microbiome holds enormous potential for mitigation of radiation injury, in the context of both radiotherapy and radiological/nuclear public health emergencies. Gaps still exist, but the field is moving forward with much promise.

Gut Microbiota: Influence on Carcinogenesis and Modulation Strategies by Drug Delivery Systems to Improve Cancer Therapy

Gut microbiota have close interactions with the host. It can affect cancer progression and the outcomes of cancer therapy, including chemotherapy, immunotherapy, and radiotherapy. Therefore, approaches toward the modulation of gut microbiota will enhance cancer prevention and treatment. Modern drug delivery systems (DDS) are emerging as rational and promising tools for microbiota intervention. These delivery systems have compensated for the obstacles associated with traditional treatments. In this review, the essential roles of gut microbiota in carcinogenesis, cancer progression, and various cancer therapies are first introduced. Next, advances in DDS that are aimed at enhancing the efficacy of cancer therapy by modulating or engineering gut microbiota are highlighted. Finally, the challenges and opportunities associated with the application of DDS targeting gut microbiota for cancer prevention and treatment are briefly discussed.

Natural substances in cancer—do they work?

Owing to anticancer properties of selected natural substances, it is assumed that they have potential to be used in oncological therapy. Here, the recently proven effects of the selected natural polyphenols, resveratrol and curcumin, are described. Secondly, the potential of probiotics and prebiotics in modulation of immunological response and/or enhancing the chemotherapeutic treatments is reported based on the recent clinical trials. Further, the chapter presents current knowledge regarding the targeted supplementation of the patient with probiotic bacteria and known efficacy of probiotics to support immunotherapy. The major clinical trials are listed, aiming to verify whether, and to which extent the manipulation of patient’s microbiome can improve the outcome of chemotherapies. In the end, a potential of natural substances and feed ingredients to pose epigenetic changes is highlighted. The chapter provides an insight into the scientific proofs about natural bioactive substances in relation to cancer treatment, leaded by the question – do they really work?

Dietary Habits of Women with Gynecological Cancer before, during and after Treatment: A Long-Term Prospective Cohort Study

BACKGROUND AND AIM

Over 21,000 new cases of gynecological cancer are diagnosed annually in the United Kingdom. There is evidence of cancer patients altering their eating habits before and during treatment. Some women with gynecological cancer make conscious decisions to change their diet as self-management for their cancer symptoms and to adopt a healthier lifestyle. Little is known about the impact of treatment on dietary habits. This study aimed to identify and describe the dietary habits of women with gynecological cancer before, during and after treatment.

METHODS

This was a longitudinal prospective cohort study using seven-day food diaries to collect dietary intake data before treatment and up to two years after gynecological cancer treatment. Nutritics© software was used for analysis of the diaries. A general linear mixed model was used for the statistical analysis, adjusted for multiple comparisons.

RESULTS

15 women with gynecological cancer participated; 69 food diaries were analyzed. There were no statistically significant changes in dietary habits or weight for this cohort during the two-year follow-up, except for caffeine intake which increased at 2 years (p < 0.05).

CONCLUSIONS

Despite the importance of maintaining a healthy dietary intake and weight after cancer treatment, participants' diets did not change.

A systematic review of home-based dietary interventions during radiation therapy for cancer

•

This is the first systematic review of dietary recommendations for patients receiving radiation therapy.

•

High fiber diet may improve diarrhea in pelvic cancer patients.

•

Limited data to support safe and efficacious use of dietary interventions during radiotherapy.

•

No dietary intervention has been shown to improve survival.

Purpose

Our objectives are to assess (1) the acceptability and feasibility of dietary interventions for patients undergoing radiation therapy (RT), and (2) the impact of dietary interventions on patient reported outcomes, toxicities, and survival.

Methods

A PICOS/PRISMA/MOOSE selection protocol was used to include articles that evaluate adding dietary interventions to patients receiving RT. Acceptability was defined as (# accepting/# approached); feasibility was (# completing/# approached). Patient-reported outcomes were reported based on questionnaires used in each study and survival was measured from the date of diagnosis until death in each study. Level of evidence was assessed with Center for Evidence-Based Medicine (CEBM) criteria.

Results

Sixteen articles were included; among these, 2027 patients were approached regarding the intervention, and 1661 accepted (81.9%); of these, 1543 (92.9%) completed the prescribed diet + RT course. The most common cancers included were gynecological, head and neck, and gastrointestinal. For patients with pelvic cancers, a high fiber diet may improve diarrhea (CEBM level 1b). Enteral nutrition formula, including formulas with proteins such as L-arginine, lipids such as eicosapentaenoic acids, glucids, and ribonucleotides, may help prevent of malnutrition in head and neck cancer patients undergoing RT (level 2b). Vitamin C and β-carotene may reduce of xerostomia in head and neck cancer patients; however, the studies evaluating these vitamins included vitamin E, which increases all-cause mortality (level 2b). No dietary intervention for cancer patients receiving RT has been shown to improve survival.

Conclusion

There are limited data to support safe and efficacious use of dietary interventions during RT.

The Microbiome and Cancer: Creating Friendly Neighborhoods and Removing the Foes Within

The human body is colonized by the microbial cells that are estimated to be as abundant as human cells, yet their genome is roughly 100 times the human genome, providing significantly more genetic diversity. The past decade has observed an explosion of interest in examining the existence of microbiota in the human body and understanding its role in various diseases including inflammatory bowel disease, neurologic diseases, cardiovascular disorders, and cancer. Many studies have demonstrated differential community composition between normal tissue and cancerous tissue, paving the way for investigations focused on deciphering the cause-and-effect relationships between specific microbes and initiation and progression of various cancers. Also, evolving are the strategies to alter tumor-associated dysbiosis and move it toward eubiosis with holistic approaches to change the entire neighborhood or to neutralize pathogenic strains. In this review, we discuss important pathogenic bacteria and the underlying mechanisms by which they affect cancer progression. We summarize key microbiota alterations observed in multiple tumor niches, their association with clinical stages, and their potential use in cancer diagnosis and management. Finally, we discuss microbiota-based therapeutic approaches.

The role of the gut microbiome on radiation therapy efficacy and gastrointestinal complications: A systematic review

Radiation therapy (RT) is an essential component of therapy either curative or palliative armamentarium in oncology, but its efficacy varies considerably among patients through many extrinsic and intrinsic mechanisms of the tumour, which are beginning to be better understood. Recent studies have shown that the gut microbiome represents a key factor in the modulation of the systemic immune response and consequently on patients' outcome. Moreover, the emergence of biomarkers that are derived from the gut microbiota has fuelled the development of adjuvant strategies for patients treated with immunotherapy in combination or not with RT. Despite progress in development of more precise radiotherapy techniques, almost all patients undergoing RT to the abdomen, pelvis, or rectum develop acute adverse events as a consequence of several dose-limiting parameters such as the location of irradiation that may subsequently damage normal tissue including the intestinal epithelium. Several lines of evidence in preclinical models identified that vancomycin improves RT-induced gastrointestinal toxicities such as diarrhea and oral mucositis. In order to gain further insight into this rapidly evolving field, we have systematically reviewed the studies that have described how the gut microbiome may directly or indirectly modulate RT efficacy and its gastro-intestinal toxicities. Lastly, we outline current knowledge gaps and discuss potentially more satisfactory therapeutic options to restore the functionality of the gut microbiome of patients treated with RT.

Bi-Directional interactions between microbiota and ionizing radiation in head and neck and pelvic radiotherapy - clinical relevance

Purpose: Rapid developments in high throughput screening technology for the detection and identification of the human microbiota have helped in understanding its influence on human health and disease. In the recent past, several seminal studies have demonstrated the influence of microbiota on outcomes of therapy-associated radiation exposure. In this review, we highlight the concepts related to the mechanisms by which radiation alters the microbiota composition linked with radiation-associated toxicity in head and neck and pelvic regions. We further discuss specific microbial changes that can be employed as a biomarker for radiation and tumor response.Conclusion: Knowledge of the influence of microbiota in radiation response and advances in microbiota manipulation techniques would help to design personalized treatment augmenting the efficacy of radiotherapy.

Radiation enteritis: from diagnosis to management

PURPOSE OF REVIEW

As cancer treatments improve more patients than ever are living for longer with the side effects of these treatments. Radiation enteritis is a heterogenous condition with significant morbidity. The present review aims to provide a broad overview of the condition with particular attention to the diagnosis and management of the condition.

RECENT FINDINGS

Radiation enteritis appears to be more prevalent than originally thought because of patient underreporting and a lack of clinician awareness. Patient-related and treatment-related risk factors have now been identified and should be modified where possible. Medical and surgical factors have been explored, but manipulation of the gut microbiota offers one of the most exciting recent developments in disease prevention. Diagnosis and treatment are best approached in a systematic fashion with particular attention to the exclusion of recurrent malignancy and other gastrointestinal conditions. Surgery and endoscopy both offer opportunities for management of the complications of radiation enteritis. Experimental therapies offer hope for future management of radiation enteritis but large-scale human trials are needed.

SUMMARY

Radiation enteritis is an important clinical problem, but awareness is lacking amongst patients and physicians. Clinical guidelines would allow standardised management which may improve the burden of the disease for patients.

Microbiota- and Radiotherapy-Induced Gastrointestinal Side-Effects (MARS) Study: A Large Pilot Study of the Microbiome in Acute and Late-Radiation Enteropathy

PURPOSE

Radiotherapy is important in managing pelvic cancers. However, radiation enteropathy may occur and can be dose limiting. The gut microbiota may contribute to the pathogenesis of radiation enteropathy. We hypothesized that the microbiome differs between patients with and without radiation enteropathy.Experimental Design: Three cohorts of patients (n = 134) were recruited. The early cohort (n = 32) was followed sequentially up to 12 months post-radiotherapy to assess early radiation enteropathy. Linear mixed models were used to assess microbiota dynamics. The late cohort (n = 87) was assessed cross-sectionally to assess late radiation enteropathy. The colonoscopy cohort compared the intestinal mucosa microenvironment in patients with radiation enteropathy (cases, n = 9) with healthy controls (controls, n = 6). Fecal samples were obtained from all cohorts. In the colonoscopy cohort, intestinal mucosa samples were taken. Metataxonomics (16S rRNA gene) and imputed metataxonomics (Piphillin) were used to characterize the microbiome. Clinician- and patient-reported outcomes were used for clinical characterization.

RESULTS

In the acute cohort, we observed a trend for higher preradiotherapy diversity in patients with no self-reported symptoms (P = 0.09). Dynamically, diversity decreased less over time in patients with rising radiation enteropathy (P = 0.05). A consistent association between low bacterial diversity and late radiation enteropathy was also observed, albeit nonsignificantly. Higher counts of Clostridium IV, Roseburia, and Phascolarctobacterium significantly associated with radiation enteropathy. Homeostatic intestinal mucosa cytokines related to microbiota regulation and intestinal wall maintenance were significantly reduced in radiation enteropathy [IL7 (P = 0.05), IL12/IL23p40 (P = 0.03), IL15 (P = 0.05), and IL16 (P = 0.009)]. IL15 inversely correlated with counts of Roseburia and Propionibacterium.

CONCLUSIONS

The microbiota presents opportunities to predict, prevent, or treat radiation enteropathy. We report the largest clinical study to date into associations of the microbiota with acute and late radiation enteropathy. An altered microbiota associates with early and late radiation enteropathy, with clinical implications for risk assessment, prevention, and treatment of radiation-induced side-effects.See related commentary by Lam et al., p. 6280.

Efficacy of Synbiotics to Reduce Symptoms and Rectal Inflammatory Response in Acute Radiation Proctitis: A Randomized, Double-Blind, Placebo-Controlled Pilot Trial

Purpose: Evaluate whether the daily intake of synbiotics improves symptoms and rectal/systemic inflammatory response in patients with radiation-induced acute proctitis.Methods and Materials: Twenty patients who underwent three-dimensional conformal radiotherapy for prostate cancer were randomized to intake either a synbiotic powder containing Lactobacillus reuteri (10⁸ CFU) and soluble fiber (4.3 g) or placebo. EORTC QLQ-PRT23 questionnaire was applied before the beginning of radiotherapy and after the fifth, sixth, and seventh weeks of treatment, and the sum of both the complete (proctitis symptoms plus quality of life) and partial (proctitis symptoms) scores were compared. Fecal calprotectin was measured at Day 0 and in the fourth week of treatment, and serum C-reactive protein/albumin ratio were measured in the fourth week of treatment.Results: Both the complete and partial questionnaire score (median and range) were higher in the fifth and sixth weeks in the placebo group; there was a higher increase in fecal calprotectin in the placebo group and no difference comparing CRP/albumin ratio.Conclusions: Synbiotics reduce proctitis symptoms and improve quality of life by preventing rectal inflammation during radiotherapy for prostate cancer.

Effect of inulin-type fructans in patients undergoing cancer treatments: A systematic review

Background and Objective

Current studies give us inconsistent results regarding the inulin consumption in cancer patients. The results of to-date studies are summarized in this systematic review.

Methods

Web of Science (Science citation index expanded), PubMed (Medline), Embase and CENTRAL Science direct, Google scholar, Scopus and Cochrane were searched. Cochrane Collaboration's 'Risk of Bias' tool was used to assess the quality of included articles.

Results

Our search yielded 2652 studies after the elimination of duplicates. Three randomized controlled trials (RCTs), reporting results from 197 patients, were eligible for inclusion in the present systematic review. Risk of bias in these studies was assessed as high and moderate.

Conclusion

The available evidence is inconclusive regarding the effect of inulin and oligofructose on cancer outcomes. Nonetheless, possible inulin positive effects including improved stool consistency after abdomen radiotherapy and increased stool butyrate content which is involved in controlling tumor cells proliferation and apoptosis should not be denied. Further research is needed in this area before strong conclusions can be drawn.

Effects of β-Fructans Fiber on Bowel Function: A Systematic Review and Meta-Analysis

The aim of this systematic review and meta-analysis was to assess the effects of β-fructan supplementation on bowel function in healthy volunteers and patients. The search process was based on the selection of publications listed in the Pubmed and EUPMC database until December 2017, plus two unpublished studies, to identify studies evaluating the impact of β-fructans on bowel movement and stool parameters. Forty-seven publications were selected for inclusion. Primary parameter was frequency of bowel movements, evaluated by the number of defecations per day during the study period. Secondary outcomes were stool consistency, stool dry and wet weights, and transit time. Short-chain (DP < 10) β-fructans contributed to increased stool frequency (0.36 defecation +/- 0.06 per day; p < 0.001), while no significant effect was reported with long-chain (DP ≥ 10) β-fructans (-0.03 +/- 0.11, p = 0.82). A minimal increase in stool wet weight was also statistically demonstrated with short-chain β-fructans. Moreover, the meta-analysis highlighted significant differences in stool consistency in contrast to fecal dry weight after β-fructan supplementation. This systematic review and meta-analysis indicates that short-chain β-fructan supplementation has a positive effect on bowel function by significantly increasing the frequency of bowel movements.

Consensus and contentious statements on the use of probiotics in clinical practice: A south east Asian gastro-neuro motility association working team report

The concept of consuming microorganisms in the treatment of a medical condition and in health maintenance has gained much attraction, giving rise to an abundance of medical claims and of health supplements. This study identified relevant clinical questions on the therapeutic use of probiotics and reviewed the literature in irritable bowel syndrome, inflammatory bowel disease, impaired intestinal immunity, liver disease, intestinal infections, and common childhood digestive disorders. Statements were developed to address these clinical questions. A panel of experienced clinicians was tasked to critically evaluate and debate the available data. Both consensus and contentious statements are presented to provide to clinicians a perspective on the potential of probiotics and importantly their limitations.

Probiotics and mucositis

PURPOSE OF REVIEW

To provide an updated perspective on the use of probiotics as adjuvant treatment strategy for patients suffering from or at risk of developing mucositis.

RECENT FINDINGS

Studies suggest that oral and intestinal microbiota could be relevant to mucositis development and treatment, but no clear high-risk pattern has been identified and no single probiotic formulation has emerged from human clinical trials for strong recommendation. Promising results from available clinical trials suggest their use in patients with peri-implant mucositis or at risk of anticancer treatment-related oral or intestinal mucositis. In general, a positive effects of Lactobacillus species is becoming consistent, particularly Lactobacillus reuteri, in the treatment of peri-implant mucositis and Lactobacillus brevi CD2 in the prevention of chemoradiotherapy-related oral mucositis. However, several limitations still need to be addressed by future research. Nonetheless, their use appears to be safe. Therefore, decision to consider the use of probiotics ultimately depends on the preference of the clinicians.

SUMMARY

In the ongoing era of 'precision medicine', efforts should be directed toward the identification of high-risk patient populations which could benefit most from targeted interventions with probiotics enabling an improvement of clinical outcomes and quality of life in a cost-effective manner.

Probiotics for the prevention or treatment of chemotherapy- or radiotherapy-related diarrhoea in people with cancer

BACKGROUND

Treament-related diarrhoea is one of the most common and troublesome adverse effects related to chemotherapy or radiotherapy in people with cancer. Its reported incidence has been as high as 50% to 80%. Severe treatment-related diarrhoea can lead to fluid and electrolyte losses and nutritional deficiencies and could adversely affect quality of life (QoL). It is also associated with increased risk of infection in people with neutropenia due to anticancer therapy and often leads to treatment delays, dose reductions, or treatment discontinuation. Probiotics may be effective in preventing or treating chemotherapy- or radiotherapy-induced diarrhoea.

OBJECTIVES

To evaluate the clinical effectiveness and side effects of probiotics used alone or combined with other agents for prevention or treatment of chemotherapy- or radiotherapy-related diarrhoea in people with cancer.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 7), MEDLINE (1946 to July week 2, 2017), and Embase (1980 to 2017, week 30). We also searched prospective clinical trial registers and the reference lists of included studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) investigating the effects of probiotics for prevention or treatment of chemotherapy- or radiotherapy-related diarrhoea in people with cancer.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, extracted data, and assessed risk of bias. We used random-effects models for all meta-analyses. If meta-analysis was not possible, we summarised the results narratively.

MAIN RESULTS

We included 12 studies involving 1554 participants. Eleven studies were prevention studies, of which seven compared probiotics with placebo (887 participants), one compared two doses of probiotics with each other and with placebo (246 participants), and three compared probiotics with another active agent (216 participants).The remaining study assessed the effectiveness of probiotics compared with placebo for treatment of radiotherapy-related diarrhoea (205 participants).For prevention of radiotherapy (with or without chemotherapy)-induced diarrhoea, review authors identified five heterogeneous placebo-controlled studies (with 926 participants analysed). Owing to heterogeneity, we could not carry out a meta-analysis, except for two outcomes. For occurrence of any diarrhoea, risk ratios (RRs) ranged from 0.35 (95% confidence interval (CI) 0.26 to 0.47) to 1.0 (95% CI 0.94 to 1.06) (three studies; low-certainty evidence). A beneficial effect of probiotics on quality of life could neither be demonstrated nor refuted (two studies; low-certainty evidence). For occurrence of grade 2 or higher diarrhoea, the pooled RR was 0.75 (95% CI 0.55 to 1.03; four studies; 420 participants; low-certainty evidence), and for grade 3 or higher diarrhoea, RRs ranged from 0.11 (95% CI 0.06 to 0.23) to 1.24 (95% CI 0.74 to 2.08) (three studies; low-certainty evidence). For probiotic users, time to rescue medication was 36 hours longer in one study (95% CI 34.7 to 37.3), but another study reported no difference (moderate-certainty evidence). For the need for rescue medication, the pooled RR was 0.50 (95% CI 0.15 to 1.66; three studies; 194 participants; very low-certainty evidence). No study reported major differences between groups with respect to adverse effects. Although not mentioned explicitly, no studies reported deaths, except one in which one participant in the probiotics group died of myocardial infarction after three sessions of radiotherapy.Three placebo-controlled studies, with 128 analysed participants, addressed prevention of chemotherapy-induced diarrhoea. For occurrence of any diarrhoea, the pooled RR was 0.59 (95% CI 0.36 to 0.96; two studies; 106 participants; low-certainty evidence). For all other outcomes, a beneficial effect of probiotics could be neither demonstrated nor refuted (one to two studies; 46 to 106 participants; all low-certainty evidence). Studies did not address quality of life nor time to rescue medication.Three studies compared probiotics with another intervention in 213 participants treated with radiotherapy (with or without chemotherapy). One very small study (21 participants) reported less diarrhoea six weeks after treatment when dietary counselling was provided (RR 0.30, 95% CI 0.11 to 0.81; very low-certainty evidence). In another study (148 participants), grade 3 or 4 diarrhoea occurred less often in the probiotics group than in the control group (guar gum containing nutritional supplement) (odds ratio (OR) 0.38, 95% CI 0.16 to 0.89; low-certainty evidence), and two studies (63 participants) found less need for rescue medication of probiotics versus another active treatment (RR 0.44, 95% CI 0.22 to 0.86; very low-certainty evidence). Studies did not address quality of life nor time to rescue medication.One placebo-controlled study with 205 participants addressed treatment for radiotherapy-induced diarrhoea and could not demonstrate or refute a beneficial effect of probiotics on average diarrhoea grade, time to rescue medication for diarrhoea (13 hours longer in the probiotics group; 95% CI -0.9 to 26.9 hours), or need for rescue medication (RR 0.74, 95% CI 0.53 to 1.03; moderate-certainty evidence). This study did not address quality of life.No studies reported serious adverse events or diarrhoea-related deaths.

AUTHORS' CONCLUSIONS

This review presents limited low- or very low-certainty evidence supporting the effects of probiotics for prevention and treatment of diarrhoea related to radiotherapy (with or without chemotherapy) or chemotherapy alone, need for rescue medication, or occurrence of adverse events. All studies were underpowered and heterogeneous. Severe side effects were absent from all studies.Robust evidence on this topic must be provided by future methodologically well-designed trials.

Protective effect of Tongxie Yaofang formula on intestinal tissue of rats with acute radiation enteritis

AIM

To investigate the protective effect of Tongxie Yaofang formula on intestinal tissue of rats with acute radiation enteritis (RE) and to explore the underlying mechanisms.

METHODS

Forty-eight Sprague-Dawley (SD) male rats were randomly divided into four groups: A-D. Group A (n = 12) was given no treatment, while group B (n = 12), group C (n = 12), and group D (n = 12) underwent whole abdominal irradiation at a single dose of 10 Gy. At day 1 after irradiation, group A and group B were given distilled water, while group C were given Tongxie Yaofang formula and group D were given glutamine by gavage for 17 consecutive days. The general condition, defecation, and weight change of rats were daily observed. In each group, jejunal tissue was taken at 6 h after gastric lavage, and the morphology of intestinal tissue was observed under a light microscope. The content of nitric oxide (NO) in jejunal tissue was measured, and the protein contents of interleukin (IL)-6, IL-10, and tumor necrosis factor α (TNF-α) were determined by ELISA.

RESULTS

After gastric lavage, one rat died at day 3, and no death was found in all the other groups. Rats in group C and group D had different degrees of improvement in general condition and mucosanguineous feces. The body weight of rats in group C and group D increased significantly compared with that of group B (P < 0.05). Compared with group B, the contents of NO, IL-6, and TNF-α in group C and group D significantly decreased (P < 0.05). The levels of IL-10 in group C and group D were significantly higher than that in group B (P < 0.01).

CONCLUSION

Tongxie Yaofang formula has a protective effect on intestinal tissue of rats with acute RE possibly via mechanisms that may be related to decreasing the levels of NO, IL-6, and TNF-α in jejunum, increasing the content of IL-10, and reducing the inflammation in intestinal tissue.

Nutritional strategies to prevent gastrointestinal toxicity during pelvic radiotherapy

Radiotherapy-induced damage to non-cancerous gastrointestinal mucosa has effects on secretory and absorptive functions and can interfere with normal gastrointestinal physiology. Nutrient absorption and digestion may be compromised. Dietary manipulation is an attractive option with sound rationale for intervention. The aim of this review was to synthesise published evidence for the use of elemental formulae, low or modified fat diets, fibre, lactose restriction and probiotics, prebiotics and synbiotics to protect the bowel from gastrointestinal side effects during long-course, radical pelvic radiotherapy. Thirty original studies (recruiting n 3197 patients) were identified comprising twenty-four randomised controlled trials, four cohort studies and two comparator trials. Endpoints varied and included symptom scales (Inflammatory Bowel Disease Questionnaire, Common Technology Criteria for Adverse Events, Radiation Therapy Oncology Group) and Bristol Stool Scale. Dietary and supplement interventions were employed with many studies using a combination of interventions. Evidence from RCT was weak for elemental, low or modified fat and low-lactose interventions and modestly positive for the manipulation of fibre during radiotherapy. Evidence for probiotics as prophylactic interventional agents was more promising with a number of trials reporting positive results but strength and strains of interventions vary, as do methodologies and endpoints making it difficult to arrive at firm conclusions with several studies lacking statistical power. This consolidated review concludes that there is insufficient high-grade evidence to recommend nutritional intervention during pelvic radiotherapy. Total replacement of diet with elemental formula could be effective in severe toxicity but this is unproven. Probiotics offer promise but cannot be introduced into clinical practice without rigorous safety analysis, not least in immunocompromised patients.

Therapeutic role of glutamine in management of radiation enteritis: a meta-analysis of 13 randomized controlled trials

Objective

To systematically evaluate the clinical efficacy of glutamine in treating radiation enteritis in cancer patients treated with radiotherapy.

Methods

Electronic databases including Pubmed, Embase, the Cochrane library, and CNKI were systematically searched, until April 2016. Randomized controlled trials (RCT) of glutamine in the treatment of radiation enteritis in cancer patients were searched, and RevMan 5.3 software was used for Meta-analysis.

Results

A total of 13 RCTs were included, involving 979 patients. The results of meta-analysis showed that the total efficacy of glutamine was higher for patients with radiation enteritis compared with that in control group, however, there was no statistically significant difference(OR = 3.07, 95%CI: 0.79-11.96; P > 0.05). The combined ORs for all 5 grades(from grade 0 to grade 4) of radiation enteritis in patients receiving glutamine were 2.06, 1.35, 0.55, 0.62 and 0.59, respectively(P > 0.05 for all). Glutamine also failed to significantly improve the symptoms of radiation enteritis in terms of tenesmus, abdominal cramping and blood in bowel movement(P > 0.05).

Conclusions

Implementation of glutamine fails to improve the severity and symptoms in patients with radiation enteritis.

Interventions to reduce acute and late adverse gastrointestinal effects of pelvic radiotherapy for primary pelvic cancers

BACKGROUND

An increasing number of people survive cancer but a significant proportion have gastrointestinal side effects as a result of radiotherapy (RT), which impairs their quality of life (QoL).

OBJECTIVES

To determine which prophylactic interventions reduce the incidence, severity or both of adverse gastrointestinal effects among adults receiving radiotherapy to treat primary pelvic cancers.

SEARCH METHODS

We conducted searches of CENTRAL, MEDLINE, and Embase in September 2016 and updated them on 2 November 2017. We also searched clinical trial registries.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of interventions to prevent adverse gastrointestinal effects of pelvic radiotherapy among adults receiving radiotherapy to treat primary pelvic cancers, including radiotherapy techniques, other aspects of radiotherapy delivery, pharmacological interventions and non-pharmacological interventions. Studies needed a sample size of 20 or more participants and needed to evaluate gastrointestinal toxicity outcomes. We excluded studies that evaluated dosimetric parameters only. We also excluded trials of interventions to treat acute gastrointestinal symptoms, trials of altered fractionation and dose escalation schedules, and trials of pre- versus postoperative radiotherapy regimens, to restrict the vast scope of the review.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology. We used the random-effects statistical model for all meta-analyses, and the GRADE system to rate the certainty of the evidence.

MAIN RESULTS

We included 92 RCTs involving more than 10,000 men and women undergoing pelvic radiotherapy. Trials involved 44 different interventions, including radiotherapy techniques (11 trials, 4 interventions/comparisons), other aspects of radiotherapy delivery (14 trials, 10 interventions), pharmacological interventions (38 trials, 16 interventions), and non-pharmacological interventions (29 trials, 13 interventions). Most studies (79/92) had design limitations. Thirteen studies had a low risk of bias, 50 studies had an unclear risk of bias and 29 studies had a high risk of bias. Main findings include the following:Radiotherapy techniques: Intensity-modulated radiotherapy (IMRT) versus 3D conformal RT (3DCRT) may reduce acute (risk ratio (RR) 0.48, 95% confidence interval (CI) 0.26 to 0.88; participants = 444; studies = 4; I2 = 77%; low-certainty evidence) and late gastrointestinal (GI) toxicity grade 2+ (RR 0.37, 95% CI 0.21 to 0.65; participants = 332; studies = 2; I2 = 0%; low-certainty evidence). Conformal RT (3DCRT or IMRT) versus conventional RT reduces acute GI toxicity grade 2+ (RR 0.57, 95% CI 0.40 to 0.82; participants = 307; studies = 2; I2 = 0%; high-certainty evidence) and probably leads to less late GI toxicity grade 2+ (RR 0.49, 95% CI 0.22 to 1.09; participants = 517; studies = 3; I2 = 44%; moderate-certainty evidence). When brachytherapy (BT) is used instead of external beam radiotherapy (EBRT) in early endometrial cancer, evidence indicates that it reduces acute GI toxicity (grade 2+) (RR 0.02, 95% CI 0.00 to 0.18; participants = 423; studies = 1; high-certainty evidence).Other aspects of radiotherapy delivery: There is probably little or no difference in acute GI toxicity grade 2+ with reduced radiation dose volume (RR 1.21, 95% CI 0.81 to 1.81; participants = 211; studies = 1; moderate-certainty evidence) and maybe no difference in late GI toxicity grade 2+ (RR 1.02, 95% CI 0.15 to 6.97; participants = 107; studies = 1; low-certainty evidence). Evening delivery of RT may reduce acute GI toxicity (diarrhoea) grade 2+ during RT compared with morning delivery of RT (RR 0.51, 95% CI 0.34 to 0.76; participants = 294; studies = 2; I2 = 0%; low-certainty evidence). There may be no difference in acute (RR 2.22, 95% CI 0.62 to 7.93, participants = 110; studies = 1) and late GI toxicity grade 2+ (RR 0.44, 95% CI 0.12 to 1.65; participants = 81; studies = 1) between a bladder volume preparation of 1080 mls and that of 540 mls (low-certainty evidence). Low-certainty evidence on balloon and hydrogel spacers suggests that these interventions for prostate cancer RT may make little or no difference to GI outcomes.Pharmacological interventions: Evidence for any beneficial effects of aminosalicylates, sucralfate, amifostine, corticosteroid enemas, bile acid sequestrants, famotidine and selenium is of a low or very low certainty. However, evidence on certain aminosalicylates (mesalazine, olsalazine), misoprostol suppositories, oral magnesium oxide and octreotide injections suggests that these agents may worsen GI symptoms, such as diarrhoea or rectal bleeding.Non-pharmacological interventions: Low-certainty evidence suggests that protein supplements (RR 0.23, 95% CI 0.07 to 0.74; participants = 74; studies = 1), dietary counselling (RR 0.04, 95% CI 0.00 to 0.60; participants = 74; studies = 1) and probiotics (RR 0.43, 95% CI 0.22 to 0.82; participants = 923; studies = 5; I2 = 91%) may reduce acute RT-related diarrhoea (grade 2+). Dietary counselling may also reduce diarrhoeal symptoms in the long term (at five years, RR 0.05, 95% CI 0.00 to 0.78; participants = 61; studies = 1). Low-certainty evidence from one study (108 participants) suggests that a high-fibre diet may have a beneficial effect on GI symptoms (mean difference (MD) 6.10, 95% CI 1.71 to 10.49) and quality of life (MD 20.50, 95% CI 9.97 to 31.03) at one year. High-certainty evidence indicates that glutamine supplements do not prevent RT-induced diarrhoea. Evidence on various other non-pharmacological interventions, such as green tea tablets, is lacking.Quality of life was rarely and inconsistently reported across included studies, and the available data were seldom adequate for meta-analysis.

AUTHORS' CONCLUSIONS

Conformal radiotherapy techniques are an improvement on older radiotherapy techniques. IMRT may be better than 3DCRT in terms of GI toxicity, but the evidence to support this is uncertain. There is no high-quality evidence to support the use of any other prophylactic intervention evaluated. However, evidence on some potential interventions shows that they probably have no role to play in reducing RT-related GI toxicity. More RCTs are needed for interventions with limited evidence suggesting potential benefits.

Fiber, prebiotics, and diarrhea: what, why, when and how

PURPOSE OF REVIEW

Dietary fiber and prebiotics have been the focus of research and discussion for decades, but there are still pending concepts and definitions, in particular when addressing their use in the prevention and treatment of diarrhea. The purpose of this review is to present the latest advances in the understanding of dietary fiber and prebiotics, to review their proven role in the management of diarrhea, and to postulate the best timings and optimal doses.

RECENT FINDINGS

The use of prebiotics has encompassed not only prevention but also the treatment of distinct types of diarrhea, at different treatment moments, and with regard to various different markers of outcome. Furthermore, the description of soluble fibers claiming to be prebiotics, and vice versa, has too often been the tone in the literature, which has led to misconceptions in classification and, consequently, confusion over the interpretation of results. It remains difficult to establish a consensus about the real impact of fiber and prebiotics on the prevention and therapy of diarrhea.

SUMMARY

The review highlights the overlapping concepts of fiber and prebiotics, and supports the need for adequate individualization of their use, according to the goal - either prevention or treatment of diarrhea - as well as the optimal timing and dose to be used. Nonetheless, viscous soluble fibers seem to be the best option in treating diarrhea, whereas prebiotics are more important in preventing and avoiding recurrence.

Bowel dysfunction in non-surgical cancer patients

Intestinal dysfunction is common in non-surgical tumor patients, and it manifests as disorder of digestion and absorption, defect of anatomical structure and intestinal barrier dysfunction. Tumor itself and its complications, surgery, and chemoradiotherapy can induce intestinal mucosal ischemia and hypoxia, intestinal smooth muscle degeneration, necrosis and apoptosis, abnormal intestinal motility, disorder of intestinal microflora, and dysfunction of intestinal immune barrier, all of which result in intestinal dysfunction. Tumor syndrome and its complications that can result in intestinal dysfunction include malignant intestinal obstruction, postsurgical gastroparesis syndrome, radiation enteritis, and chemotherapy induced damage to intestinal barrier function, enteric dysbacteriosis, cancerous cachexia, gastrointestinal adverse reactions caused by chemoradiotherapy, somatic symptoms of depression and so on. All of these directly lead to rapid nutritional deficiencies, and interfere with the implementation of antitumor treatment. Management of intestinal dysfunction can improve the efficacy of antitumor treatment and the life quality of patients.