Changes in Gut Microbiome Associated With Co-Occurring Symptoms Development During Chemo-Radiation for Rectal Cancer: A Proof of Concept Study

Influence of Gut Microbiota-Mediated Immune Regulation on Response to Chemotherapy

The involvement of the gut microbiota in anti-cancer treatment has gained increasing attention. Alterations to the structure and function of the gut bacteria are important factors in the development of cancer as well as the efficacy of chemotherapy. Recent studies have confirmed that the gut microbiota and related metabolites influence the pharmacological activity of chemotherapeutic agents through interactions with the immune system. This review aims to summarize the current knowledge of how malignant tumor and chemotherapy affect the gut microbiota, how the gut microbiota regulates host immune response, and how interactions between the gut microbiota and host immune response influence the efficacy of chemotherapy. Recent advances in strategies for increasing the efficiency of chemotherapy based on the gut microbiota are also described. Deciphering the complex homeostasis maintained by the gut microbiota and host immunity provides a solid scientific basis for bacterial intervention in chemotherapy.

The association between the gut microbiome and fatigue in individuals living with cancer: a systematic review

PURPOSE

Fatigue is the most distressing symptom for individuals with cancer. While numerous studies have investigated biological pathways that could underlie the mechanism of fatigue, the cause of fatigue remains unclear. This review aimed to investigate the association between gut microbial composition and fatigue in individuals with cancer.

METHODS

Medline (PubMed), Embase (Elsevier), and CINAHL Complete (Ebscohost) were systemically searched on March 30, 2023, for articles investigating gut microbial composition (relative abundance, alpha diversity, and beta diversity) and fatigue in individuals with cancer; no limitations were placed on dates, participant age, nor cancer type/treatment.

RESULTS

Microbial composition in the form of relative abundance was correlated with fatigue in six of the seven articles. A high relative abundance of g_Ruminoccocus was observed in individuals with low fatigue. An elevated relative abundance of g_Escherichia and f_Enterobacteriaceae was associated with high fatigue. However, other associations between fatigue and relative abundance composition, such as with g_Bifidobacterium and g_Faecalibacterium, had conflicting results. For alpha diversity and fatigue, the findings were contradictory; the association between beta diversity and fatigue was unclear due to conflicting results.

CONCLUSIONS

Pro-inflammatory bacteria, such as f_Enterobacteriaceae, were more commonly associated with higher fatigue scores, while anti-inflammatory or short-chain fatty acid producing bacteria, such as g_Ruminoccocus, were linked with lower fatigue scores in individuals with cancer. The relationship between alpha and beta diversity and fatigue was inconclusive. Further investigation is needed to clarify whether gut microbial changes play a correlative or causal role in the development of fatigue in individuals with cancer.

Multi-omics analysis of the gut microbiome and metabolites associated with the psychoneurological symptom cluster in children with cancer receiving chemotherapy

BACKGROUND

Children with cancer receiving chemotherapy commonly report a cluster of psychoneurological symptoms (PNS), including pain, fatigue, anxiety, depression, and cognitive dysfunction. The role of the gut microbiome and its functional metabolites in PNS is rarely studied among children with cancer. This study investigated the associations between the gut microbiome-metabolome pathways and PNS in children with cancer across chemotherapy as compared to healthy children.

METHODS

A case-control study was conducted. Cancer cases were recruited from Children's Healthcare of Atlanta and healthy controls were recruited via flyers. Participants reported PNS using the Pediatric Patient-Reported Outcomes Measurement Information System. Data for cases were collected pre-cycle two chemotherapy (T0) and post-chemotherapy (T1), whereas data for healthy controls were collected once. Gut microbiome and its metabolites were measured using fecal specimens. Gut microbiome profiling was performed using 16S rRNA V4 sequencing, and metabolome was performed using an untargeted liquid chromatography-mass spectrometry approach. A multi-omics network integration program analyzed microbiome-metabolome pathways of PNS.

RESULTS

Cases (n = 21) and controls (n = 14) had mean ages of 13.2 and 13.1 years. For cases at T0, PNS were significantly associated with microbial genera (e.g., Ruminococcus, Megasphaera, and Prevotella), which were linked with carnitine shuttle (p = 0.0003), fatty acid metabolism (p = 0.001) and activation (p = 0.001), and tryptophan metabolism (p = 0.008). Megasphaera, clustered with aspartate and asparagine metabolism (p = 0.034), carnitine shuttle (p = 0.002), and tryptophan (p = 0.019), was associated with PNS for cases at T1. Gut bacteria with potential probiotic functions, along with fatty acid metabolism, tryptophan, and carnitine shuttle, were more clustered in cancer cases than the control network and this linkage with PNS needs further studies.

CONCLUSIONS

Using multi-omics approaches, this study indicated specific microbiome-metabolome pathways linked with PNS in children with cancer across chemotherapy. Due to limitations such as antibiotic use in cancer cases, these findings need to be further confirmed in a larger cohort.

Associations of the gut microbiome with psychoneurological symptom cluster in women with gynecologic cancers: a longitudinal study

PURPOSE

The present study aimed to evaluate the associations between the gut microbiome and psychoneurological symptoms (PNS) cluster in women with gynecologic cancers over time.

METHODS

In this secondary data analysis, 19 women with cervical and endometrial cancers treated with radiotherapy were followed at pre-treatment, 6-8 weeks, and 6 months post-treatment. To measure symptoms, Functional Assessment of Cancer Therapy-General (FACT-G) and Patient Health Questionnaire-9 (PHQ-9) were used. An average Z score of at least three out of five symptoms was computed as the PNS cluster total score. Rectal swabs were also collected at the same time points and sequenced using 16S rRNA V4 regions. The Kruskal-Wallis and permutational multivariable analysis of variance tests were used to compare α- and β-diversity between patients with high and low PNS cluster. The linear discriminant analysis effect size (LEfSe) tested taxa differences between study groups. Also, the linear mixed-effect model was used to evaluate the association of the gut microbiome and the PNS cluster over cancer treatment.

RESULTS

The patients' mean age was 58 years, 47% Black, 52% single/divorced, and 66% had college or above education. Among the participants, 63% had endometrial cancer with stage I disease. There was a different taxonomy profile between patients with high and low PNS. Patients with high PNS had a lower α-diversity than those with low PNS (Shannon, p = 0.03, evenness, p = 0.03). The mixed effects model results showed that low α-diversity and abundance of Fusicatenibacter and Ruminococcus were associated with high PNS cluster over cancer treatment.

CONCLUSION

The association between the gut microbiome and PNS cluster suggest that the gut microbiota plays a role in developing the PNS cluster. Future larger studies are required to shed light on the gut microbiota role in symptom development in gynecologic cancer patients.

[Relationship between chronic radiation enteritis of cervical cancer and gut microbiota]

OBJECTIVE

To explore the relationship between gut microbiota and chronic radiation enteritis of cervical cancer patients.

METHODS

Fecal samples were collected from 34 patients with cervical cancer who had received radiotherapy for at least 6 months but less than 2 years. The patients were divi-ded into mild toxicity group (mild, M) with no symptoms or mild symptoms and severe toxicity group (severe, S) with severe symptoms by clinical diagnosis of radiation enteritis, modified inflammatory bo-wel disease questionnaire (IBDQ) and Vaizey questionnaire. DNA extracted from fecal samples was sequenced and analyzed by 16S rRNA sequencing method. The analysis indexes included α-diversity, β-diversity, taxonomic composition analysis, taxonomic hierarchy tree and linear discriminant analysis (LDA) effect size (LEfSe).

RESULTS

From the perspective of species diversity, most indices of α diversity in group M were higher than those in group S. Although there was no significant difference, it also indicated a correlation between low species diversity and severity of intestinal symptoms to some extent. There was also a significant difference in the distribution of β diversity between the two groups, indicating that the microbial characteristics were different between the two groups. From the perspective of species composition, the M group had higher Firmicutes [66.5% (M) vs. 56.0% (S)] and lower Proteobacteria [4.1% (M) vs. 13.9% (S)] than the S group at the level of phyla. At the level of genus, there were also significant differences between the two groups: Shigella [2.7% (M) vs. 8.5% (S)], Faeca-libacterium [7.0% (M) vs. 2.7% (S)], Lachnospiraceae_Clostridium [1.3% (M) vs. 4.7% (S)]. Through LEfSe also found some species with statistically significant differences between the two groups. The abundance of Peptoniphilus, Azospirillum and Actinomyces in group M was significantly higher, while the abundance of Veillonellaceae, Rhodobacteraceae, and Rhodobacterales in group S was significantly higher. The taxonomic hierarchy tree also intuitively showed the difference in species composition between the two groups at each taxonomic level in space.

CONCLUSION

The severity of chronic radiation enteritis of cervical cancer is closely related to the characteristics and composition of gut microbiota.

New Insights into the Relationship between Gut Microbiota and Radiotherapy for Cancer

Cancer is the second most common cause of death among humans in the world, and the threat that it presents to human health is becoming more and more serious. The mechanisms of cancer development have not yet been fully elucidated, and new therapies are changing with each passing day. Evidence from the literature has validated the finding that the composition and modification of gut microbiota play an important role in the development of many different types of cancer. The results also demonstrate that there is a bidirectional interaction between the gut microbiota and radiotherapy treatments for cancer. In a nutshell, the modifications of the gut microbiota caused by radiotherapy have an effect on tumor radiosensitivity and, as a result, affect the efficacy of radiotherapy and show a certain radiation toxicity, which leads to numerous side effects. What is of new research significance is that the "gut-organ axis" formed by the gut microbiota may be one of the most interesting potential mechanisms, although the relevant research is still very limited. In this review, we combine new insights into the relationship between the gut microbiota, cancer, and radiotherapy. Based on our current comprehensive understanding of this relationship, we give an overview of the new cancer treatments based on the gut microbiota.

The Role of the Microbiome on the Pathogenesis and Treatment of Colorectal Cancer

The gut microbiome has long been known to play a role in various aspects of health modulation, including the pathogenesis of colorectal cancer (CRC). With immunotherapy recently emerging as a successful treatment in microsatellite instability high (MSI-high) CRC, and with a newly demonstrated involvement of the gut microbiome in the modulation of therapeutic responses, there has been an explosion of research into the mechanisms of microbial effects on CRC. Harnessing and reprogramming the microbiome may allow for the expansion of these successes to broader categories of CRC, the prevention of CRC in high-risk patients, and the enhancement of standard treatments. In this review, we pull together both well-documented phenomena and recent discoveries that pertain to the microbiome and CRC. We explore the microbial mechanisms associated with CRC pathogenesis and progression, recent advancements in CRC systemic therapy, potential options for diagnosis and prevention, as well as directions for future research.

Metabolic Pathways Associated With Psychoneurological Symptoms in Children With Cancer Receiving Chemotherapy

CONTEXT

Children with cancer undergoing chemotherapy experience a cluster of psychoneurological symptoms (PNS), including pain, fatigue, anxiety, and depressive symptoms. Metabolomics is promising to differentiate metabolic pathways associated with the PNS cluster.

OBJECTIVES

Identify metabolic pathways associated with the PNS cluster in children with cancer before and after chemotherapy.

METHODS

Pain, fatigue, anxiety, and depressive symptoms were assessed using the Pediatric PROMIS scales. T-scores were computed and divided dichotomously by a cutoff point of 50; the PNS cluster was a sum of the four symptoms ranging from 0 (all T-scores <50) to 4 (all T-scores ≥50). Serum metabolites were processed using liquid chromatography mass-spectrometry untargeted metabolomics approach. Linear regression models examined metabolites associated with the PNS cluster. Metabolic pathway enrichment analysis was performed.

RESULTS

Participant demographics (n = 40) were 55% female, 60% white, 62.5% aged 13-19 years, and 62.5% diagnoses of Hodgkin's lymphoma and B-cell acute lymphocytic leukemia. Among 9276 unique metabolic features, 454 were associated with pain, 281 with fatigue, 596 with anxiety, 551 with depressive symptoms, and 300 with the PNS cluster across one chemotherapy cycle. Fatty acids pathways were associated with pain: de novo fatty acid biosynthesis (p < .001), fatty acid metabolism (p = .001), fatty acid activation (p = .004), and omega-3 fatty acid metabolism (p = .009). Tryptophan amino acid pathway was associated with fatigue (p < .001), anxiety (p = .015), and the PNS cluster (p = .037). Carnitine shuttle was associated with the PNS cluster (p = .015).

CONCLUSION

Fatty acids and amino acids pathways were associated with PNS in children undergoing chemotherapy. These findings require further investigation in a larger sample.

Sleep Deficiency: A Symptoms Perspective: Exemplars from Chronic Heart Failure, Inflammatory Bowel Disease, and Breast Cancer

Sleep deficiency is associated with disabling daytime symptoms, including excessive daytime sleepiness (EDS) and fatigue. The purpose of this article is to discuss the contributions of sleep deficiency and sleep disorders to fatigue and EDS among people with chronic conditions. We use exemplars from the literature on chronic heart failure, inflammatory bowel disease, and breast cancer to (1) describe the prevalence of fatigue and EDS and their consequences; (2) examine the evidence for the contributions of sleep deficiency and sleep disorders to these symptoms; and (3) recommend implications for future research and practice.

Exploring the links among inflammation and gut microbiome with psychoneurological symptoms and gastrointestinal toxicities in gynecologic cancers: a systematic review

INTRODUCTION

Emerging evidence highlights the roles the gut microbiome and the immune system, integral parts of the gut-brain axis, play in developing various symptoms in cancer patients. The purpose of this systematic review was to describe the roles of inflammatory markers and the gut microbiome, as well as to describe their associations with psychoneurological symptoms and gastrointestinal toxicities in women with gynecologic cancers.

METHODS

A comprehensive literature search was conducted in PubMed, Embase, and Web of Science from January 2000 to February 2021. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines were utilized to screen the found articles. The quality of the included studies was assessed using the Mixed Method Assessment Tool. In the included studies, various inflammatory markers and gut microbiome diversity and patterns were measured.

RESULTS

Sixteen studies met the eligibility criteria and were included in this systematic review. While there were discrepancies in the associations between various inflammatory markers and symptoms, most of the studies showed positive correlations between interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) and cancer-related psychoneurological symptoms and gastrointestinal toxicities in gynecologic cancer patients. Although there was no consensus in alpha diversity, studies showed significant dissimilarity in the microbial communities (beta diversity) in patients with gastrointestinal toxicities compared with patients without symptoms or healthy controls. Studies also reported inconsistent findings in the abundance of bacteria at different taxonomic levels. Radiation enteritis-derived microbiota could stimulate TNF-α and interleukin 1 beta (IL-1β) secretion.

CONCLUSIONS

Alteration of inflammatory markers, the gut microbiome, and their associations show emerging evidence in the development of psychoneurological symptoms and gastrointestinal toxicities in women with gynecologic cancers. More studies on the interactions between the immune system and the gut microbiome, two integral parts of the gut-brain axis, are required to shed light on the roles they play in symptom development.

The Interplay among Radiation Therapy, Antibiotics and the Microbiota: Impact on Cancer Treatment Outcomes

Radiation therapy has been used for more than a century, either alone or in combination with other therapeutic modalities, to treat most types of cancer. On average, radiation therapy is included in the treatment plans for over 50% of all cancer patients, and it is estimated to contribute to about 40% of curative protocols, a success rate that may reach 90%, or higher, for certain tumor types, particularly on patients diagnosed at early disease stages. A growing body of research provides solid support for the existence of bidirectional interaction between radiation exposure and the human microbiota. Radiation treatment causes quantitative and qualitative changes in the gut microbiota composition, often leading to an increased abundance of potentially hazardous or pathogenic microbes and a concomitant decrease in commensal bacteria. In turn, the resulting dysbiotic microbiota becomes an important contributor to worsen the adverse events caused in patients by the inflammatory process triggered by the radiation treatment and a significant determinant of the radiation therapy anti-tumor effectiveness. Antibiotics, which are frequently included as prophylactic agents in cancer treatment protocols to prevent patient infections, may affect the radiation/microbiota interaction through mechanisms involving both their antimicrobial activity, as a mediator of microbiota imbalances, and their dual capacity to act as pro- or anti-tumorigenic effectors and, consequently, as critical determinants of radiation therapy outcomes. In this scenario, it becomes important to introduce the use of probiotics and/or other agents that may stabilize the healthy microbiota before patients are exposed to radiation. Ultimately, newly developed methodologies may facilitate performing personalized microbiota screenings on patients before radiation therapy as an accurate way to identify which antibiotics may be used, if needed, and to inform the overall treatment planning. This review examines currently available data on these issues from the perspective of improving radiation therapy outcomes.

Gut Microbiome and Its Associations With Acute and Chronic Gastrointestinal Toxicities in Cancer Patients With Pelvic Radiation Therapy: A Systematic Review

Aim

Pelvic radiation therapy (RT) can impact the gut microbiome in patients with cancer and result in gastrointestinal (GI) toxicities. The purpose of this systematic review was to describe the effects of RT on the gut microbiome and the associations between the gut microbiome and GI toxicities in patients treated with pelvic RT.

Methods

PubMed, Embase, and Web of Science databases were searched from their earliest records to August 2020. The articles screening process adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The Mixed Method Assessment Tool was used to assess the methodological quality for each included study. All study findings were synthesized and presented in narrative format. Thirteen studies were included. The gut microbiome of fecal samples was analyzed using 16S rRNA sequencing approaches.

Results

There were disparities in alpha and beta diversities that existed across the studies. Divergent results were found among various phyla, including Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria, Cyanobacteria, Fusobacteria, and Deinococcus-Thermus. Moreover, alteration in the gut microbiome diversity and abundance related to cancer treatment was associated with pelvic toxicities, specifically diarrhea. Following treatment, increases in the abundance of Bacteroides was associated with diarrhea and radiation enteritis.

Conclusions

Pelvic RT can disrupt the diversity and abundance of commensal gut microorganisms. A dysbiotic gut microbiome showed a promising association with radiation enteritis through alterations of the intestinal barrier function, innate immunity, and intestinal repair mechanisms; however, confounders, such as diet, were not thoroughly addressed.

Human Microbiome: Understanding the Role of the Gut Microbiome and Implications for Oncology Nursing Care

By understanding the human microbiome and its influencing factors, oncology nurses in clinical practice can educate, screen, and monitor patients with cancer who have a higher risk of gut microbiome dysbiosis. Knowledge of the gut microbiome and its impact on cancer outcomes can help oncology nurses interpret associations between the gut microbiome and treatment- related toxicities and symptoms. Oncology nurses can guide patients to build a healthy gut microbiome across the trajectory of cancer treatment and survivorship.

Biobehavioral Research and Hematopoietic Stem Cell Transplantation: Expert Review from the Biobehavioral Research Special Interest Group of the American Society for Transplantation and Cellular Therapy

Hematopoietic stem cell transplantation (HCT) is a potentially curative treatment for many hematologic conditions. Despite advances in conditioning and supportive measures, however, there remain significant comorbidities that threaten survivorship. Adverse effects of stress-related biobehavioral processes-defined here as the interactions of behavioral, psychological, and socioenvironmental factors with biology-impact immune recovery and function and are particularly salient in the HCT context, given the importance of immune reconstitution for improved survivorship. However, biobehavioral processes have been underinvestigated in this vulnerable group compared with other cancer populations. Here the Biobehavioral Research Special Interest Group (SIG) of the American Society for Transplantation and Cellular Therapy provides an expert review to inform research directions explicating the biological correlates of behavioral symptoms and evaluate the impact of these on HCT outcomes. The goal of this expert review is to provide a foundation for advancing science that effectively integrates behavioral and biological processes to optimize quality of life and improve clinical outcomes for HCT recipients.

Association of Radiotherapy-Related Intestinal Injury and Cancer-related Fatigue: A Brief Review and Commentary

Radiotherapy treatment-induced intestinal injury and gut microbial perturbation/dysbiosis have been implicated in the pathobiology of cancer-related fatigue. The objective of this brief review was to explore the available evidence of the relationship between intestinal injury and self-reported fatigue, especially among cancer patients. The scientific evidence-including our own-linking gut mucosal barrier dysfunction and gut microbial perturbation/dysbiosis induced by cancer treatment with worsening of cancer related fatigue (perhaps through the gut-brain axis) is limited but promising. Emerging data suggest that lifestyle interventions and the administration of specific probiotics may favorably modulate the gut microbiota and potentially mediate beneficial effects leading to improvements in fatigue.

Co-Occurrence of Symptoms and Gut Microbiota Composition Before Neoadjuvant Chemotherapy and Radiation Therapy for Rectal Cancer: A Proof of Concept

PURPOSE

To examine a) whether there are significant differences in gut microbial diversity and in the abundance of gut microbial taxa; and b) differences in predicted functional pathways of the gut microbiome between those participants with high co-occurring symptoms and those with low co-occurring symptoms, prior to neoadjuvant chemotherapy and radiation therapy (CRT) for rectal cancer.

METHODS

Rectal cancer patients (n = 41) provided stool samples for 16 S rRNA gene sequencing and symptom ratings for fatigue, sleep disturbance, and depressive symptoms prior to CRT. Descriptive statistics were computed for symptoms. Gut microbiome data were analyzed using QIIME2, LEfSe, and the R statistical package.

RESULTS

Participants with high co-occurring symptoms (n = 19) had significantly higher bacterial abundances of Ezakiella, Clostridium sensu stricto, Porphyromonas, Barnesiella, Coriobacteriales Incertae Sedis, Synergistiaceae, Echerichia-Shigella, and Turicibacter compared to those with low co-occurring symptoms before CRT (n = 22). Biosynthesis pathways for lipopolysaccharide, L-tryptophan, and colanic acid building blocks were enriched in participants with high co-occurring symptoms. Participants with low co-occurring symptoms showed enriched abundances of Enterococcus and Lachnospiraceae, as well as pathways for β-D-glucoronosides, hexuronide/hexuronate, and nicotinate degradation, methanogenesis, and L-lysine biosynthesis.

CONCLUSION

A number of bacterial taxa and predicted functional pathways were differentially abundant in patients with high co-occurring symptoms compared to those with low co-occurring symptoms before CRT for rectal cancer. Detailed examination of bacterial taxa and pathways mediating co-occurring symptoms is warranted.

Gut Microbiota and Depressive Symptoms at the End of CRT for Rectal Cancer: A Cross-Sectional Pilot Study

BACKGROUND

The role of alterations in gut microbiota composition (termed dysbiosis) has been implicated in the pathobiology of depressive symptoms; however, evidence remains limited. This cross-sectional pilot study is aimed at exploring whether depressive symptom scores changed during neoadjuvant chemotherapy and radiation therapy to treat rectal cancer, and if gut microbial taxa abundances and predicted functional pathways correlate with depressive symptoms at the end of chemotherapy and radiation therapy.

METHODS

40 newly diagnosed rectal cancer patients (ages 28-81; 23 males) were assessed for depressive symptoms using the Hamilton Rating Scale for Depression (HAM-D) and provided stool samples for 16S rRNA sequencing. Gut microbiome data were analyzed using QIIME2, and correlations and regression analyses were performed in R.

RESULTS

Participants had significantly higher depressive symptoms at the end as compared to before CRT. The relative abundances of Gemella, Bacillales Family XI, Actinomyces, Streptococcus, Lactococcus, Weissella, and Leuconostocaceae were positively correlated (Spearman's rho = 0.42 to 0.32), while Coprobacter, Intestinibacter, Intestimonas, Lachnospiraceae, Phascolarctobacterium, Ruminiclostridium, Ruminococcaceae (UCG-005 and uncultured), Tyzzerella, and Parasutterella (Spearman's rho = -0.43 to - 0.31) were negatively correlated with HAM-D scores. Of the 14 predicted MetaCyc pathways that correlated with depressive symptom scores at the end of CRT, 11 (79%) were associated with biosynthetic pathways.

CONCLUSIONS

Significant bacterial taxa and predicted functional pathways correlated with depressive symptoms at the end of chemotherapy and radiation therapy for rectal cancer which warrants further examination and replication of our findings.