Prophylactic probiotics for cancer therapy-induced diarrhoea: a meta-analysis

An unmet need for pharmacology: Treatments for radiation-induced gastrointestinal mucositis

Gastrointestinal mucositis (GIM) continues to be a significant issue in the management of abdominal cancer radiation treatments and chemotherapy, causing significant patient discomfort and therapy interruption or even cessation. This review will first focus on radiotherapy induced GIM, providing an understanding of its clinical landscape. Subsequently, the aetiology of GIM will be reviewed, highlighting diverse contributing factors. The cellular and tissue damage and associated molecular responses in GIM will be summarised in the context of the underlying complex biological processes. Finally, available drugs and pharmaceutical therapies will be evaluated, underscoring their insufficiency, and highlighting the need for further research and innovation. This review will emphasize the urgent need for improved pharmacologic therapeutics for GIM, which is a key research priority in oncology.

Role of mucositis in predicting gut microbiota composition in people with cancer

PURPOSE OF REVIEW

Disruption of the precious ecosystem of micro-organisms that reside in the gut - the gut microbiota - is rapidly emerging as a key driver of the adverse side effects/toxicities caused by numerous anti-cancer agents. Although the contribution of the gut microbiota to these toxicities is understood with ever increasing precision, the cause of microbial disruption (dysbiosis) remains poorly understood. Here, we discuss current evidence on the cause(s) of dysbiosis after cancer therapy, positioning breakdown of the intestinal mucosa (mucositis) as a central cause.

RECENT FINDINGS

Dysbiosis in people with cancer has historically been attributed to extensive antibiotic use. However, evidence now suggests that certain antibiotics have minimal impacts on the microbiota. Indeed, recent evidence shows that the type of cancer therapy predicts microbiota composition independently of antibiotics. Given most anti-cancer drugs have modest effects on microbes directly, this suggests that their impact on the gut microenvironment, in particular the mucosa, which is highly vulnerable to cytotoxicity, is a likely cause of dysbiosis. Here, we outline evidence that support this hypothesis, and discuss the associated clinical implications/opportunities.

SUMMARY

The concept that mucositis dictates microbiota compositions provides two important implications for clinical practice. Firstly, it reiterates the importance of prioritising the development of novel mucoprotectants that preserve mucosal integrity, and indirectly support microbial stability. Secondly, it provides an opportunity to identify dysbiotic events and associated consequences using readily accessible, minimally invasive biomarkers of mucositis such as plasma citrulline.

Microbiome in Cancer Development and Treatment

Targeting the microbiome, microbiota-derived metabolites, and related pathways represents a significant challenge in oncology. Microbiome analyses have confirmed the negative impact of cancer treatment on gut homeostasis, resulting in acute dysbiosis and severe complications, including massive inflammatory immune response, mucosal barrier disruption, and bacterial translocation across the gut epithelium. Moreover, recent studies revealed the relationship between an imbalance in the gut microbiome and treatment-related toxicity. In this review, we provide current insights into the role of the microbiome in tumor development and the impact of gut and tumor microbiomes on chemo- and immunotherapy efficacy, as well as treatment-induced late effects, including cognitive impairment and cardiotoxicity. As discussed, microbiota modulation via probiotic supplementation and fecal microbiota transplantation represents a new trend in cancer patient care, aiming to increase bacterial diversity, alleviate acute and long-term treatment-induced toxicity, and improve the response to various treatment modalities. However, a more detailed understanding of the complex relationship between the microbiome and host can significantly contribute to integrating a microbiome-based approach into clinical practice. Determination of causal correlations might lead to the identification of clinically relevant diagnostic and prognostic microbial biomarkers. Notably, restoration of intestinal homeostasis could contribute to optimizing treatment efficacy and improving cancer patient outcomes.

Exercise and the gut microbiome: implications for supportive care in cancer

PURPOSE

Growing recognition of the gut microbiome as an influential modulator of cancer treatment efficacy and toxicity has led to the emergence of clinical interventions targeting the microbiome to enhance cancer and health outcomes. The highly modifiable nature of microbiota to endogenous, exogenous, and environmental inputs enables interventions to promote resilience of the gut microbiome that have rapid effects on host health, or response to cancer treatment. While diet, probiotics, and faecal microbiota transplant are primary avenues of therapy focused on restoring or protecting gut function in people undergoing cancer treatment, the role of physical activity and exercise has scarcely been examined in this population.

METHODS

A narrative review was conducted to explore the nexus between cancer care and the gut microbiome in the context of physical activity and exercise as a widely available and clinically effective supportive care strategy used by cancer survivors.

RESULTS

Exercise can facilitate a more diverse gut microbiome and functional metabolome in humans; however, most physical activity and exercise studies have been conducted in healthy or athletic populations, primarily using aerobic exercise modalities. A scarcity of exercise and microbiome studies in cancer exists.

CONCLUSIONS

Exercise remains an attractive avenue to promote microbiome health in cancer survivors. Future research should elucidate the various influences of exercise modalities, intensities, frequencies, durations, and volumes to explore dose-response relationships between exercise and the gut microbiome among cancer survivors, as well as multifaceted approaches (such as diet and probiotics), and examine the influences of exercise on the gut microbiome and associated symptom burden prior to, during, and following cancer treatment.

Effect of probiotic supplementation on chemotherapy- and radiotherapy-related diarrhoea in patients with cancer: an umbrella review of systematic reviews and meta-analyses

To date, several systematic reviews and meta-analyses (SRMA) have investigated the effects of probiotics, but the certainty of the evidence for an effect on chemotherapy and radiotherapy-related diarrhoea has not been assessed. We conducted an overview of SRMA, searching MEDLINE, Scopus, and ISI Web of Science from inception up to February 2022. We summarised the findings of eligible SRMA. Subsequently, we included randomised clinical trials (RCT) from the SRMA in meta-analyses, using a quality effects model to calculate the OR and 95 % CI for each outcome. We used ‘A Measurement Tool to Assess Systematic Reviews’ and the Cochrane risk of bias tool to assess the methodological quality of the SRMA and their RCT, respectively. We used the ‘Grading of Recommendations Assessment, Development, and Evaluation’.We included thirteen SRMA, which reported pooled effect sizes for chemotherapy and radiotherapy-related diarrhoea based on a total of eighteen RCT. Our meta-analyses demonstrated statistically significant beneficial effects from probiotics on all outcomes, except stool consistency; diarrhoea (any grade) OR 0·35 (95 % CI 0·22, 0·54), grade ≥ 2 diarrhoea 0·43 (0·25, 0·74), grade ≥ 3 diarrhoea 0·30 (0·15, 0·59), use of medication 0·49 (0·27, 0·88), soft stool 1·10 (0·44, 2·76) and watery stool 0·52 (0·29, 1·29). Probiotics use can reduce the incidence of diarrhoea in cancer patients in chemotherapy and radiotherapy, but the certainty of evidence for significant outcomes was very low and low.

The effects of synbiotics supplementation on reducing chemotherapy-induced side effects in women with breast cancer: a randomized placebo-controlled double-blind clinical trial

BACKGROUND

The prevalence of breast cancer and its mortality rate are increasing rapidly among women worldwide. On other hand, the courses of chemotherapy as the main treatment for these patients are too much exhaustive and annoying. This study was designed to evaluate the use of synbiotics (probiotics + prebiotics) supplementation as a safe and inexpensive adjuvant treatment in reducing common chemotherapy side effects in women with breast cancer.

METHODS

The current study was conducted on 67 women with definitive diagnosis of breast cancer who were hospitalized to receive one-day chemotherapy sessions, and met the inclusion criteria. The patients were randomly allocated to the intervention or control group to receive synbiotics or placebo, respectively. They received oral consumption of synbiotics supplements twice a day for 8 weeks. The primary outcome was the changes in severity or experience of chemotherapy complication, analyzed by intention to treat (ITT). The instruments included 7 validated questionnaires which were used to assess chemotherapy complications in the initiation, 4 weeks and 8 weeks after intervention. Dietary intake was measured by 24-h dietary recall at the beginning, week 4 and week 8. Data were analyzed by SPSS software version 24. P-value < 0.05 was considered as statistically significant.

RESULTS

67 breast cancer patients participated in the study. 8 weeks after intervention and adjusting the confounders, the severity of chemotherapy complications including unnormal defecation (P = 0.005) and fatigue (P < 0/001) decreased significantly in the synbiotics group compared to the placebo group. Furthermore, nausea/vomiting (P = 0.015), and anorexia (P < 0.001) were decreased at the end of the study compared to the first visit, but it was not statistically significant compared to the placebo group.

CONCLUSIONS

Synbiotics supplementation during chemotherapy can potentially reduce the severity of fatigue and abnormal defecation. It can help reduce anorexia and nausea/vomiting.

TRIAL REGISTRATION

This study was registered in the Iranian Registry of Clinical Trials (IRCT) (registered code: IRCT20091114002709N56) (date of registration: 5/5/2021). Direct link to the trial page: https://www.irct.ir/trial/54559 .

Randomized double-blind, placebo-controlled multicenter phase III study of prevention of irinotecan-induced diarrhea by a probiotic mixture containing Bifidobacterium BB-12®Lactobacillus rhamnosus LGG® in colorectal cancer patients

Background

The incidence of irinotecan-induced diarrhea varies between 60-90%, by which the incidence of severe diarrhea is 20-40%. The objective of this phase III trial was to determine the effectiveness of the probiotic mixture containing Bifidobacterium, BB-12® and Lactobacillus rhamnosus, LGG® in the prophylaxis of irinotecan-induced diarrhea in metastatic colorectal cancer patients due to a reduction in the activity of intestinal beta-D-glucuronidase.

Methods

From March 2016 to May 2022, a total of 242 patients with colorectal cancer starting a new line of irinotecan-based therapy were registered to the study in 11 cancer centers in Slovakia. Patients were randomized in a ratio 1:1 to probiotic formula vs. placebo that was administered for 6 weeks. Each capsule of Probio-Tec® BG-Vcap-6.5 contained 2.7x109 colony-forming units (CFU) of 2 lyophilized probiotic strains Bifidobacterium, BB-12® (50%) and Lactobacillus rhamnosus GG, LGG® (50%).

Results

Administration of probiotics compared to placebo was not associated with a significant reduction of grade 3/4 diarrhea (placebo arm 11.8% vs. probiotic arm 7.9%, p=0.38). Neither the overall incidence of diarrhea (46.2% vs. 41.2%, p=0.51) nor the incidence of enterocolitis (3.4% vs. 0.9%, p=0.37) was different in the placebo vs. probiotic arm. Subgroup analysis revealed that patients with colostomy had higher incidence of any diarrhea and grade 3/4 diarrhea in the placebo arm compared to the probiotic arm (48.5% vs. 22.2%, p=0.06 and 15.2% vs. 0%, p=0.06, respectively). Moreover, patients on probiotic arm had significantly better diarrhea-free survival (HR = 0.41, 95%CI 0.18 - 0.95, p=0.05) and needed less loperamide (p=0.01) compared to patients on placebo arm. We did not observe any infection caused by probiotic strains used in this study.

Conclusion

This study failed to achieve its primary endpoint, and results suggest a lack of benefit of administered probiotic formula for the prevention of irinotecan-induced diarrhea. However, subgroup analysis suggests a possible benefit in patients with colostomy.

Synbiotics as Supplemental Therapy for the Alleviation of Chemotherapy-Associated Symptoms in Patients with Solid Tumours

Chemotherapy is still the first line of treatment for most cancer patients. Patients receiving chemotherapy are generally prone to infections, which result in complications, such as sepsis, mucositis, colitis, and diarrhoea. Several nutritional approaches have been trialled to counter the chemotherapy-associated side effects in cancer patients, but none have yet been approved for routine clinical use. One of the approaches to reduce or avoid chemotherapy-associated complications is to restore the gut microbiota. Gut microbiota is essential for the healthy functioning of the immune system, metabolism, and the regulation of other molecular responses in the body. Chemotherapy erodes the mucosal layer of the gastrointestinal tract and results in the loss of gut microbiota. One of the ways to restore the gut microbiota is through the use of probiotics. Probiotics are the ‘good’ bacteria that may provide health benefits if consumed in appropriate amounts. Some studies have highlighted that the consumption of probiotics in combination with prebiotics, known as synbiotics, may provide better health benefits when compared to probiotics alone. This review discusses the different nutritional approaches that have been studied in an attempt to combat chemotherapy-associated side effects in cancer patients with a particular focus on the use of pre-, pro- and synbiotics.

Chemotherapy: how to reduce its adverse effects while maintaining the potency?

Chemotherapy is one of the widely used anticancer treatments that involves the use of powerful cytotoxic drugs to stop tumor growth by targeting rapidly dividing cells through various mechanisms, which will be elucidated in this review. Introduced during the early twentieth century, chemotherapy has since lengthened the longevity of innumerable cancer patients. However, the increase in lifespan is at the expense of quality of life as patients are at risk of developing short-term and long-term side effects following chemotherapy, such as alopecia (hair loss), chemotherapy-induced peripheral neuropathy, chemotherapy-induced nausea and vomiting, cardiotoxicity, diarrhea, infertility, and chemo brain. Currently, a number of these chemotherapy-induced adverse effects are managed through supportive care and approved treatments, while the rest of the side effects are unavoidable. Hence, chemotherapeutic drugs associated with inevitable side effects are only administered when their therapeutic role outweighs their chemotoxicity, thus severely limiting the potency of chemotherapy in treating malignancy. Therein, the potential approaches to alleviating side effects of chemotherapy ranging from pharmaceutical drugs to alternative therapies will be discussed in this review in hopes of increasing the tolerance and effectiveness of future chemotherapeutic treatments.

Gut microbiota: A novel and potential target for radioimmunotherapy in colorectal cancer

Colorectal cancer (CRC) is one of the most common cancers, with a high mortality rate, and is a major burden on human health worldwide. Gut microbiota regulate human immunity and metabolism through producing numerous metabolites, which act as signaling molecules and substrates for metabolic reactions in various biological processes. The importance of host-gut microbiota interactions in immunometabolic mechanisms in CRC is increasingly recognized, and interest in modulating the microbiota to improve patient's response to therapy has been raising. However, the specific mechanisms by which gut microbiota interact with immunotherapy and radiotherapy remain incongruent. Here we review recent advances and discuss the feasibility of gut microbiota as a regulatory target to enhance the immunogenicity of CRC, improve the radiosensitivity of colorectal tumor cells and ameliorate complications such as radiotoxicity. Currently, great breakthroughs in the treatment of non-small cell lung cancer and others have been achieved by radioimmunotherapy, but radioimmunotherapy alone has not been effective in CRC patients. By summarizing the recent preclinical and clinical evidence and considering regulatory roles played by microflora in the gut, such as anti-tumor immunity, we discuss the potential of targeting gut microbiota to enhance the efficacy of radioimmunotherapy in CRC and expect this review can provide references and fresh ideas for the clinical application of this novel strategy.

Differences in the Intestinal Microbiome Associated with Diarrhea during Lenvatinib Treatment for Hepatocellular Carcinoma

INTRODUCTION

Lenvatinib has been widely used for the treatment of advanced hepatocellular carcinoma (HCC). Some adverse events, including diarrhea, have been reported for lenvatinib. Diarrhea may be associated with the changes in the intestinal microbiome; however, the underlying mechanism has not been elucidated.

AIM

In this study, we aimed to investigate the relationship between the intestinal microbiome and diarrhea caused by lenvatinib via analysis of fecal samples collected before treatment.

METHODS

A total of 21 patients with advanced HCC who were treated with lenvatinib were enrolled. Fecal samples were collected from patients. The patients were divided into diarrhea (n = 8) and nondiarrhea groups (n = 12). We compared the characteristics of patients, incidence of adverse events, composition of the intestinal microbiome, and enrichment of functional pathways between both groups using QIIME2 and PICRUSt2.

RESULTS

The median age of the two groups was 73 years. The nondiarrhea group comprised a relatively higher number of male patients than the diarrhea group; however, there were no significant differences in patient characteristics between both groups. The proportion of the microbiome was similar, and alpha and beta diversities were not significantly different between both groups. The relative abundance of order Bacteroidales, including Parabacteroides and Prevotella, was higher in the diarrhea group than in the nondiarrhea group. PICRUSt2 analysis showed some metabolic pathways, including butanoate (butyrate) metabolism, were enriched in the nondiarrhea group when compared with those in the diarrhea group.

CONCLUSION

Differences in the intestinal microbiomes and their functions may influence the incidence of diarrhea during lenvatinib treatment.

Gut microbiota in acute leukemia: Current evidence and future directions

Gut microbiota includes a large number of microorganisms inhabiting the human gastrointestinal tract, which show a wide range of physiological functions, including digestion, metabolism, immunity, neural development, etc., and are considered to play an increasingly important role in health and disease. A large number of studies have shown that gut microbiota are closely associated with the onset and development of several diseases. In particular, the interaction between gut microbiota and cancer has recently attracted scholars' attention. Acute leukemia (AL) is a common hematologic malignancy, especially in children. Microbiota can affect hematopoietic function, and the effects of chemotherapy and immunotherapy on AL are noteworthy. The composition and diversity of gut microbiota are important factors that influence and predict the complications and prognosis of AL after chemotherapy or hematopoietic stem cell transplantation. Probiotics, prebiotics, fecal microbiota transplantation, and dietary regulation may reduce side effects of leukemia therapy, improve response to treatment, and improve prognosis. This review concentrated on the role of the gut microbiota in the onset and development of AL, the response and side effects of chemotherapy drugs, infection during treatment, and therapeutic efficacy. According to the characteristics of gut microbes, the applications and prospects of microbial preparations were discussed.

A Gut Instinct on Leukaemia: A New Mechanistic Hypothesis for Microbiota-Immune Crosstalk in Disease Progression and Relapse

Despite significant advances in the treatment of Chronic Myeloid and Acute Lymphoblastic Leukaemia (CML and ALL, respectively), disease progression and relapse remain a major problem. Growing evidence indicates the loss of immune surveillance of residual leukaemic cells as one of the main contributors to disease recurrence and relapse. More recently, there was an appreciation for how the host’s gut microbiota predisposes to relapse given its potent immunomodulatory capacity. This is especially compelling in haematological malignancies where changes in the gut microbiota have been identified after treatment, persisting in some patients for years after the completion of treatment. In this hypothesis-generating review, we discuss the interaction between the gut microbiota and treatment responses, and its capacity to influence the risk of relapse in both CML and ALL We hypothesize that the gut microbiota contributes to the creation of an immunosuppressive microenvironment, which promotes tumour progression and relapse.

Gut microbiota-drug interactions in cancer pharmacotherapies: implications for efficacy and adverse effects

INTRODUCTION

The gut microbiota is involved in host physiology and health. Reciprocal microbiota-drug interactions are increasingly recognized as underlying some individual differences in therapy response and adverse events. Cancer pharmacotherapies are characterized by a high degree of interpatient variability in efficacy and side effect profile and recently, the microbiota has emerged as a factor that may underlie these differences.

AREAS COVERED

The effects of cancer pharmacotherapy on microbiota composition and function are reviewed with consideration of the relationship between baseline microbiota composition, microbiota modification, antibiotics exposure and cancer therapy efficacy. We assess the evidence implicating the microbiota in cancer therapy-related adverse events including impaired gut function, cognition and pain perception. Finally, potential mechanisms underlying microbiota-cancer drug interactions are described, including direct microbial metabolism, and microbial modulation of liver metabolism and immune function. This review focused on preclinical and clinical studies conducted in the last 5 years.

EXPERT OPINION

Preclinical and clinical research supports a role for baseline microbiota in cancer therapy efficacy, with emerging evidence that the microbiota modification may assist in side effect management. Future efforts should focus on exploiting this knowledge towards the development of microbiota-targeted therapies. Finally, a focus on specific drug-microbiota-cancer interactions is warranted.

Selenium-enriched Bifidobacterium longum DD98 attenuates irinotecan-induced intestinal and hepatic toxicity in vitro and in vivo

Irinotecan (CPT-11) is a camptothecin chemotherapy drug largely used in treating cancers. However, its strong adverse effects, such as gastrointestinal and hepatic toxicities, tend to reduce the patients' life qualities and to limit the clinical use of CPT-11. The protective roles of selenium (Se) and probiotics against CPT-11-induced toxicity have been widely reported. However, the application of Se-enriched probiotics in the adjuvant therapy of CPT-11 has not been well explored. The purpose of this study is to evaluate the in-vitro and in-vivo effects of Se-enriched Bifidobacterium longum DD98 (Se-B. longum DD98) as a chemotherapy preventive agent on alleviating intestinal and hepatic toxicities induced by CPT-11 chemotherapy. The results showed that Se-B. longum DD98 positively regulated the aberrant cell viability and oxidative stress induced by CPT-11 both in human normal liver (L-02) and rat small intestinal epithelial (IEC-6) cell lines. In vivo experiment revealed that Se-B. longum DD98 significantly attenuated intestinal and hepatic toxicities by ameliorating symptoms such as body weight loss and diarrhea, and by improving the biochemical indicators of hepatotoxicity and oxidative stress. Furthermore, we discovered that the protective effects of Se-B. longum DD98 based largely upon decreasing the pro-inflammatory cytokines IL-1β and IL-18 and enhancing the expression of tight-junction proteins occludin and ZO-1, as well as restoring the composition and diversity of gut microbiota. Results suggested that Se-B. longum DD98 effectively protected livers and intestines against the CPT-11-induced damages, and therefore, could be considered as a promising adjuvant therapeutic agent with CPT-11 for the cancer treatment.

Does Chemotherapy-Induced Gastrointestinal Mucositis Affect the Bioavailability and Efficacy of Anti-Infective Drugs?

Antimicrobial prophylaxis is increasingly being used in patients with hematological malignancies receiving high-dose chemotherapy and hematopoietic stem cell transplantation (HSCT). However, few studies have focused on the potential impact of gastrointestinal mucositis (GI-M), a frequently observed side effect of chemotherapy in patients with cancer that affects the gastrointestinal microenvironment, on drug absorption. In this review, we discuss how chemotherapy leads to an overall loss of mucosal surface area and consequently to uncontrolled transport across the barrier. The barrier function is depending on intestinal luminal pH, intestinal motility, and diet. Another factor contributing to drug absorption is the gut microbiota, as it modulates the bioavailability of orally administrated drugs by altering the gastrointestinal properties. To better understand the complex interplay of factors in GI-M and drug absorption we suggest: (i) the longitudinal characterization of the impact of GI-M severity on drug exposure in patients, (ii) the development of tools to predict drug absorption, and (iii) strategies that allow the support of the gut microbiota. These studies will provide relevant data to better design strategies to reduce the severity and impact of GI-M in patients with cancer.

The impact of pelvic radiotherapy on the gut microbiome and its role in radiation-induced diarrhoea: a systematic review

Pelvic radiotherapy is the key treatment for pelvic malignancies, usually including pelvic primary tumour lesions and lymphatic drainage areas in the pelvic region. Therefore, the intestinal tract in the radiation field is inevitably damaged, a phenomenon clinically referred to as radiation enteritis, and diarrhoea is the most common clinical symptom of radiation enteritis. Therefore, it is necessary to study the mechanism of radiation-induced diarrhoea. It has been found that the gut microbiome plays an important role in the development of diarrhoea in response to pelvic radiotherapy, and the species and distribution of intestinal microbiota are significantly altered in patients after pelvic radiotherapy. In this study, we searched for articles indexed in the Cochrane Library, Web of Science, EMBASE and PubMed databases in English and CNKI, Wanfang data and SINOMED in Chinese from their inception dates through 13 March 2020 to collect studies on the gut microbiome in pelvic radiotherapy patients. Eventually, we included eight studies: one study report on prostatic carcinoma, five studies on gynaecological carcinoma and two papers on pelvic carcinomas. All studies were designed as self-controlled studies, except for one that compared toxicity to nontoxicity. The results from all the studies showed that the diversity of intestinal flora decreased during and after pelvic radiotherapy, and the diversity of intestinal flora decreased significantly in patients with diarrhoea after radiotherapy. Five studies observed that the community composition of the gut microbiota changed at the phylum, order or genus level before, during, and after pelvic radiotherapy at different time points. In addition, the composition of the gut microbiota before radiotherapy was different between patients with postradiotherapy diarrhoea and those without diarrhoea in five studies. However, relevant studies have not reached consistent results regarding the changes in microbiota composition. Changes in the intestinal flora induced by pelvic radiotherapy and their relationship between changes in intestinal flora and the occurrence of radiation-induced diarrhoea (RID) are discussed in this study, providing a theoretical basis for the causes of RID after pelvic radiotherapy.

Diarrhea Induced by Small Molecule Tyrosine Kinase Inhibitors Compared With Chemotherapy: Potential Role of the Microbiome

Small molecule receptor tyrosine kinase inhibitors (SM-TKIs) are among a group of targeted cancer therapies, intended to be more specific to cancer cells compared with treatments, such as chemotherapy, hence reducing adverse events. Unfortunately, many patients report high levels of diarrhea, the pathogenesis of which remains under investigation. In this article, we compare the current state of knowledge of the pathogenesis of chemotherapy-induced diarrhea (CID) in comparison to SM-TKI–induced diarrhea, and investigate how a similar research approach in both areas may be beneficial. To this end, we review evidence that both treatment modalities may interact with the gut microbiome, and as such the microbiome should be investigated for its ability to reduce the risk of diarrhea.

Cross-sectional study to assess the healthcare professionals' knowledge, attitude and practices about probiotics use in Pakistan

OBJECTIVES

The study aimed to assess the knowledge, attitude and practices (KAP) of HCPs regarding the use of probiotics in different health conditions and to identify various barriers that are associated with their use.

METHODS

A cross-sectional study was conducted on 405 HCPs by using a validated self- administered questionnaire for assessing their KAP towards probiotic use. The study data were analysed using descriptive statistics, χ² test and binary logistic regression (BLR).

RESULTS

Among the 405 participants, only 15.1 % of HCPs had good knowledge, while 15.6% had acceptable practices and 89.1% had a positive attitude towards probiotics. The professional position of HCPs was significantly associated with knowledge (p=0.001) and practice (p=0.001). Among all the HCPs, the pharmacists showed a significant association with good knowledge (p=0.016) and good practices (p=0.024) by using BLR. The lack of knowledge about probiotics was a major barrier to the utilisation of probiotics.

CONCLUSIONS

The poor knowledge and practices regarding the use of probiotics have been seen in the current study. While the participants showed a positive attitude towards the utilisation of probiotics. To transform HCPs' positive attitude to their practices and to create awareness regarding probiotic use focused training programmes should be initiated by professional health organisations.

Pitfalls and novel experimental approaches to optimize microbial interventions for chemotherapy-induced gastrointestinal mucositis

There is a growing number of studies implicating gut dysbiosis in mucositis development. However, few studies have shed light on the causal relationship limiting translational potential. Here, we detail the key supportive evidence for microbial involvement, candidate mechanisms by which the microbiome may contribute to mucositis and emerging approaches to model host–microbe interactions with clinical relevance and translational potential.

Immunity, immunotherapy, and rectal cancer: A clinical and translational science review

Rectal cancer remains a challenging disease to treat. Therapy for locally advanced rectal cancer (LARC), the most frequent presentation, has evolved to include a multimodal approach of radiation, chemotherapy, and surgery. While this approach improves local disease control, the distant recurrence rate is nearly 30% and treatment-related morbidity is substantial, thus underscoring the need for new therapeutic approaches with better efficacy and lower side effects. Immunotherapy could potentially fill this need, but its promise is not yet realized in rectal cancer. In this translational science review, we address what is known about how cytotoxic therapies shape rectal cancer immunity and potentially prime the tumor microenvironment for response to immune checkpoint inhibitors and other immunotherapies. We also address the role of current immunotherapies in colorectal cancer and highlight where novel immunotherapy approaches are currently being evaluated in LARC. Finally, we address important future directions in LARC immunotherapy including the need to define optimal therapeutic sequencing, predictive biomarkers, strategies to limit treatment-related side effects and the potential of gut microbiome manipulation to improve outcomes. In summary, this review provides a framework to guide future research and inform immunotherapy trial design so as to advance rectal cancer care.

Use of Shenhuang paste on Shenque point improves chemotherapy induced gastrointestinal toxicity in breast cancer: A protocol for randomized controlled trial

BACKGROUND

Breast cancer, a malignant disorder, occurs in the epithelial tissue of the breast gland. Chemotherapy is the standard treatment for breast cancer, however, the side effect, especially gastrointestinal dysfunction, due to chemotherapy still remain major problems. Traditional Chinese Medicine has been proven therapeutically effective on reducing adverse effects caused by chemotherapy. Shenhuang Plaster.

METHODS

The study is a randomized, placebo-controlled, blind trial. A total of 160 Chinese breast cancer patients will be enrolled and randomly allocated into the experimental group and control group in a 1:1 ratio. Patients in the experimental group will be prescribed Shenhuang plaster application on shenque point (CV8) plus chemotherapy treatment. Patients in the control group will be prescribed placebo plaster application on CV8 plus chemotherapy treatment. The acupoint application will last 3 days. The primary outcome will be the form of faces every day, and the secondary outcomes the symptom score of traditional Chinese medicine, the changes of fecal bacteria and metabolites, serum motilin, gastrin and ghrelin levels.

DISCUSSION

This study is to observe therapeutic effects with Shenhuang plaster application on CV8 to regulate chemotherapy-induced gastrointestinal toxicity in breast cancer patients.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (http://www.chictr.org.cn/showproj.aspx?proj=55262) No. ChiCTR2000034313. Registered on July 2, 2020.

Gastrointestinal cancers: the role of microbiota in carcinogenesis and the role of probiotics and microbiota in anti-cancer therapy efficacy

The gut epithelium is a habitat of a variety of microorganisms, including bacteria, fungi, viruses and Archaea. With the advent of sophisticated molecular techniques and bioinformatics tools, more information on the composition and thus function of gut microbiota was revealed. The gut microbiota as an integral part of the intestinal barrier has been shown to be involved in shaping the mucosal innate and adaptive immune response and to provide protection against pathogens. Consequently, a set of biochemical signals exchanged within microbes and communication between the microbiota and the host have opened a new way of thinking about cancer biology. Probiotics are living organisms which administered in adequate amounts may bring health benefits and have the potential to be an integral part of the prevention/treatment strategies in clinical approaches. Here we provide a comprehensive review of data linking gut microbiota to cancer pathogenesis and its clinical course. We focus on gastrointestinal cancers, such as gastric, colorectal, pancreatic and liver cancer.

A Minireview on Gastrointestinal Microbiota and Radiosusceptibility

Gastrointestinal (GI) microbiota maintains a symbiotic relationship with the host and plays a key role in modulating many important biological processes and functions of the host, such as metabolism, inflammation, immune and stress response. It is becoming increasingly apparent that GI microbiota is susceptible to a wide range of environmental factors and insults, for examples, geographic location of birth, diet, use of antibiotics, and exposure to radiation. Alterations in GI microbiota link to various diseases, including radiation-induced disorders. In addition, GI microbiota composition could be used as a biomarker to estimate radiosusceptibility and radiation health risk in the host. In this minireview, we summarized the documented studies on radiation-induced alterations in GI microbiota and the relationship between GI microbiota and radiosusceptibility of the host, and mainly discussed the possible mechanisms underlying GI microbiota influencing the outcome of radiation response in humans and animal models. Furthermore, we proposed that GI microbiota manipulation may be used to reduce radiation injury and improve the health of the host.

Pre-therapy fasting slows epithelial turnover and modulates the microbiota but fails to mitigate methotrexate-induced gastrointestinal mucositis

BACKGROUND

Recent findings by Tang et al. (2020) show dietary restriction (30%, 2 weeks) prevents methotrexate-induced mortality by modulation of the microbiota, specifically the expansion of Lactobacillus. While fundamentally insightful, upscaling this schedule is a major obstacle to clinical uptake. Here, we evaluate a safe and clinically achievable schedule of pre-therapy fasting for 48 h on microbiota composition, body composition and intestinal proliferation, and assess its impact on the severity of methotrexate-induced gastrointestinal mucositis using a validated preclinical rat model.

METHODS

Age- and weight-matched male Wistar rats were treated with a sublethal dose of 45 mg/kg methotrexate with or without pre-therapy fasting. The impact of acute fasting on epithelial proliferation, body composition and the microbiota was assessed using plasma citrulline, Ki67 immunohistochemistry, miniSpec and 16S rRNA sequencing. The severity of gastrointestinal mucositis was evaluated using plasma citrulline and body weight.

RESULTS

Whilst pre-therapy fasting slowed epithelial proliferation and increased microbial diversity and richness, it also induced significant weight loss and was unable to attenuate the severity of mucositis in both age- and weight-matched groups. In contrast to Tang et al., we saw no expansion of Lactobacillus following acute fasting.

CONCLUSIONS

Our findings suggest that the beneficial effects of acute fasting are masked by the detrimental effects on body weight and composition and lacking influence on Lactobacillus. Future studies should consider alternative fasting schedules or aim to induce comparable microbial and mucosal manipulation without compromising body composition using clinically feasible methods of dietary or microbial intervention.

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.

Multi-donor multi-course faecal microbiota transplantation relieves the symptoms of chronic hemorrhagic radiation proctitis: A case report

RATIONALE

There are many treatments for chronic hemorrhagic radiation colorectal inflammation, but only a few treatments are supported by high-quality research evidence. Studies have shown that the occurrence and development of radiation proctitis are closely associated with the intestinal flora. Animal studies have indicated that faecal microbiota transplantation (FMT) can improve radiation enteropathy in a mouse model.

PATIENT CONCERNS

A 45-year-old female patient suffered from recurrent hematochezia and diarrhea for half a year after radiotherapy and underwent recurrent transfusion treatments. Colonoscopy showed obvious congestion of the sigmoid colon and rectal mucosa, a smooth surface, and bleeding that was easily induced by touch, which are consistent with radiation proctitis. The pathological findings revealed chronic mucosal inflammation. The magnetic resonance imaging examination of the pelvic cavity with a plain scan and enhancement showed changes after radiotherapy and chemotherapy, and no obvious tumor recurrence or metastasis was found. The laboratory examinations excluded pathogen infection.

DIAGNOSES

Based on the history and examinations, the final diagnosis of this patient was chronic hemorrhagic radiation proctitis.

INTERVENTIONS

The patient was treated with a total of 4 individual courses of FMT.

OUTCOMES

After the six-month follow-up, her hematochezia, abdominal pain and diarrhea were relieved. Furthermore, 16S rRNA sequencing of the feces showed that the intestinal bacterial composition of the patient obviously changed after FMT and became similar to that of the donors.

LESSONS

This case report shows that FMT can relieve the symptoms of hematochezia and diarrhea by changing the bacterial community structure in patients with chronic hemorrhagic radiation proctitis.

Microbiota-based approaches to mitigate infectious complications of intensive chemotherapy in patients with acute leukemia

Despite advances in antimicrobial treatments, infection remains a common complication of intensive chemotherapy in patients with acute leukemia. It has become progressively apparent that the current antimicrobial focus has shortcomings that result from disruption of the commensal microbial communities of the gut. These effects, collectively known as dysbiosis, have been increasingly associated worldwide with growing complications such as Clostridioides difficile infection, systemic infections, and antibiotic resistance. A revision of the current practice is overdue. Several innovative concepts have been proposed and tested in animal models and humans, with the overarching goal of preventing damage to the microbiota and facilitating its recovery. In this review, we discuss these approaches, examine critical knowledge gaps, and explore how they may be filled in future research.

Auxiliary antitumor effects of fungal proteins from Hericium erinaceus by target on the gut microbiota

Cancer represents a major disease burden worldwide. Despite continuous advances obtained in medical therapies recently, resistance to standard drugs and adverse effects still represent important causes of therapeutic failure. There is growing evidence that the gut microbiota can affect the response to chemo- and immunotherapeutic drugs by modulating efficacy and/or toxicity, and diet is the most important factor affecting the gut microbiota. In this study, we assessed the auxiliary antitumor effects of immunomodulatory fungal proteins from Hericium erinaceus (HEP) administered with the chemotherapy drug 5-Fluorouracil (5-Fu), and we attempted to identify new potential prebiotic bacteria for auxiliary antitumor treatment. There were 1,455 proteins identified from H. erinaceus. In a xenografted mouse model of cancer, HEP with 5-Fu significantly suppressed tumor growth, inhibited inflammatory markers such as interferon (IFN)-γ, interleukin (IL)-1β, IL-2, IL-6, tumor necrosis factor (TNF)-α, and lipopolysaccharide (LPS), and regulated the expression of Akt, CCDN1, CKD4, FOXM1, MMP7, MYC, PPAR-α, and PPAR-γ. 16S rRNA sequencing showed that HEP ameliorated the dysbacteriosis induced by 5-Fu, as it inhibited certain aerobic and microaerobic bacteria including Parabacteroides, Flavobacteriaceae, Christensenellaceae, Anoxybacillus, Aggregatibacter, Comamonadaceae, Planococcaceae, Desulfovibrionaceae, Sporosarcina, Staphylococcus, Aerococcaceae, and Bilophila in the xenografted mice, and increase some probiotic bacteria such as Bifidobacterium, Gemellales, Blautia, Sutterella, Anaerostipes, Roseburia, Lachnobacterium, Lactobacillus, and Desulfovibrio. This demonstrates that HEP could promote the antitumor efficacy of 5-Fu by improving the microbiota composition, the immune inflammatory response, and homeostasis.

The Microbiota in Hematologic Malignancies

OPINION STATEMENT

There are approximately 1.2 million new hematologic malignancy cases resulting in ~ 690,000 deaths each year worldwide, and hematologic malignancies remain the most commonly occurring cancer in children. Even though advances in anticancer treatment regimens in recent decades have considerably improved survival rates, their cytotoxic effects and the resulting long-term complications pose a significant burden on the patients and the health care system. Therefore, non-toxic treatment modalities are needed to decrease side effects. The human body is the host to approximately 40 trillion microbes, known as the human microbiota. The large majority of the microbiota is located in the gastrointestinal tract, and is primarily composed of bacteria. The microbiota plays several important physiological roles, ranging from digestive functions to immunological and neural development. Investigating the microbiota in patients with hematologic malignancies has several important implications. The microbiota affects hematopoiesis, and influences the efficacies of chemotherapy and antimicrobial treatments. Determination of the microbiota composition and diversity could be an important part of risk stratification in the future, and may also take part to personalize antimicrobial treatments. Modulation of the microbiota via probiotics or fecal transplant can potentially be involved in reducing side effects of chemotherapy, and eliminating multiple drug resistant strains in patients with hematologic malignancies.

Probiotic Supplementation Decreases Chemotherapy-induced Gastrointestinal Side Effects in Patients With Acute Leukemia

INTRODUCTION

In children with acute leukemia, gut microbiota is modified secondary to chemotherapy administration, leading to gastrointestinal side effects. Probiotics are microorganisms that can restore gut microbiota and may help alleviate gastrointestinal symptoms. The aim of this pilot study was to assess the effects of probiotic supplementation on chemotherapy-induced gastrointestinal side effects in children with acute leukemia (AL).

METHODS

In this randomized pilot study, patients under 17 years of age diagnosed with AL who were on remission induction or remission reinduction chemotherapy were randomly assigned to receive probiotic supplementation (a concentration of 5×109 CFU per sachet was administered at a standard dose twice daily, by mouth) or no probiotic supplementation. The primary endpoint was the prevalence of gastrointestinal side effects. Vomiting, nausea, flatulence, dyspepsia, diarrhea, constipation, abdominal pain, and abdominal distention were assessed in both groups.

RESULTS

Gastrointestinal side effects were less prevalent in the probiotic group, and 3 of the 8 gastrointestinal side effects (nausea, vomiting, and abdominal distension) significantly decreased in the probiotic group (P<0.05). We found for diarrhea a relative risk of 0.5 (95% confidence interval [CI], 0.2-1.2; P=0.04); for nausea an RR of 0.5 (95% CI, 0.4-0.8; P=0.04) and for vomiting an RR of 0.4 (95% CI, 0.2-0.9; P=0.04).

CONCLUSIONS

Daily supplementation with Lactobacillus rhamnosus reduced chemotherapy-induced gastrointestinal side effects in children with AL.

Lactobacillus rhamnosus GG protects the intestinal epithelium from radiation injury through release of lipoteichoic acid, macrophage activation and the migration of mesenchymal stem cells

OBJECTIVE

Lactobacillus rhamnosus GG (LGG), a probiotic, given by gavage is radioprotective of the mouse intestine. LGG-induced radioprotection is toll-like receptor 2 (TLR2) and cyclooxygenase-2 (COX-2)-dependent and is associated with the migration of COX-2+mesenchymal stem cells (MSCs) from the lamina propria of the villus to the lamina propria near the crypt epithelial stem cells. Our goals were to define the mechanism of LGG radioprotection including identification of the TLR2 agonist, and the mechanism of the MSC migration and to determine the safety and efficacy of this approach in models relevant to clinical radiation therapy.

DESIGN

Intestinal radioprotection was modelled in vitro with cell lines and enteroids as well as in vivo by assaying clinical outcomes and crypt survival. Fractionated abdominal and single dose radiation were used along with syngeneic CT26 colon tumour grafts to assess tumour radioprotection.

RESULTS

LGG with a mutation in the processing of lipoteichoic acid (LTA), a TLR2 agonist, was not radioprotective, while LTA agonist and native LGG were. An agonist of CXCR4 blocked LGG-induced MSC migration and LGG-induced radioprotection. LGG given by gavage induced expression of CXCL12, a CXCR4 agonist, in pericryptal macrophages and depletion of macrophages by clodronate liposomes blocked LGG-induced MSC migration and radioprotection. LTA effectively protected the normal intestinal crypt, but not tumours in fractionated radiation regimens.

CONCLUSIONS

LGG acts as a 'time-release capsule' releasing radioprotective LTA. LTA then primes the epithelial stem cell niche to protect epithelial stem cells by triggering a multicellular, adaptive immune signalling cascade involving macrophages and PGE2 secreting MSCs.

TRIAL REGISTRATION NUMBER

NCT01790035; Pre-results.

Gut microbiota: implications for radiotherapy response and radiotherapy-induced mucositis

Radiotherapy is a mainstay of solid tumor management but can be associated with unacceptable levels of off-target tissue toxicity which impact treatment outcomes and patients' quality of life. Tumour response to radiotherapy and the frequency and severity of radiotherapy-induced toxicities, especially mucositis, varies among patients. Gut microbiota has been found to modulate both the efficacy and toxicity of some types of cancer chemotherapies and immunotherapies but has yet to be investigated thoroughly in the setting of radiotherapy. Area covered: In this review, we discuss the potential role of gut microbiota on modulating radiotherapy-induced oral and gastrointestinal mucositis and the anti-tumor response to radiotherapy through modulation of immune responses. Expert opinion: The gut microbiota plays a major role in the modulation of systemic immune responses, which influence both radiotherapy response and gastrointestinal toxicities such as mucositis. Hence, investigating the gut microbiota link to the variation in radiotherapy responses and toxicities among patients is warranted. Future targeting of these responses with a patient-tailored restoration of optimal microbial composition could lead to a new era of mucositis prevention and enhanced tumor responses.

Probiotics: If It Does Not Help It Does Not Do Any Harm. Really?

Probiotics per definition should have beneficial effects on human health, and their consumption has tremendously increased in the last decades. In parallel, the amount of published material and claims for their beneficial efficacy soared continuously. Recently, multiple systemic reviews, meta-analyses, and expert opinions expressed criticism on their claimed effects and safety. The present review describes the dark side of the probiotics, in terms of problematic research design, incomplete reporting, lack of transparency, and under-reported safety. Highlighted are the potential virulent factors and the mode of action in the intestinal lumen, risking the physiological microbiome equilibrium. Finally, regulatory topics are discussed to lighten the heterogeneous guidelines applied worldwide. The shift in the scientific world towards a better understanding of the human microbiome, before consumption of the probiotic cargo, is highly endorsed. It is hoped that better knowledge will extend the probiotic repertoire, re-confirm efficacy or safety, establish their efficacy and substantiate their beneficial effects.

Adjunctive fecal microbiota transplantation in supportive oncology: Emerging indications and considerations in immunocompromised patients

FMT has gained enormous momentum in the treatment of acute inflammatory and infectious diseases. Despite an encouraging safety profile, FMT has been met with caution in the oncological setting due to perceived infectious risks in immunocompromised patients. Theoretical risks aside, the application of FMT in oncology may stand to benefit patients, via modulation of treatment efficacy and the mitigation of treatment complications. Here, we summarize most recent safety data of FMT in immunocompromised cohorts, including people with cancer, highlighting that FMT may actually provide protection against bacterial translocation via introduction of a diverse microbiome and restoration of epithelial defenses. We also discuss the emerging translational applications of FMT within supportive oncology, including the prevention and treatment of graft vs. host disease and sepsis, treatment of immunotherapy-induced colitis and restoration of the gut microbiome in survivors of childhood cancer.

Microbiota in cancer development and treatment

PURPOSE

Human microbiota comprises of a variety of organisms ranging from bacterial species to viruses, fungi, and protozoa which are present on the epidermal and mucosal barriers of the body. It plays a key role in health and survival of the host by regulation of the systemic functions. Its apparent functions in modulation of the host immune system, inducing carcinogenesis and regulation of the response to the cancer therapy through a variety of mechanisms such as bacterial dysbiosis, production of genotoxins, pathobionts, and disruption of the host metabolism are increasingly becoming evident.

METHODS

Different electronic databases such as PubMed, Google Scholar, and Web of Science were searched for relevant literature which has been reviewed in this article.

RESULTS

Characterization of the microbiome particularly gut microbiota, understanding of the host-microbiota interactions, and its potential for therapeutic exploitation are necessary for the development of novel anticancer therapeutic strategies with better efficacy and lowered off-target side effects.

CONCLUSION

In this review, the role of microbiota is explained in carcinogenesis, mechanisms of microbiota-mediated carcinogenesis, and role of gut microbiota in modulation of cancer therapy.

Adjunctive Treatments for the Prevention of Chemotherapy- and Radiotherapy-Induced Mucositis

Background: Chemoradiotherapy-associated mucositis can manifest as pain, inflammation, dysphagia, diarrhea, weight loss, rectal bleeding, and infection. Mucositis is a major dose-limiting side effect of chemotherapy, affecting nutritional intake and oral and intestinal function. Despite several interventions being available, there is a need for safe and effective preventative and treatment options for treatment-induced mucositis. The goals of this review are to discuss interventions based on foods and natural products and present the research to date. Methods: A narrative literature review identified 60 clinical studies examining various nutritional compounds and 20 examining probiotics. 9 studies on probiotics for the prevention of diarrhea were also assessed on methodological quality and limitations identified. Results: Several compounds have been posited as useful adjuvants for cancer treatment–related mucositis. Probiotics demonstrate efficacy for the prevention and treatment of chemoradiotherapy-induced gastrointestinal toxicity without significant side effects. Glutamine and activated charcoal were reported to reduce chemotherapy-induced diarrhea but not radiation-induced intestinal mucositis. Honey has been reported to decrease treatment interruptions, weight loss, and delays the onset of oral mucositis. Zinc, glutamine, and topical vitamin E were demonstrated efficacy for oral mucositis. Conclusion: There is plausible clinical evidence for the administration of several adjunctive treatments for the prevention and treatment of mucositis. Probiotics were reported to reduce the burden of intestinal mucositis and treatment-induced diarrhea. Activated charcoal and glutamine are beneficial for chemotherapy-induced diarrhea, whereas the administration of honey, zinc, and glutamine reduce the risk of developing oral mucositis during chemotherapy or radiotherapy.

Role of toll-like receptor 4 (TLR4)-mediated interleukin-6 (IL-6) production in chemotherapy-induced mucositis

Despite significant advances in our ability to treat cancer, cytotoxic chemotherapy continues to be the mainstay treatment for many solid tumours. Chemotherapy is commonly associated with a raft of largely manageable adverse events; however, gastrointestinal (GI) toxicity (also termed mucositis) remains a significant challenge with little in the way of preventative and therapeutic options. The inability to manage GI complications likely reflects our incomplete understanding of its aetiology and the idiosyncrasies of each chemotherapeutic agent. This review highlights aims to provide a narrative for the involvement of Toll-like receptor (TLR4) in the development of chemotherapy-induced GI mucositis, an already emerging theme within this field. Particular focus will be placed upon the signalling interaction between TLR4 and interleukin (IL)-6. This parallels recent preclinical findings showing that TLR4 knockout mice, which are protected from developing severe GI mucositis, completely lack an IL-6 response. As such, we suggest that this signalling pathway presents as a novel mechanism with potential for therapeutic intervention.