Randomized controlled trial of dietary fiber for the prevention of radiation-induced gastrointestinal toxicity during pelvic radiotherapy

Dietary Counseling Interventions During Radiation Therapy: A Systematic Review of Feasibility, Safety, and Efficacy

Radiotherapy is a common cancer treatment, and concurrent nutritional interventions can maintain nutritional status and improve clinical and supportive care outcomes. However, optimal nutritional interventions during radiotherapy are not firmly established. Herein, we assessed the feasibility, safety, and efficacy of dietary counseling interventions without oral nutrition supplements on health outcomes in adults receiving radiotherapy for cancer in a systematic review. Prospective clinical trials that implemented nutritional counseling interventions during radiotherapy were identified from four databases from inception through December 2023. Feasibility, safety, and efficacy were extracted from 32 articles that described 23 randomized and 4 non-randomized clinical trials. The interventions included individualized nutritional counseling (n = 14 articles), nutritional counseling plus exercise (n = 4), and nutritional counseling focused on increasing or reducing intake of specific nutrients (n = 9). Trials targeted head and neck (n = 12), pelvic cancers (n = 14), and/or breast (n = 5) cancers. Control groups had variable designs and included general nutrition education and intervention as needed. Studies recruited 120 ± 104 participants (range 26-468). Interventions tended to be feasible regarding retention and attendance at sessions, though feasibility metrics varied among different interventions. Most interventions were safe with no studies reporting adverse events attributable to dietary intervention. Individualized dietary counseling interventions tended to lead to between-group differences favoring the intervention group in regard to improved nutritional status, maintenance or attenuation of loss of body mass, improved quality of life, and reduced radiation-induced toxicities. Diets that encouraged/discouraged specific nutrients tended to recruit patients receiving radiation to the pelvic area and resulted in positive or neutral effects on gastrointestinal symptoms. In conclusion, nutritional interventions appear to be feasible, safe, and effective during radiotherapy for various symptom outcomes.

Dietary fibre supplementation enhances radiotherapy tumour control and alleviates intestinal radiation toxicity

BACKGROUND

Non-toxic approaches to enhance radiotherapy outcomes are beneficial, particularly in ageing populations. Based on preclinical findings showing that high-fibre diets sensitised bladder tumours to irradiation by modifying the gut microbiota, along with clinical evidence of prebiotics enhancing anti-cancer immunity, we hypothesised that dietary fibre and its gut microbiota modification can radiosensitise tumours via secretion of metabolites and/or immunomodulation. We investigated the efficacy of high-fibre diets combined with irradiation in immunoproficient C57BL/6 mice bearing bladder cancer flank allografts.

RESULT

Psyllium plus inulin significantly decreased tumour size and delayed tumour growth following irradiation compared to 0.2% cellulose and raised intratumoural CD8+ cells. Post-irradiation, tumour control positively correlated with Lachnospiraceae family abundance. Psyllium plus resistant starch radiosensitised the tumours, positively correlating with Bacteroides genus abundance and increased caecal isoferulic acid levels, associated with a favourable response in terms of tumour control. Psyllium plus inulin mitigated the acute radiation injury caused by 14 Gy. Psyllium plus inulin increased caecal acetate, butyrate and propionate levels, and psyllium alone and psyllium plus resistant starch increased acetate levels. Human gut microbiota profiles at the phylum level were generally more like mouse 0.2% cellulose profiles than high fibre profiles.

CONCLUSION

These supplements may be useful in combination with radiotherapy in patients with pelvic malignancy. Video Abstract.

Intra-abdominal Surgery and Intestinal Syndromes After Pelvic Radiation Therapy

Purpose

To determine the effects of intra-abdominal surgery on the intensities of 5 radiation-induced intestinal syndromes in survivors of pelvic cancer.

Methods and Materials

The analysis included 623 women born in 1927 or later who had survived cancer. They all had received external radiation therapy toward the pelvic area to treat gynecologic cancers. Information from 344 women who did not undergo irradiation, matched for age and residency, was also included. Main outcome measures after the surgical procedures were the intensity scores for 5 radiation-induced intestinal syndromes: urgency-tenesmus syndrome, fecal-leakage syndrome, excessive mucus discharge, excessive gas discharge, and blood discharge. The scores were based on symptom frequencies obtained from patient-reported outcomes and on factor loadings obtained from a previously reported factor analysis. Follow-up was 2 to 15 years after radiation therapy.

Results

Among survivors of cancer, intra-abdominal surgery increased the intensity of the urgency-tenesmus syndrome, the fecal-leakage syndrome, excessive gas discharge, and blood discharge but had a negligible effect on mucus discharge. Intra-abdominal surgery had an especially negative effect on the urgency-tenesmus syndrome. Although the combination of appendectomy with 1 or more other intra-abdominal surgeries resulted in the highest score for all syndromes, appendectomy alone had weak to no effect. In women who did not undergo irradiation, a similar pattern was seen, albeit with much lower scores.

Conclusions

We found intra-abdominal surgery to be a risk factor among survivors of gynecologic cancer, increasing the intensity score of 4 out of 5 radiation-induced intestinal syndromes. During radiation therapy, it may be worthwhile to pay extra attention to the dose of unwanted ionizing radiation to the intestines if the patient previously has undergone intra-abdominal surgery.

The associations between dietary fibers intake and systemic immune and inflammatory biomarkers, a multi-cycle study of NHANES 2015-2020

Background

In recent years, there has been considerable growth in abnormal inflammatory reactions and immune system dysfunction, which are implicated in chronic inflammatory illnesses and a variety of other conditions. Dietary fibers have emerged as potential regulators of the human immune and inflammatory response. Therefore, this study aims to investigate the associations between dietary fibers intake and systemic immune and inflammatory biomarkers.

Methods

This cross-sectional study used data from the National Health and Nutrition Examination Survey (2015-2020). Dietary fibers intake was defined as the mean of two 24-h dietary recall interviews. The systemic immune-inflammation index (SII), systemic inflammation response index (SIRI), neutrophil-to-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), red blood cell distribution width-to-albumin ratio (RA), ferritin, high-sensitivity C-reactive protein (hs-CRP), and white blood cell (WBC) count were measured to evaluate systemic immune and inflammatory states of the body. The statistical software packages R and EmpowerStats were used to examine the associations between dietary fibers intake and systemic immune and inflammatory biomarkers.

Results

Overall, 14,392 participants were included in this study. After adjusting for age, gender, race, family monthly poverty level index, alcohol consumption, smoking status, vigorous recreational activity, body mass index, hyperlipidemia, hypertension, diabetes, and dietary inflammatory index, dietary fibers intake was inversely associated with SII (β = -2.19885, 95% CI: -3.21476 to -1.18294, p = 0.000248), SIRI (β = -0.00642, 95% CI: -0.01021 to -0.00263, p = 0.001738), NLR (β = -0.00803, 95% CI: -0.01179 to -0.00427, p = 0.000284), RA (β = -0.00266, 95% CI: -0.00401 to -0.00131, p = 0.000644), ferritin (β = -0.73086, 95% CI: -1.31385 to -0.14787, p = 0.020716), hs-CRP (β = -0.04629, 95% CI: -0.0743 to -0.01829, p = 0.002119), WBC (β = -0.01624, 95% CI: -0.02685 to -0.00563, p = 0.004066), neutrophils (β = -0.01346, 95% CI: -0.01929 to -0.00764, p = 0.000064). An inverse association between dietary fibers and PLR was observed in the middle (β = -3.11979, 95% CI: -5.74119 to -0.4984, p = 0.028014) and the highest tertile (β = -4.48801, 95% CI: -7.92369 to -1.05234, p = 0.016881) and the trend test (βtrend = -2.2626, 95% CI: -3.9648 to -0.5604, Ptrend = 0.0150). The observed associations between dietary fibers intake and SII, SIRI, NLR, RA, ferritin, hs-CRP, WBC, and neutrophils remained robust and consistent in the sensitivity analysis. No significant interaction by race was found.

Conclusion

Dietary fibers intake is associated with the improvement of the parameters of the immune response and inflammatory biomarkers, supporting recommendations to increase dietary fibers intake for enhanced immune health.

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).

Role of the gut microbiota in anticancer therapy: from molecular mechanisms to clinical applications

In the past period, due to the rapid development of next-generation sequencing technology, accumulating evidence has clarified the complex role of the human microbiota in the development of cancer and the therapeutic response. More importantly, available evidence seems to indicate that modulating the composition of the gut microbiota to improve the efficacy of anti-cancer drugs may be feasible. However, intricate complexities exist, and a deep and comprehensive understanding of how the human microbiota interacts with cancer is critical to realize its full potential in cancer treatment. The purpose of this review is to summarize the initial clues on molecular mechanisms regarding the mutual effects between the gut microbiota and cancer development, and to highlight the relationship between gut microbes and the efficacy of immunotherapy, chemotherapy, radiation therapy and cancer surgery, which may provide insights into the formulation of individualized therapeutic strategies for cancer management. In addition, the current and emerging microbial interventions for cancer therapy as well as their clinical applications are summarized. Although many challenges remain for now, the great importance and full potential of the gut microbiota cannot be overstated for the development of individualized anti-cancer strategies, and it is necessary to explore a holistic approach that incorporates microbial modulation therapy in cancer.

Life style and interaction with microbiota in prostate cancer patients undergoing radiotherapy: study protocol for a randomized controlled trial

Background

Prostate cancer (PCa) is the second most common cancer in men worldwide. The standard non-surgical approach for localized PCa is radiotherapy (RT), but one of the limitations of high-dose RT is the potential increase in gastrointestinal and genitourinary toxicities. We present the protocol of the Microstyle study, a multicentre randomized two-arm crossover clinical trial. The primary outcome will be assessed at the end of 6-month intervention, by measuring the change in adherence to a healthy lifestyle score. The hypothesis is that modifying lifestyle we change microbiome and improve quality of life and decrease side effects of RT.

Methods

Study participants will be recruited among men undergoing RT in two Italian centers (Milan and Naples). We foresee to randomize 300 patients in two intervention arms: Intervention Group (IG) and Control Group (CG). Participants allocated to the IG will meet a dietitian and a physiotherapist before RT to receive personalized diet and exercise recommendations, according to their health status, to improve overall lifestyle and reduce side effects (bowel and/or urinary problems). Dietitian and physiotherapist will work together to set individualized goals to reduce or eliminate side effects and pain according to their health status. All participants (IG) will be given a pedometer device (steps counter) in order to monitor and to spur participants to increase physical activity and reduce sedentary behavior. Participants included in the CG will receive baseline general advice and materials available for patients undergoing RT. According to the cross-over design, the CG will cross to the intervention approach after 6-month, to actively enhance compliance towards suggested lifestyle recommendations for all patients.

Discussion

This trial is innovative in its design because we propose a lifestyle intervention during RT, that includes both dietary and physical activity counselling, as well as monitoring changes in microbiome and serum biomarkers. The promotion of healthy behaviour will be initiated before initiation of standard care, to achieve long lasting effects, controlling side effects, coping with feelings of anxiety and depression and improve efficacy of RT.

Trial registration

ClincalTrial.gov registration number: NCT05155618. Retrospectively registered on December 13, 2021. The first patient was enrolled on October 22, 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09521-4.

Irradiation Induces Tuft Cell Hyperplasia and Myenteric Neuronal Loss in the Absence of Dietary Fiber in a Mouse Model of Pelvic Radiotherapy

Pelvic radiotherapy is associated with chronic intestinal dysfunction. Dietary approaches, such as fiber enrichment during and after pelvic radiotherapy, have been suggested to prevent or reduce dysfunctions. In the present paper, we aimed to investigate whether a diet rich in fermentable fiber could have a positive effect on radiation-induced intestinal damage, especially focusing on tuft cells and enteric neurons. Male C57BL/6 mice were fed either a purified non-fiber diet or the same purified diet with 5% or 15% oat fiber added, starting two weeks prior to sham-irradiation or irradiation with four fractions of 8 Gray. The animals continued on the diets for 1, 6 or 18 weeks, after which the gross morphology of the colorectum was assessed together with the numbers of enteric neurons, tuft cells and crypt-surface units. The results showed that dietary fiber significantly affected the intestinal morphometrics, both in the short and long-term. The presence of dietary fiber stimulated the re-emergence of crypt-surface unit structures after irradiation. At 18 weeks, the animals fed with the non-fiber diet displayed more myenteric neurons than the animals fed with the dietary fibers, but irradiation resulted in a loss of neurons in the non-fiber fed animals. Irradiation, but not diet, affected the tuft cell numbers, and a significant increase in tuft cells was found 6 and 18 weeks after irradiation. In conclusion, dietary fiber intake has the potential to modify neuronal pathogenesis in the colorectum after irradiation. The long-lasting increase in tuft cells induced by irradiation may reflect an as yet unknown role in the mucosal pathophysiology after pelvic irradiation.

Associations between dietary advice on modified fibre and lactose intakes and nutrient intakes in men with prostate cancer undergoing radiotherapy

OBJECTIVES

A variety of non-evidence-based dietary advice on modified fibre and lactose intakes are provided to patients undergoing pelvic radiotherapy to counteract treatment-related bowel symptoms. More knowledge on the nutritional consequences of such advice is needed. This study aimed to explore how advice on modified fibre and lactose intakes during pelvic radiotherapy was associated with nutrient intakes amongst patients with prostate cancer.

METHODS

A total of 77 Swedish men who underwent radiotherapy (50/2 Gy + boost 20-30 Gy) in 2009-2014 due to prostate cancer were given dietary advice at radiotherapy onset (baseline) and at 4 and 8 weeks after radiotherapy onset, to modify their fibre and lactose intakes. At baseline, the participants completed a food frequency questionnaire (FFQ) and a 24-h dietary recall. At 4 and 8 weeks, the participants completed the FFQ and a 4-day estimated food record.Fibre and lactose intakes were measured by intake scores calculated from the FFQs. Multiple linear regression models were used to analyse associations between intake scores and fibre- and lactose-related nutrients.

RESULTS

In adjusted analyses, there were few significant associations between dietary advice on modified fibre and lactose intakes and observed intakes of fibre- and lactose-related nutrients. A more modified lactose intake was thus associated with a lower intake of calcium (P = 0.041), whilst a more modified fibre intake was associated with a higher value for the change in intake of vitamin C (P = 0.016).

CONCLUSIONS

Dietary advice on modified fibre and lactose intake was in most cases not significantly associated with altered nutrient intakes, rather the energy and nutrient intakes were mostly stable during the pelvic radiotherapy. More research is needed on the nutritional consequences of dietary advice on modified fibre and lactose intakes to reach consensus on if they should continue to be provided in the clinic.

A Fiber-Rich Diet and Radiation-Induced Injury in the Murine Intestinal Mucosa

Dietary fiber is considered a strong intestinal protector, but we do not know whether dietary fiber protects against the long-lasting mucosal damage caused by ionizing radiation. To evaluate whether a fiber-rich diet can ameliorate the long-lasting pathophysiological hallmarks of the irradiated mucosa, C57BL/6J mice on a fiber-rich bioprocessed oat bran diet or a fiber-free diet received 32 Gray in four fractions to the distal colorectum using a linear accelerator and continued on the diets for one, six or 18 weeks. We quantified degenerating crypts, crypt fission, cell proliferation, crypt survival, macrophage density and bacterial infiltration. Crypt loss through crypt degeneration only occurred in the irradiated mice. Initially, it was most frequent in the fiber-deprived group but declined to levels similar to the fiber-consuming group by 18 weeks. The fiber-consuming group had a fast response to irradiation, with crypt fission for growth or healing peaking already at one week post-irradiation, while crypt fission in the fiber-deprived group peaked at six weeks. A fiber-rich diet allowed for a more intense crypt cell proliferation, but the recovery of crypts was eventually lost by 18 weeks. Bacterial infiltration was a late phenomenon, evident in the fiber-deprived animals and intensified manyfold after irradiation. Bacterial infiltration also coincided with a specific pro-inflammatory serum cytokine profile. In contrast, mice on a fiber-rich diet were completely protected from irradiation-induced bacterial infiltration and exhibited a similar serum cytokine profile as sham-irradiated mice on a fiber-rich diet. Our findings provide ample evidence that dietary fiber consumption modifies the onset, timing and intensity of radiation-induced pathophysiological processes in the intestinal mucosa. However, we need more knowledge, not least from clinical studies, before this finding can be introduced to a new and refined clinical practice.

A Preparatory Study for a Randomized Controlled Trial of Dietary Fiber Intake During Adult Pelvic Radiotherapy

Background: Patients undergoing pelvic radiotherapy are often advised to omit fiber-rich foods from their diet to reduce the adverse effects of treatment. Scientific evidence supporting this recommendation is lacking, and recent studies on animals and humans have suggested that there is a beneficial effect of dietary fiber for the alleviation of symptoms. Randomized controlled studies on dietary fiber intake during pelvic radiotherapy of sufficient size and duration are needed. As preparation for such a large-scale study, we evaluated the feasibility, compliance, participation rate, and logistics and report our findings here in this preparatory study. Methods: In this preparatory study of a fiber intervention trial, Swedish gynecological cancer patients scheduled for radiotherapy were recruited between January 2019 and August 2020. During the intervention, the participants filled out questionnaires and used an application. They also consumed a fiber supplement at first in powder form, later in capsules. Blood- and fecal samples were collected. The study is registered in clinicaltrials.gov (https://clinicaltrials.gov/ct2/show/NCT04534075?cond=fidura&draw=2&rank=1). Results: Among 136 approached patients, 57 started the study and the participation rate for primary outcomes was 63% (third blood sample) and 65% (third questionnaire). Barely half of the participants provided fecal samples. Providing concise and relevant information to the patients at the right time was crucial in getting them to participate and stay in the study. The most common reasons for declining participation or dropping out were the expected burden of radiotherapy or acute side effects. Tailoring the ambition level to each patient concerning the collection of data beyond the primary endpoints was an important strategy to keep the dropout rate at an acceptable level. Using capsules rather than psyllium in powder form made it much easier to document intake and to create a control group. During the course of the preparatory study, we improved the logistics and for the last 12 participants included, the participation rate was 100% for the earliest primary outcome. Conclusion: A variety of adjustments in this preparatory study resulted in an improved participation rate, which allowed us to set a final protocol and proceed with the main study.

Platelet-derived growth factor C signaling is a potential therapeutic target for radiation proctopathy

Radiation proctopathy (RP) is characterized by inflammation of colorectal tissue and is a common complication of radiation therapy for pelvic malignancies with high incidence but lacking effective treatment. Here, we found that platelet-derived growth factor C (PDGF-C) and fibrosis markers were up-regulated in tissue samples from patients with RP and in rectal tissues after irradiation in a mouse model of RP. Genetic deletion of Pdgf-c in mice ameliorated RP-induced injuries. Genome-wide gene expression profiling and in vitro assays revealed that the promotive effect of PDGF-C in RP development was mediated by activation of PDGF receptors (PDGFRs) and C-X-C motif chemokine receptor 4, a proinflammatory chemokine regulated by transcription factor ETS variant transcription factor 1. Treatment with crenolanib, a selective inhibitor of PDGFRs, prevented or reduced RP in mice after irradiation. These results reveal that inhibition of PDGF-C signaling may have therapeutic value for the treatment of RP.

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.

Exploration of current dietetic practices for patients with gynaecological cancers undergoing radiotherapy in Australia: a cross-sectional survey

PURPOSE

Radiotherapy for gynaecological cancers often causes gastrointestinal (GI) toxicities such as diarrhoea. Evidence for the potential benefits of dietary interventions on the management of acute GI toxicities is inconclusive and of low quality, with no clear evidence-based guidelines to inform clinical practice. This study aims to provide an overview of current opinions and clinical practice of dietitians treating this cohort and to examine existing models of nutrition care in Australian cancer centres.

METHODS

Semi-structured interviews were conducted over a video conferencing service to collect information relating to: demographic characteristics; referral protocol and post-treatment pathways; management strategies and interventions prescribed; and attitudes and confidence in service provided. Descriptive analysis was performed on quantitative data, and thematic analysis was performed on qualitative data.

RESULTS

In total, 17 dietitians across Australia participated in the study. Almost all centres (94%) had dietetics services available for this patient cohort; however, most did not have an automatic referral pathway (94%) or post-treatment pathway (88%). The opinions and prescription of dietary interventions for symptom management had multiple variations of a 'low' or 'modified-fibre' diet with differing ratios of soluble and insoluble fibre. Over half of the respondents believed that practice was not standardized within their workplace (58%) or Australia (82%).

CONCLUSION

There are variations in service provision with respect to opinions and prescription of dietary modifications within dietetic practice across Australia. The present study highlights the need to investigate the efficacy of dietary interventions on symptom management to better inform evidence-based models of care.

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

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

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High fiber diet may improve diarrhea in pelvic cancer patients.

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

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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.

Effects of dietary components on intestinal permeability in health and disease

Altered intestinal permeability plays a role in many pathological conditions. Intestinal permeability is a component of the intestinal barrier. This barrier is a dynamic interface between the body and the food and pathogens that enter the gastrointestinal tract. Therefore, dietary components can directly affect this interface, and many metabolites produced by the host enzymes or the gut microbiota can act as signaling molecules or exert direct effects on this barrier. Our aim was to examine the effects of diet components on the intestinal barrier in health and disease states. Herein, we conducted an in-depth PubMed search based on specific key words (diet, permeability, barrier, health, disease, and disorder), as well as cross references from those articles. The normal intestinal barrier consists of multiple components in the lumen, epithelial cell layer and the lamina propria. Diverse methods are available to measure intestinal permeability. We focus predominantly on human in vivo studies, and the literature is reviewed to identify dietary factors that decrease (e.g., emulsifiers, surfactants, and alcohol) or increase (e.g., fiber, short-chain fatty acids, glutamine, and vitamin D) barrier integrity. Effects of these dietary items in disease states, such as metabolic syndrome, liver disease, or colitis are documented as examples of barrier dysfunction in the multifactorial diseases. Effects of diet on intestinal barrier function are associated with precise mechanisms in some instances; further research of those mechanisms has potential to clarify the role of dietary interventions in treating diverse pathologic states.

Association of Bacteroides acidifaciens relative abundance with high-fibre diet-associated radiosensitisation

BACKGROUND

Patients with pelvic malignancies often receive radiosensitising chemotherapy with radiotherapy to improve survival; however, this is at the expense of increased normal tissue toxicity, particularly in elderly patients. Here, we explore if an alternative, low-cost, and non-toxic approach can achieve radiosensitisation in mice transplanted with human bladder cancer cells. Other investigators have shown slower growth of transplanted tumours in mice fed high-fibre diets. We hypothesised that mice fed a high-fibre diet would have improved tumour control following ionising radiation (IR) and that this would be mediated through the gut microbiota.

RESULTS

We investigated the effects of four different diets (low-fibre, soluble high-fibre, insoluble high-fibre, and mixed soluble/insoluble high-fibre diets) on tumour growth in immunodeficient mice implanted with human bladder cancer flank xenografts and treated with ionising radiation, simultaneously investigating the composition of their gut microbiomes by 16S rRNA sequencing. A significantly higher relative abundance of Bacteroides acidifaciens was seen in the gut (faecal) microbiome of the soluble high-fibre group, and the soluble high-fibre diet resulted in delayed tumour growth after irradiation compared to the other groups. Within the soluble high-fibre group, responders to irradiation had significantly higher abundance of B. acidifaciens than non-responders. When all mice fed with different diets were pooled, an association was found between the survival time of mice and relative abundance of B. acidifaciens. The gut microbiome in responders was predicted to be enriched for carbohydrate metabolism pathways, and in vitro experiments on the transplanted human bladder cancer cell line suggested a role for microbial-generated short-chain fatty acids and/or other metabolites in the enhanced radiosensitivity of the tumour cells.

CONCLUSIONS

Soluble high-fibre diets sensitised tumour xenografts to irradiation, and this phenotype was associated with modification of the microbiome and positively correlated with B. acidifaciens abundance. Our findings might be exploitable for improving radiotherapy response in human patients.

Is Host Metabolism the Missing Link to Improving Cancer Outcomes?

For the past 100 years, oncologists have relentlessly pursued the destruction of tumor cells by surgical, chemotherapeutic or radiation oncological means. Consistent with this focus, treatment plans are typically based on key characteristics of the tumor itself such as disease site, histology and staging based on local, regional and systemic dissemination. Precision medicine is similarly built on the premise that detailed knowledge of molecular alterations of tumor cells themselves enables better and more effective tumor cell destruction. Recently, host factors within the tumor microenvironment including the vasculature and immune systems have been recognized as modifiers of disease progression and are being targeted for therapeutic gain. In this review, we argue that—to optimize the impact of old and new treatment options—we need to take account of an epidemic that occurs independently of—but has major impact on—the development and treatment of malignant diseases. This is the rapidly increasing number of patients with excess weight and its’ attendant metabolic consequences, commonly described as metabolic syndrome. It is well established that patients with altered metabolism manifesting as obesity, metabolic syndrome and chronic inflammation have an increased incidence of cancer. Here, we focus on evidence that these patients also respond differently to cancer therapy including radiation and provide a perspective how exercise, diet or pharmacological agents may be harnessed to improve therapeutic responses in this patient population.

Impact of the antifermentative diet during radiotherapy for prostate cancer in elderly, SÃO Paulo, Brazil

OBJECTIVE

Assess the impact of the antifermentative diet on the dietary intake and body composition of elderly prostate cancer patients in radiotherapy.

METHODS

Observational and prospective study involving 45 men aged 60 years or older, receiving radiotherapy for prostate cancer treatment. The dietary intake was assessed at four times during radiotherapy: onset (T_Pre), between the 11th and 16th day (T₁), between the 24th and 28th day (T₂), and on the last day (T_Last). The body composition was assessed before and on the last day of radiotherapy, by means of the body weight and height, mid-arm circumference, triceps and subscapular skin folds, phase angle, resistance, and reactance. The data were statistically treated, considering a 5% significance level.

RESULTS

The intake of energy, dietary fibers, and some nutrients decreased during the radiotherapy (p < 0.05). The intake of vitamins E, B1, B2, and folate, of the minerals calcium, magnesium, potassium, sodium, and phosphorus, and of the amino acid leucine dropped when the four assessment times were compared (p < 0.05). As regards the body composition, an impact was observed at the end of the radiotherapy, with lower body weight, arm circumference, subscapular cutaneous fold, phase angle and reactance (p < 0.05).

CONCLUSION

The antifermentative diet negatively influenced the food consumption and body composition of elderly patients submitted to radiotherapy for prostate cancer.

Effects of a nutrition intervention on acute and late bowel symptoms and health-related quality of life up to 24 months post radiotherapy in patients with prostate cancer: a multicentre randomised controlled trial

Purpose

Radiotherapy to the prostate gland and pelvic lymph nodes may cause acute and late bowel symptoms and diminish quality of life. The aim was to study the effects of a nutrition intervention on bowel symptoms and health-related quality of life, compared with standard care.

Methods

Patients were randomised to a nutrition intervention (n = 92) aiming to replace insoluble fibres with soluble and reduce intake of lactose, or a standard care group (n = 88) who were recommended to maintain their habitual diet. Bowel symptoms, health-related quality of life and intake of fibre and lactose-containing foods were assessed up to 24 months after radiotherapy completion. Multiple linear regression was used to analyse the effects of the nutrition intervention on bowel symptoms during the acute (up to 2 months post radiotherapy) and the late (7 to 24 months post radiotherapy) phase.

Results

Most symptoms and functioning worsened during the acute phase, and improved during the late phase in both the intervention and standard care groups. The nutrition intervention was associated with less blood in stools (p = 0.047), flatulence (p = 0.014) and increased loss of appetite (p = 0.018) during the acute phase, and more bloated abdomen in the late phase (p = 0.029). However, these associations were clinically trivial or small.

Conclusions

The effect of the nutrition intervention related to dietary fibre and lactose on bowel symptoms from pelvic RT was small and inconclusive, although some minor and transient improvements were observed. The results do not support routine nutrition intervention of this type to reduce adverse effects from pelvic radiotherapy.

Electronic supplementary material

The online version of this article (10.1007/s00520-019-05182-5) contains supplementary material, which is available to authorized users.

Intake of citrus fruits and vegetables and the intensity of defecation urgency syndrome among gynecological cancer survivors

Background

Despite the experimental evidence that certain dietary compounds lower the risk of radiation-induced damage to the intestine, clinical data are missing and dietary advice to irradiated patients is not evidence-based.

Materials and methods

We have previously identified 28 intestinal health-related symptoms among 623 gynaecological-cancer survivors (three to fifteen years after radiotherapy) and 344 matched population-based controls. The 28 symptoms were grouped into five radiation-induced survivorship syndromes: defecation-urgency syndrome, fecal-leakage syndrome, excessive mucus discharge, excessive gas discharge and blood discharge. The grouping was based on factor scores produced by Exploratory Factor Analysis in combination with the Variable Cutoff Method. Frequency of food intake was measured by a questionnaire. We evaluated the relationship between dietary intake and the intensity of the five syndromes.

Results

With the exception of excessive mucus discharge, the intensity of all syndromes declined with increasing intake of citrus fruits. The intensity of defecation-urgency and fecal-leakage syndrome declined with combined intake of vegetables and citrus fruits. The intensity of excessive mucus discharge was increased with increasing intake of gluten.

Conclusion

In this observational study, we found an association between a high intake of citrus fruits and vegetables and a lower intensity of the studied radiation-induced cancer survivorship syndromes. Our data suggest it may be worthwhile to continue to search for a role of the diet before, during and after radiotherapy to help the cancer survivor restore her or his intestinal health after irradiation.

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.

Psychosocial Support in Cancer Cachexia Syndrome: The Evidence for Supported Self-Management of Eating Problems during Radiotherapy or Chemotherapy Treatment

People receiving cancer treatment are at nutritional risk. Their eating problems can lead to malnutrition and weight loss. Involuntary weight loss is also a defining characteristic of tumor-induced cachexia. Weight loss is associated with poor tolerance of treatment, poor treatment outcomes, morbidity, and mortality. Support for self-management of nutritional risk may protect against malnutrition and be important in multimodal therapies to arrest the progression of cachexia. Nurses can help patients by supporting self-management of eating problems. This scoping review is about eating problems during cancer treatment. It considers patient experience and self-management of eating problems during cancer treatment for the proactive management of malnutrition and cachexia. It draws on a systematic search of Medline, CINAHL, PsycINFO, and the Cochrane Library for publications about people with cancer who have eating problems during treatment. Limits were English language; January 2000 to December 2017; adults. The search found studies about eating problems in patients treated with chemotherapy or radiotherapy for head-and-neck cancer, lung cancer, gastrointestinal cancer, breast cancer, testicular cancer, and ovarian cancer. Nutritional counseling can improve nutritional intake, quality of life, and weight. However, the patient perspective on self-management and how to motivate engagement in nutritional care is unexplored. There is a potential for reducing nutritional risk during cancer treatment using psychoeducation to support behavioral change, thus empower self-management of eating problems. Benefits are likely in subgroups of people receiving cancer treatment, such as those with head and neck, gastrointestinal, and lung cancers.