The Potential Effect of Oral Microbiota in the Prediction of Mucositis During Radiotherapy for Nasopharyngeal Carcinoma

Interconnected influences of tumour and host microbiota on treatment response and side effects in nasopharyngeal cancer

This study elucidates the intricate relationship between nasopharyngeal carcinoma (NPC), a significant malignancy predominant in Asia with notable global incidence and mortality rates, and the host microbiota, including those of tumour, nasal, nasopharyngeal, oral, oropharyngeal, and gut communities. It underscores how the composition and diversity of microbiota are altered in NPC, delving into their implications for disease pathogenesis, treatment response, and the side effects of therapies. A consistent reduction in alpha diversity across oral, nasal, and gut microbiomes in NPC patients compared to healthy individuals signals a distinct microbial signature indicative of the diseased state. The study also shows unique microbial changes tied to different NPC stages, indicating a dynamic interplay between disease progression and microbiota composition. Patients with specific microbial profiles exhibit varied responses to chemotherapy and immunotherapy, underscoring the potential for treatment personalisation based on microbiota analysis. Furthermore, the side effects of NPC treatments, such as oral mucositis, are intensified by shifts in microbial communities, suggesting a direct link between microbiota composition and treatment tolerance. This nexus offers opportunities for interventions aimed at modulating the microbiota to alleviate side effects, improve quality of life, and potentially enhance treatment efficacy. Highlighting the dual potential of microbiota as both a therapeutic target and a biomarker for NPC, this review emphasises its significance in influencing treatment outcomes and side effects, heralding a new era in NPC management through personalised treatment strategies and innovative approaches.

Risk factor and prediction model development for severe radiation-induced oral mucositis in head and neck tumors

Aim: This article aims to identify risk factors for severe radiation-induced oral mucositis (RIOM) in head and neck cancer (HNC) patients. In addition, we intend to establish a predictive model in patients undergoing intensity-modulated radiotherapy. Patients & methods: In this retrospective study, several HNC patients (n = 179) treated at Zhejiang Provincial People's Hospital from January 2019 to June 2023 were considered. The recruited subjects were divided into modeling and validation groups. The experimental data on clinical characteristics and treatment were collected and analyzed to identify predictive factors for severe RIOM based on the logistic regression approach. Results: The results indicated that severe RIOM occurred in 55.3% of patients. Accordingly, significant predictors included smoking history, diabetes, concurrent chemotherapy, cumulative radiation dose and weight loss of ≥5% in relative to admission weight. A nomogram based on these factors was validated, showing excellent predictive accuracy. Conclusion: In summary, the predictive model could effectively identify high-risk patients for severe RIOM, enabling the design of targeted interventions and improving patient management during radiotherapy.

Oral specimens as a tool for accurate metagenomic analysis: A pilot study

OBJECTIVES

Acute oral mucosal damage, as well as other inflammatory processes seem to be related to dysbiosis of the oral microbiome. The need to study changes in the oral microbiome led us to hypothesize what type of sample would provide the most representative picture of the entire human oral microbiome.

MATERIALS AND METHODS

An observational, and cross-sectional study was carried out. Six healthy adult participants provided 3 different sample types each, that included saliva, oral rinse and mucosal biopsy tissue. We performed 16S rRNA sequencing of the V3-V4 region of the 18 samples using Illumina MiSeq technology.

RESULTS

Participants were 27 ± 6,3 years old. Bacterial alpha diversity was higher in oral rinse samples compared to whole unstimulated saliva and oral mucosa tissue (p = 0,005). However, saliva specimens showed a 56 % relative abundance of identified species followed by a 30 % in oral rinse and only 1 % in tissue samples.

CONCLUSIONS

This study found differences on oral microbiome composition for each type of sample. Oral rinse should be chosen when higher alpha diversity is needed, whereas whole unstimulated saliva should be more appropriate for larger amount of bacterial DNA.

CLINICAL RELEVANCE

The results obtained demonstrate the importance of a correct choice of the optimal type of oral sample for microbiome studies due to the differences found in its composition.

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

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

Post-irradiation dysbiosis in patients with nasopharyngeal carcinoma having received radiotherapy - A pilot study

OBJECTIVE

To compare the changes in the sinonasal mucosa microbiome in patients with nasopharyngeal carcinoma (NPC) before and after radiotherapy (RT), and to explore the pathogenesis of post-irradiation chronic rhinosinusitis (PI-CRS) and its association with dysbiosis.

STUDY DESIGN

Prospective cohort study.

SETTING

Unicenter, Tertiary referral hospital.

METHODS

Included patients newly diagnosed with NPC. Samples of ostiomeatal complex mucosa were collected before and after RT. Microbiome analysis was conducted using 16S rRNA sequencing, and statistical analysis was performed. Subgroup analyses based on RT modality (proton therapy or photon therapy) RESULTS: Total of 18 patients were enrolled in the study, with 62.1% receiving intensity-modulated proton therapy (IMPT). Corynebacterium was the most dominant genus identified in both the pre- and post-RT groups, with a visible increase in Staphylococcus and a decrease in Fusobacterium genus in post-RT group. Alpha-diversity did not significantly differ between groups, although the beta-diversity analysis revealed a dispersed microbiota in the post-RT group. The functional prediction indicated a higher relative abundance of taxonomies associated with biofilm formation in the post-RT group. The subgroup analysis revealed the above changes to be more significant in patients who received photon therapy (Intensity modulated radiation therapy, IMRT).

CONCLUSIONS

This is the first study to analyze the microbiome of patients with NPC after IMPT. We identified similarities between the post-RT microenvironment and that reported in patients with CRS, with a more apparent change noted in patients treated with IMRT. Further investigation is required to further elucidate the pathogenesis of PI-CRS and its relationship to post-RT dysbiosis, particularly IMPT.

Oral Candida in post-radiotherapy patients with xerostomia/hyposalivation: A narrative review

OBJECTIVE

Head and Neck Cancer (HNC) patients receiving radiotherapy (RT) often suffer from xerostomia and/or hyposalivation. As saliva plays an important antimicrobial and cleansing roles, these patients are at higher risks of opportunistic infections. This narrative review aims to provide an overview of current evidence on oral Candida colonisation and infection in these patients.

METHODS

A literature review of clinical studies on oral Candida colonisation and candidiasis in HNC patients receiving radiotherapy/chemoradiotherapy was conducted.

RESULTS

Many clinical studies found high levels of Candida colonisation and a substantial proportion of post-RT HNC patients suffering from oropharyngeal candidiasis (OPC). Importantly, oral Candida could be a reservoir for life-threatening systemic infection in immunocompromised patients. The rising prevalence of non-albicans Candida species and drug-resistant infections has made identification of Candida species and antifungal susceptibility more important. Recent advances in oral microbiome and its interactions with Candida are discussed. This review also offers perspectives on limitations of current evidence and suggestions for future research.

CONCLUSION

Further research to better understand Candida carriage, microbiome, OPC, and xerostomia/hyposalivation post-RT would aid in devising a more comprehensive long-term management plan and novel therapeutic approaches for HNC patients to achieve the full benefits of RT while minimising side effects.

Streptococcus salivarius K12 Alleviates Oral Mucositis in Patients Undergoing Radiotherapy for Malignant Head and Neck Tumors: A Randomized Controlled Trial

PURPOSE

Oral mucositis (OM) is a common debilitating toxicity associated with radiotherapy (RT) for malignant head and neck tumors. This prospective, randomized, double-blind, placebo-controlled trial aimed to evaluate the efficacy and safety of Streptococcus salivarius K12 (SsK12) in reducing the incidence, duration, and severity of severe OM (SOM).

METHODS

A total of 160 patients with malignant head and neck tumors undergoing definitive or postoperative adjuvant RT were randomly assigned (1:1) to receive SsK12 probiotic (n = 80) or placebo (n = 80) at West China Hospital, Sichuan University, Chengdu, China. Patients were instructed to suck SsK12 or placebo lozenges thrice daily from the initiation to the end of RT. OM was evaluated twice a week during RT and once a week thereafter for up to 8 weeks. The primary end point was the incidence of SOM. Adverse events were assessed according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0.

RESULTS

Baseline patient characteristics were similar in the SsK12 and placebo groups. The incidence of SOM was significantly lower in the SsK12 group as compared with the placebo group (36.6% v 54.2%; P = .0351). The duration (median, 0.0 days v 7.0 days; mean, 8.9 days v 18.3 days; P = .0084) and time to develop SOM (median, not estimable v 42.0 days; hazard ratio, 0.55 [95% CI, 0.34 to 0.89]; log-rank test: P = .0123) were also improved in the case of the SsK12 group. Adverse events were similar between the groups, and mild or moderate gastrointestinal reactions (flatulence or dyspepsia) associated with the lozenges were observed in two patients in the SsK12 group. High-throughput sequencing results indicated that SsK12 inhibited opportunistic pathogens and enriched oral commensals during RT.

CONCLUSION

In this prospective, randomized clinical trial, SsK12 probiotic significantly reduced the incidence, onset, and duration of SOM with a good safety profile.

Oral Health in Patients with History of Head and Neck Cancer: Complexity and Benefits of a Targeted Oral Healthcare Pathway

PURPOSE OF REVIEW

This work consists in a literature review on the current state of knowledge regarding the oral management of patients with a history of head and neck cancer (HNC), corroborated by clinical cases and illustrated by clear infographic summaries. It aims to provide healthcare professionals with a comprehensive overview of the oral health status of HCN patients.

RECENT FINDINGS

Head and neck cancers (HNCs) represent the seventh most common type of cancer worldwide, with over 660,000 annual new cases. Despite the significant negative impact of HNCs on oral health, patients often receive no or inappropriate oral care while the significant impact of oral pathologies on cancer prognosis is commonly underestimated. This work (i) describes the oral cavity during and after HNC through the prism of care complexity and (ii) highlights several potential key factors that could worsen long-time patients' prognosis and quality of life. By investigating the biological, microbiological, functional, and psychological dimensions of the interrelationships between HNCs and oral health, the authors explored the barriers and benefits of a targeted oral healthcare pathway. This article emphasizes the importance of multidisciplinary care and highlights the need for further research elucidating the intricate relationships between oral health and HNCs, particularly through the microbiota.

Radiation injury and gut microbiota-based treatment

The exposure to either medical sources or accidental radiation can cause varying degrees of radiation injury (RI). RI is a common disease involving multiple human body parts and organs, yet effective treatments are currently limited. Accumulating evidence suggests gut microbiota are closely associated with the development and prevention of various RI. This article summarizes 10 common types of RI and their possible mechanisms. It also highlights the changes and potential microbiota-based treatments for RI, including probiotics, metabolites, and microbiota transplantation. Additionally, a 5P-Framework is proposed to provide a comprehensive strategy for managing RI.

Influence of oral microbiome on longitudinal patterns of oral mucositis severity in patients with squamous cell carcinoma of the head and neck

BACKGROUND

This study investigated the influence of oral microbial features on the trajectory of oral mucositis (OM) in patients with squamous cell carcinoma of the head and neck.

METHODS

OM severity was assessed and buccal swabs were collected at baseline, at the initiation of cancer treatment, weekly during cancer treatment, at the termination of cancer treatment, and after cancer treatment termination. The oral microbiome was characterized via the 16S ribosomal RNA V4 region with the Illumina platform. Latent class mixed-model analysis was used to group individuals with similar trajectories of OM severity. Locally estimated scatterplot smoothing was used to fit an average trend within each group and to assess the association between the longitudinal OM scores and longitudinal microbial abundances.

RESULTS

Four latent groups (LGs) with differing patterns of OM severity were identified for 142 subjects. LG1 has an early onset of high OM scores. LGs 2 and 3 begin with relatively low OM scores until the eighth and 11th week, respectively. LG4 has generally flat OM scores. These LGs did not vary by treatment or clinical or demographic variables. Correlation analysis showed that the abundances of Bacteroidota, Proteobacteria, Bacteroidia, Gammaproteobacteria, Enterobacterales, Bacteroidales, Aerococcaceae, Prevotellaceae, Abiotrophia, and Prevotella_7 were positively correlated with OM severity across the four LGs. Negative correlation was observed with OM severity for a few microbial features: Abiotrophia and Aerococcaceae for LGs 2 and 3; Gammaproteobacteria and Proteobacteria for LGs 2, 3, and 4; and Enterobacterales for LGs 2 and 4.

CONCLUSIONS

These findings suggest the potential to personalize treatment for OM.

PLAIN LANGUAGE SUMMARY

Oral mucositis (OM) is a common and debilitating after effect for patients treated for squamous cell carcinoma of the head and neck. Trends in the abundance of specific microbial features may be associated with patterns of OM severity over time. Our findings suggest the potential to personalize treatment plans for OM via tailored microbiome interventions.

Implications of oral dysbiosis and HPV infection in head and neck cancer: from molecular and cellular mechanisms to early diagnosis and therapy

Head and neck cancer (HNC) is the sixth most common type of cancer, with more than half a million new cases annually. This review focuses on the role of oral dysbiosis and HPV infection in HNCs, presenting the involved taxons, molecular effectors and pathways, as well as the HPV-associated particularities of genetic and epigenetic changes and of the tumor microenvironment occurred in different stages of tumor development. Oral dysbiosis is associated with the evolution of HNCs, through multiple mechanisms such as inflammation, genotoxins release, modulation of the innate and acquired immune response, carcinogens and anticarcinogens production, generation of oxidative stress, induction of mutations. Thus, novel microbiome-derived biomarkers and interventions could significantly contribute to achieving the desideratum of personalized management of oncologic patients, regarding both early diagnosis and treatment. The results reported by different studies are not always congruent regarding the variations in the abundance of different taxons in HNCs. However, there is a consistent reporting of a higher abundance of Gram-negative species such as Fusobacterium, Leptotrichia, Treponema, Porphyromonas gingivalis, Prevotella, Bacteroidetes, Haemophilus, Veillonella, Pseudomonas, Enterobacterales, which are probably responsible of chronic inflammation and modulation of tumor microenvironment. Candida albicans is the dominant fungi found in oral carcinoma being also associated with shorter survival rate. Specific microbial signatures (e.g., F. nucleatum, Bacteroidetes and Peptostreptococcus) have been associated with later stages and larger tumor, suggesting their potential to be used as biomarkers for tumor stratification and prognosis. On the other hand, increased abundance of Corynebacterium, Kingella, Abiotrophia is associated with a reduced risk of HNC. Microbiome could also provide biomarkers for differentiating between oropharyngeal and hypopharyngeal cancers as well as between HPV-positive and HPV-negative tumors. Ongoing clinical trials aim to validate non-invasive tests for microbiome-derived biomarkers detection in oral and throat cancers, especially within high-risk populations. Oro-pharyngeal dysbiosis could also impact the HNCs therapy and associated side-effects of radiotherapy, chemotherapy, and immunotherapy. HPV-positive tumors harbor fewer mutations, as well as different DNA methylation pattern and tumor microenvironment. Therefore, elucidation of the molecular mechanisms by which oral microbiota and HPV infection influence the HNC initiation and progression, screening for HPV infection and vaccination against HPV, adopting a good oral hygiene, and preventing oral dysbiosis are important tools for advancing in the battle with this public health global challenge.

The Promise of Precision Nutrition for Modulation of the Gut Microbiota as a Novel Therapeutic Approach to Acute Graft-versus-host Disease

Acute graft-versus-host disease (aGVHD) is a severe side effect of allogeneic hematopoietic stem cell transplantation (aHSCT) that has complex phenotypes and often unpredictable outcomes. The current management is not always able to prevent aGVHD. A neglected actor in the management of aGVHD is the gut microbiota. Gut microbiota dysbiosis after aHSCT is caused by many factors and may contribute to the development of aGVHD. Diet and nutritional status modify the gut microbiota and a wide range of products are now available to manipulate the gut microbiota (pro-, pre-, and postbiotics). New investigations are testing the effect of probiotics and nutritional supplements in both animal models and human studies, with encouraging results. In this review, we summarize the most recent literature about the probiotics and nutritional factors able to modulate the gut microbiota and we discuss the future perspective in developing new integrative therapeutic approaches to reducing the risk of graft-versus-host disease in patients undergoing aHSCT.

Attempts to Understand Oral Mucositis in Head and Neck Cancer Patients through Omics Studies: A Narrative Review

Oral mucositis (OM) is a common and clinically impactful side effect of cytotoxic cancer treatment, particularly in patients with head and neck squamous cell carcinoma (HNSCC) who undergo radiotherapy with or without concomitant chemotherapy. The etiology and pathogenic mechanisms of OM are complex, multifaceted and elicit both direct and indirect damage to the mucosa. In this narrative review, we describe studies that use various omics methodologies (genomics, transcriptomics, microbiomics and metabolomics) in attempts to elucidate the biological pathways associated with the development or severity of OM. Integrating different omics into multi-omics approaches carries the potential to discover links among host factors (genomics), host responses (transcriptomics, metabolomics), and the local environment (microbiomics).

The Role of the Innate Immune Response in Oral Mucositis Pathogenesis

Oral mucositis (OM) is a significant complication of cancer therapy with limited management strategies. Whilst inflammation is a central feature of destructive and ultimately ulcerative pathology, to date, attempts to mitigate damage via this mechanism have proven limited. A relatively underexamined aspect of OM development is the contribution of elements of the innate immune system. In particular, the role played by barriers, pattern recognition systems, and microbial composition in early damage signaling requires further investigation. As such, this review highlights the innate immune response as a potential focus for research to better understand OM pathogenesis and development of interventions for patients treated with radiotherapy and chemotherapy. Future areas of evaluation include manipulation of microbial-mucosal interactions to alter cytotoxic sensitivity, use of germ-free models, and translation of innate immune-targeted agents interrogated for mucosal injury in other regions of the alimentary canal into OM-based clinical trials.

Oral microbiome characterization in oral mucositis patients-A systematic review

BACKGROUND

Oral mucositis (OM) is a severe and common adverse effect of cancer treatment. The oral microbiome appears to play a role on the onset and severity of OM. Therefore, this systematic review aims to characterize the oral dysbiosis associated with OM.

METHODS

The PRISMA checklist was followed and PubMed, Web of Science, and Scopus were screened for clinical studies characterizing the oral microbiome alterations in patients with OM.

RESULTS

From a total of 2500 articles retrieved, we included nine articles in this systematic review. Certain types of bacteria, as Fusobacterium, were recognized as predictors of the onset of OM. In addition, it was reported that patients with severe OM presented a reduction in alpha-diversity, an increase in beta-diversity. The abundance of some taxa significantly changed with OM severity, with Bacillota phylum and genera Leptotrichia, Actinomyces, and Prevotella decreasing and Treponema increasing with disease progression. Additionally, during cancer treatment, changes in the oral microbiome have been observed in OM patients, with an increase in Candida and nosocomial pathogens, including Staphylococcus species.

CONCLUSION

Our review indicates that cancer treatment can significantly alter the oral microbiome, with more pronounced changes observed in patients with severe OM in all relevant oral phyla, but more pronounced in Bacillota phylum.

Microbiome Analysis of Organic and Conventional Chickens Processed Using Whole Carcass Enrichment and Rinse Methods

Investigating the chicken microbiome is important to establish control measures for pathogens to protect consumers. This study aimed at evaluating the comparative efficiency of human pathogen detection through 16S rRNA sequencing of organic and conventional chickens processed using whole carcass enrichment (WCE) and rinse (WCR) methods. Organic and conventional whole broiler carcasses (n = 31) were vigorously shaken with 500 mL buffered peptone water (BPW). For the rinse method, a 30 mL aliquot was mixed with 30 mL of BPW. The rest of the sample, including the carcass, was used for the enrichment method. All samples were incubated at 37°C for 24 h. The samples were divided into five groups [Negative Control: only BPW without chicken (n = 5), Organic-Rinsed (n = 7), -Enriched (n = 8), Conventional-Rinsed (n = 7), and -Enriched (n = 9)]. Fifty milliliters of each sample were subjected to DNA extraction followed by 16S rRNA sequencing. Proteobacteria and Firmicutes predominated the microbiota of both conventional and organic chickens, followed by low abundances of Bacteroidetes and Fusobacterium. While the abundance of Proteobacteria and Firmicutes remained unchanged in organic chicken irrespective of the methods used, a noticeable shift in the Proteobacteria and Firmicutes ratio (59%:39% in rinsed to 38%:60% in enriched) was observed in conventional chicken. Furthermore, the choice of method did not yield any differences in Abundance-Based Coverage Estimator, and Jackknife, among conventional and organic chickens but resulted in a statistically significant difference in the Shannon, Simpson, Chao1, and phylogenetic diversity indices (p < 0.05). The relative abundance of Salmonella and Campylobacter was less than 0.1%. The results suggested the WCE method provides a broad range of information on the chicken microbiome.

Oral fungal profiling and risk of nasopharyngeal carcinoma: a population-based case-control study

BACKGROUND

Dysbiosis of the oral mycobiome has been linked to some diseases, including cancers. However, the role of oral fungal communities in nasopharyngeal carcinoma (NPC) carcinogenesis has not previously been investigated.

METHODS

We characterized the oral salivary fungal mycobiome in 476 untreated incident NPC patients and 537 population-based controls using fungal internal transcribed spacer (ITS)-2 sequencing. The relationship between oral fungal mycobiome and the risk of NPC was assessed through bioinformatic and biostatistical analyses.

FINDINGS

We found that lower fungal alpha diversity was associated with an increased odds of NPC [lower vs. higher: observed features (adjusted odds ratio [OR] = 5.81, 95% confidence interval [CI] = 3.60-9.38); Simpson diversity (1.53, 1.03-2.29); Shannon diversity (2.03, 1.35-3.04)]. We also observed a significant difference in global fungal community patterns between cases and controls based on Bray-Curtis dissimilarity (P < 0.001). Carriage of oral fungal species, specifically, Saccharomyces cerevisiae, Candida tropicalis, Lodderomyces elongisporus, Candida albicans, and Fusarium poae, was associated with significantly higher odds of NPC, with ORs ranging from 1.56 to 4.66. Individuals with both low fungal and low bacterial alpha diversity had a profoundly elevated risk of NPC.

INTERPRETATION

Our results suggest that dysbiosis in the oral mycobiome, characterized by a loss of fungal community diversity and overgrowth of several fungal organisms, is associated with a substantially increased risk of NPC.

FUNDING

This work was funded by the US National Institutes of Health, the Swedish Research Council, the High-level Talents Research Start-up Project of Fujian Medical University, and the China Scholarship Council.

Omega-3 nanoemulgel in prevention of radiation-induced oral mucositis and its associated effect on microbiome: a randomized clinical trial

BACKGROUND

Oral mucositis (OM) is recognized as one of the most frequent debilitating sequelae encountered by head and neck cancer (HNC) patients treated by radiotherapy. This results in severe mucosal tissue inflammation and oral ulcerations that interfere with patient's nutrition, quality of life (QoL) and survival. Omega-3 (ω-3) polyunsaturated fatty acids (PUFAs) have recently gained special interest in dealing with oral diseases owing to its anti-inflammatory, anti-oxidant and wound healing properties. Thus, this study aims to assess topical Omega-3 nanoemulgel efficacy in prevention of radiation-induced oral mucositis and regulation of oral microbial dysbiosis.

MATERIALS AND METHODS

Thirty-four head and neck cancer patients planned to receive radiotherapy were randomly allocated into two groups: Group I: conventional preventive treatment and Group II: topical Omega-3 nanoemulgel. Patients were evaluated at baseline, three and six weeks after treatment using the World Health Organization (WHO) grading system for oral mucositis severity, Visual Analogue Scale (VAS) for perceived pain severity, and MD-Anderson Symptom Inventory for Head and Neck cancer (MDASI-HN) for QoL. Oral swabs were collected to assess oral microbiome changes.

RESULTS

VAS scores and WHO mucositis grades were significantly lower after six weeks of treatment with topical Omega-3 nanoemulgel when compared to the conventional treatment. The total MDASI score was significantly higher in the control group after three weeks of treatment, and the head and neck subscale differed significantly at both three and six weeks. A significant reduction in Firmicutes/Bacteroidetes ratio was observed after six weeks in the test group indicating less microbial dysbiosis.

CONCLUSIONS

Topical Omega-3 nanoemulgel demonstrated a beneficial effect in prevention of radiation-induced oral mucositis with a possibility of regulating oral microbial dysbiosis.

Oral microbial changes and oral disease management before and after the treatment of hematological malignancies: a narrative review

OBJECTIVES

Patients with hematological malignancies have dynamic changes in oral microbial communities before and after treatment. This narrative review describes the changes in oral microbial composition and diversity, and discusses an oral microbe-oriented strategy for oral disease management.

MATERIALS AND METHODS

A literature search was performed in PubMed/Medline, Web of Science, and Embase for articles published between 1980 and 2022. Any articles on the changes in oral microbial communities in patients with hematological malignancies and their effects on disease progression and prognosis were included.

RESULTS

Oral sample detection and oral microbial sequencing analysis of patients with hematological malignancies showed a correlation between changes in oral microbial composition and diversity and disease progression and prognosis. The possible pathogenic mechanism of oral microbial disorders is the impairment of mucosal barrier function and microbial translocation. Probiotic strategies, antibiotic strategies, and professional oral care strategies targeting the oral microbiota can effectively reduce the risk of oral complications and the grade of severity in patients with hematological malignancies.

CLINICAL RELEVANCE

This review provides dentists and hematologists with a comprehensive understanding of the host-microbe associated with hematologic malignancies and oral disease management advice.

Influence of the microbiome on radiotherapy-induced oral mucositis and its management: A comprehensive review

Radiation-induced mucositis is the most common, debilitating and painful acute toxicity associated with active treatment in head and neck cancer area, severely affecting more than 65% of patients. Oral microbiota significantly changes during cancer therapy and appears to be involved on its pathophysiology. This review aims to present a comprehensive update of new etiopathogenic factors and treatments that may decrease the incidence of mucositis, mainly modifications of dietary interventions to modify microbiome. Despite advances in recent years, its management is mainly symptomatic opioid-based with variable results on different substances analyzed for its prevention. Immunonutrition seems to play a significant role, particularly the supplementation of compounds such as fatty acids, polyphenols or selected probiotics have shown to promote commensal bacteria diversity and reduced incidence of ulcerative mucositis. Modification of the microbiome is a promising preventive treatment for mucositis although its evidence is still scarce. Large studies are needed to demonstrate the efficacy of interventions on microbiome and its clinical impact on radiation-induced mucositis.

Symptom clusters after chemoradiotherapy in discharged nasopharyngeal carcinoma patients

Objective

To investigate the incidence of complications and types of chemoradiotherepy induces symptom clusters in patients with nasopharyngeal carcinoma (NPC) who were first diagnosed after treatment and discharged from hospital.

Methods

After their discharge home, 130 NPC patients who had been treated with chemoradiotherapy were asked to complete a modified Chinese version of the Quality of Life Questionnaire-Head and Neck Module developed by the European Organization for the Research and Treatment of Cancer in the Head and Neck. Symptom clusters in patients were identified through exploratory factor analysis.

Results

The most serious symptoms for discharged NPC patients who had received chemoradiotherapy were dental problems, a sense of obstruction while swallowing, embarrassment in physical contact with family members and friends, difficulty in speaking with others, and embarrassment in public. The six symptom clusters identified through exploratory factor analysis were (1) painful eating, (2) social difficulties, (3) psychological disorders, (4) symptomatic shame, (5) teeth/throat injuries, and (6) sensory abnormalities. The total contribution rate of variance was 65.73%.

Conclusion

NPC patients who are treated with chemoradiotherapy can experience adverse symptom clusters that continue after discharge. Nurses should evaluate the patients' symptoms before discharge and provide targeted health education services which would reduce the patients' complications and improve the quality of life at home. Besides, medical staff should evaluate the complications in a timely and comprehensive manner and provide individualized health education for the affected patients to help them manage chemoradiotherapy side effects.

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

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

From Pathogenesis to Intervention: The Importance of the Microbiome in Oral Mucositis

Oral mucositis (OM) is a common and impactful toxicity of standard cancer therapy, affecting up to 80% of patients. Its aetiology centres on the initial destruction of epithelial cells and the increase in inflammatory signals. These changes in the oral mucosa create a hostile environment for resident microbes, with oral infections co-occurring with OM, especially at sites of ulceration. Increasing evidence suggests that oral microbiome changes occur beyond opportunistic infection, with a growing appreciation for the potential role of the microbiome in OM development and severity. This review collects the latest articles indexed in the PubMed electronic database which analyse the bacterial shift through 16S rRNA gene sequencing methodology in cancer patients under treatment with oral mucositis. The aims are to assess whether changes in the oral and gut microbiome causally contribute to oral mucositis or if they are simply a consequence of the mucosal injury. Further, we explore the emerging role of a patient's microbial fingerprint in OM development and prediction. The maintenance of resident bacteria via microbial target therapy is under constant improvement and should be considered in the OM treatment.

Ascidian-Inspired Temperature-Switchable Hydrogels with Antioxidant Fullerenols for Protecting Radiation-Induced Oral Mucositis and Maintaining the Homeostasis of Oral Microbiota

A key characteristic of radiation-induced oral mucositis (RIOM) is oxidative stress mediated by the "reactive oxygen species (ROS) storm" generated from water radiolysis, resulting in severe pathological lesions, accompanied by a disturbance of oral microbiota. Therefore, a sprayable in situ hydrogel loaded with "free radical sponge" fullerenols (FOH) is developed as antioxidant agent for RIOM radioprotection. Inspired by marine organisms, 3,4,5-trihydroxyphenylalanine (TOPA) which is enriched in ascidians is grafted to clinically approved temperature-switchable Pluronic F127 to produce gallic acid (containing the TOPA fragment)-modified Pluronic F127 (MGA) hydrogels to resist the fast loss of FOH via biomimetic adhesion during oral movement and saliva erosion. Based on this, progressive RIOM found in mice is alleviated by treatment of FOH-loaded MGA hydrogels whether pre-irradiation prophylactic administration or post-irradiation therapeutic administration, which contributes to maintaining the homeostasis of oral microbiota. Mechanistically, FOH inhibits cell apoptosis by scavenging radiation-induced excess ROS and up-regulates the inherent enzymatic antioxidants, thereby protecting the proliferation and migration of mucosal epithelial cells. In conclusion, this work not only provides proof-of-principle evidence for the oral radioprotection of FOH by blocking the "ROS storm", but also provides an effective and easy-to-use hydrogel system for mucosal in situ administration.

Radiation Therapy and the Microbiome; More Than a Gut Feeling

ABSTRACT

It is increasingly recognized that heterogeneities in tumor response and severity of adverse effects in irradiated patients can be attributed to the tumor microenvironment and host-related factors. Among the latter, a growing body of literature in recent years has demonstrated the role of the patient's microbiome in modulating both tumor and normal tissue response to radiotherapy (RT). Upon contact with the environment after birth, the infant's gastrointestinal tract is rapidly colonized by microbiota, which is low in diversity and predominantly characterized by 2 dominant species, Actinobacteria and Proteobacteria. With time, intestinal microbiota diversity increases, and colonization of Firmicutes and Bacteroidetes becomes dominant. By the time a child reaches 3 years, the gut microbiota composition has been reshaped and is relatively similar to that of an adult. The microbiome colonizing the different body organs comprises various species and abundances, which may impact human health. Although the adult microbiome composition is thought to remain stable in health, microbiome diversity and composition respond to different environmental and pathological conditions, including pharmaceutical interventions and RT. Our review focuses on how the gut microbiota modulates normal tissue toxicity and tumor control. Readers who want to learn more about how RT shapes gut microbiome diversity and composition are referred to several excellent recently published reviews.

Oral Microbiota Alteration and Roles in Epstein-Barr Virus Reactivation in Nasopharyngeal Carcinoma

Microbiota has recently emerged as a critical factor associated with multiple malignancies. Nasopharyngeal carcinoma (NPC) is highly associated with Epstein-Barr virus (EBV); the oncovirus resides and is transmitted in the oral cavity. However, the alternation of oral microbiota in NPC patients and its potential link to EBV reactivation and host cell response under the simultaneous existence of EBV and specific bacteria is largely unknown. Here, oral microbiota profiles of 303 NPC patients and controls with detailed clinical information, including serum EBV anti-virus capsid antigen (VCA) IgA level, were conducted. A distinct microbial community with lower diversity and imbalanced composition in NPC patients was observed. Notably, among enriched bacteria in patients, Streptococcus sanguinis was associated with anti-VCA IgA, an indicator of NPC risk and EBV reactivation. By measuring the concentration of its metabolite, hydrogen peroxide (H2O2), in the saliva of clinical patients, we found the detection rate of H2O2 was 2-fold increased compared to healthy controls. Further coculture assay of EBV-positive Akata cells with bacteria in vitro showed that S. sanguinis induced EBV lytic activation by its metabolite, H2O2. Host and EBV whole genome-wide transcriptome sequencing and EBV methylation assays showed that H2O2 triggered the host cell signaling pathways, notably tumor necrosis factor alpha (TNF-α) via NF-κB, and induced the demethylation of the global EBV genome and the expression of EBV lytic-associated genes, which could result in an increase of virus particle release and potential favorable events toward tumorigenesis. In brief, our study identified a characterized oral microbial profile in NPC patients and established a robust link between specific oral microbial alteration and switch of latency to lytic EBV infection status in the oral cavity, which provides novel insights into EBV's productive cycle and might help to further clarify the etiology of NPC. IMPORTANCE EBV is classified as the group I human carcinogen and is associated with multiple cancers, including NPC. The interplays between the microbiota and oncovirus in cancer development remain largely unknown. In this study, we investigate the interactions between resident microbes and EBV coexistence in the oral cavity of NPC patients. We identify a distinct oral microbial feature for NPC patients. Among NPC-enriched bacteria, we illustrated that a specific species, S. sanguinis, associated with elevated anti-IgA VCA in patients, induced EBV lytic activation by its by-product, H2O2, and activated the TNF-α/NF-κB pathway of EBV-positive B cells in vitro, together with increased detection rate of H2O2 in patients' oral cavities, which strengthened the evidence of bacteria-virus-host interaction in physiological circumstances. The effects of imbalanced microbiota on the EBV latent-to-lytic switch in the oral cavity might create the likelihood of EBV infection in epithelial cells at the nasopharynx and help malignant transition and cancer development.

The Microbiome's Influence on Head and Neck Cancers

PURPOSE OF REVIEW

Head and neck tumors (HNC) rank sixth among cancers worldwide. Due to their late diagnosis and poor prognosis, they are a clinical challenge. However, recent years have seen a dynamic development of science on the microbiome. The aim of the study is to discuss the role of the microbiome in HNC, the impact of the microbiome on oncogenesis, the course of the disease, as well as on treatment, and its toxicity.

RECENT FINDINGS

The microbiome's influence on oncogenesis, the course of the disease, and the effectiveness of oncological treatment have been confirmed in cancers of the colon, pancreas, lungs, and prostate. There is no solid literature on HNC. Many studies indicate disruption of the oral microbiome and periodontal disease as potential cancer risk factors. Disruption of the microbiome increases radiotherapy's toxicity, intensifying radiation reactions. The microbiome plays an important role in cancer. It is a new target in research into new therapies. It may also be a prognostic marker of cancer development. Changes in the composition of the microbiome modulate the effectiveness of oncological treatment. More research is needed on the microbiome and its effects on HNC.

Predicting Nomogram for Severe Oral Mucositis in Patients with Nasopharyngeal Carcinoma during Intensity-Modulated Radiation Therapy: A Retrospective Cohort Study

BACKGROUND

Oral mucositis is an acute adverse reaction with high incidence during radiotherapy. Severe oral mucositis can seriously affect patients' quality of life and compliance with radiotherapy. The aim of this study was to identify the risk factors for severe oral mucositis and to develop a nomogram for predicting severe oral mucositis in patients with nasopharyngeal carcinoma.

METHODS

One hundred and ninety patients with nasopharyngeal carcinoma were retrospectively screened in this study. Least absolute shrinkage and selection operator regression and multivariate logistic regression analyses were performed to identify the best predictors of severe oral mucositis. A nomogram was constructed based on the factors. Finally, the discriminative ability of the nomogram was evaluated.

RESULTS

Four independent factors predicting severe oral mucositis were identified: age, N stage, the cycle of induction chemotherapy, and dose-volumetric parameter V40 (%) of oral cavity. The area under the receiver of operating characteristic curve of the nomogram was 0.759 (95% confidence interval: 0.691-0.827).

CONCLUSIONS

A predictive nomogram for severe oral mucositis was established and validated in this study. The nomogram provides a reliable and practical model for clinically predicting the probability of severe oral mucositis in patients with nasopharyngeal carcinoma before intensity-modulated radiation therapy.

Distinctive microbiota of delayed healing of oral mucositis after radiotherapy of nasopharyngeal carcinoma

Background

Oral mucositis is the most common complication after radiotherapy of nasopharyngeal carcinoma (NPC). Previous studies had revealed that oral microbiota took great alteration soon after and during radiotherapy. Here, we aimed to investigate if the alteration of oral microbiota was related to delayed healing of oral mucositis after six month of radiotherapy.

Methods

We recruited 64 NPC patients and collected samples after six month of radiotherapy. 32 patients were included into normal healing group (N), 22 patients were mild delayed healing group (M), while 10 patients were severe delayed healing group (S). 16S rRNA gene sequencing was used to assess and identify oral microbiota alteration.

Results

The diversity of oral microbial communities was not significantly different. Composition of oral microbial was huge different among S group, for the Actinobacteria and Veillonella were significantly increased, which showed significant dysbiosis of the oral microbiome. Functional analysis of metabolic pathways of oral microbiota demonstrated that degradation of organic acids and amino acids were significantly increased in S group. Moreover, phenotype analysis found that relative abundance of aerobic and biofilm formation were higher in S group. We also found the Actinobacteria co-occurred with Veillonellaceae, but anti-occurred with other biofilm oral bacteria. These two biomarkers may be predictable for severe delayed healing of oral mucositis after radiotherapy.

Conclusion

This study suggests a potential association between oral microbiome and delayed healing of oral mucositis. The Actinobacteria and Veillonellaceae may be biomarkers in predicting the risks for the severe delayed healing of oral mucositis after radiotherapy of NPC.

Effect of synbiotic mouthwash on oral mucositis induced by radiotherapy in oral cancer patients: a double-blind randomized clinical trial

PURPOSE

Considering the complex pathobiology of oral mucositis, especially in oral cancer patients, the prevention and treatment of oral mucositis in patients undergoing radiotherapy remains an essential and clinically crucial unmet need. The present study aims to investigate and compare the effects of synbiotic mouthwash with normal saline mouthwash on the prevention and control of radiotherapy-induced oral mucositis in oral cancer patients.

METHODS

Double-blind, randomized clinical trial (RCT) performed on 64 oral cancer patients who underwent radiotherapy (IRCT20201106049288N1, registration date: 2020-12-23). Patients were divided randomly into the case (32 subjects) and control (32 subjects) groups. All patients underwent intensity-modulated radiotherapy and received 6000 cGY of radiotherapy in 34 fractions. All patients received the usual treatment for mucositis, but in the case group, synbiotic mouthwash was prescribed and in the control group, normal saline mouthwash was prescribed from a day before the start to the end of radiotherapy treatment. Patients were monitored every session for 6 weeks to check the progression, oral involvement severity, and mucositis grade.

RESULTS

The case group showed a significant reduction in the oral mucositis severity. The mucositis grade in the case group from the 7th session of oral examination was significantly lower than the control (p < 0.05), and this significant difference persisted until the last session of oral examination. Incidence rates of severe oral mucositis (grade 3) during the treatment period were 11.59% in the case and 36.45% in control (p < 0.001).

CONCLUSION

Synbiotic mouthwash significantly reduces and prevents oral mucositis intensity in oral cancer patients undergoing radiotherapy.

The human oral - nasopharynx microbiome as a risk screening tool for nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a common head and neck cancer with a poor prognosis. There is an urgent need to develop a simple and convenient screening tool for early detection and risk screening of NPC. 139 microbial samples were collected from 40 healthy people and 39 patients with nasopharyngeal biopsy. A total of 40 and 39 oral, eight and 27 nasal cavity, nine and 16 nasopharyngeal microbial samples were collected from the two sets of individuals. A risk screening tool for NPC was established by 16S rDNA sequencing and random forest. Patients with nasopharyngeal biopsy had significantly lower nasal cavity and nasopharynx microbial diversities than healthy people. The beta diversity of the oral microbiome was significantly different between the two groups. The NPC screening tools based on nasopharyngeal and oral microbiomes have 88% and 77.2% accuracies, respectively. The nasopharyngeal biopsy patients had significantly higher Granulicatella abundance in their oral cavity and lower Pseudomonas and Acinetobacter in the nasopharynx than healthy people. This study established microbiome-based non-invasive, simple, no radiation, and low-cost NPC screening tools. Individuals at a high risk of NPC should be advised to seek further examination, which might improve the early detection of NPC and save public health costs.

The Crosstalk between Microbiome and Immunotherapeutics: Myth or Reality

The gut microbiome refers to microorganisms and their genetic material influencing local and systemic inflammation. Inflammation is known to contribute to cancer development, progression, and treatment. Evidence suggests that modulating the gut microbiome may affect responses to various cancer therapies. The gut microbiota has been suggested to have an impact on immunotherapy efficacy, especially the currently widely used immune checkpoint inhibitors in various malignancies. Microbial interventions like fecal microbiota transplantation, various probiotics, or even antibiotics can increase or decrease the tumor’s sensitivity to immunotherapy. However, not all tumors react in the same manner, highlighting the tumor microenvironment heterogeneity across tumor types and the influence this has on the crosstalk between the microbiome and therapy outcomes. In this study, we intend to review the association between the gut microbiota and immunotherapy response in cancer patients and the factors regulating this interaction.

The microbiota and radiotherapy for head and neck cancer: What should clinical oncologists know?

Radiotherapy is a linchpin in head and neck squamous cell carcinoma (HN-SCC) treatment. Modulating tumour and/or normal tissue biology offers opportunities to further develop HN-SCC radiotherapy. The microbiota, which can exhibit homeostatic properties and be a modulator of immunity, has recently received considerable interest from the Oncology community. Microbiota research in head and neck oncology has also flourished. However, available data are difficult to interpret for clinical and radiation oncologists. In this review, we focus on how microbiota research can contribute to the improvement of radiotherapy for HN-SCC, focusing on how current and future research can be translated back to the clinic. We include in-depth discussions about the microbiota, its multiple habitats and relevance to human physiology, mechanistic interactions with HN-SCC, available evidence on microbiota and HNC oncogenesis, efficacy and toxicity of treatment. We discuss clinically-relevant areas such as the role of the microbiota as a predictive and prognostic biomarker, as well as the potential of leveraging the microbiota and its interactions with immunity to improve treatment results. Importantly, we draw parallels with other cancers where research is more mature. We map out future directions of research and explain clinical implications in detail.

A Review of the Role of Oral Microbiome in the Development, Detection, and Management of Head and Neck Squamous Cell Cancers

The role of the microbiome in the development and propagation of head and neck squamous cell cancer (HNSCC) is largely unknown and the surrounding knowledge lags behind what has been discovered related to the microbiome and other malignancies. In this review, the authors performed a structured analysis of the available literature from several databases. The authors discuss the merits and detriments of several studies discussing the microbiome of the structures of the aerodigestive system throughout the development of HNSCC, the role of the microbiome in the development of malignancies (generally and in HNSCC) and clinical applications of the microbiome in HNSCC. Further studies will be needed to adequately describe the relationship between HNSCC and the microbiome, and to push this relationship into a space where it is clinically relevant outside of a research environment.

Changes in Oral Microbial Diversity in a Piglet Model of Traumatic Brain Injury

Dynamic changes in the oral microbiome have gained attention due to their potential diagnostic role in neurological diseases such as Alzheimer's disease and Parkinson's disease. Traumatic brain injury (TBI) is a leading cause of death and disability in the United States, but no studies have examined the changes in oral microbiome during the acute stage of TBI using a clinically translational pig model. Crossbred piglets (4-5 weeks old, male) underwent either a controlled cortical impact (TBI, n = 6) or sham surgery (sham, n = 6). The oral microbiome parameters were quantified from the upper and lower gingiva, both buccal mucosa, and floor of the mouth pre-surgery and 1, 3, and 7 days post-surgery (PS) using the 16S rRNA gene. Faith's phylogenetic diversity was significantly lower in the TBI piglets at 7 days PS compared to those of sham, and beta diversity at 1, 3, and 7 days PS was significantly different between TBI and sham piglets. However, no significant changes in the taxonomic composition of the oral microbiome were observed following TBI compared to sham. Further studies are needed to investigate the potential diagnostic role of the oral microbiome during the chronic stage of TBI with a larger number of subjects.

Precision medicine for risk prediction of oral complications of cancer therapy–The example of oral mucositis in patients receiving radiation therapy for cancers of the head and neck

Oral complications of cancer therapy are common, markedly symptomatic, negatively impact patients' quality of life, and add significantly to the cost of care. Patients' risk of treatment-related toxicities is not uniform; most patients suffer at least one side effect, while others tolerate treatment without any. Understanding those factors which impact risk provides opportunities to customize cancer treatment plans to optimize tumor kill and minimize regimen-related toxicities. Oral mucositis (OM) is an iconic example of a clinically significant and common complication of head and neck radiotherapy. Individuals' OM risk is governed by the cumulative impact of factors related to treatment, the tumor, and the patient. In addition to OM risk prediction, a second opportunity to apply precision medicine will evolve as viable treatment options become available. Patients vary widely in how well or poorly they respond to specific treatments. What works well in one individual, might fail in another. Prospective determination of the likelihood of a patient's response or non-response is based on a range of biological interactions. Coupled with risk determination, the application of precision medicine will allow caregivers, patients, and payers to integrate risk/benefit to optimize the probability that the best treatment is be given to the most appropriate patients.

Confounding factors in the assessment of oral mucositis in head and neck cancer

Treatment of locally advanced head and neck carcinoma not amenable for surgical resection or resected with high-risk features is usually based on (chemo-)radiation treatment. Oral mucositis represents one of the main side effects of (chemo-)radiation, with an important impact on quality of life and causing approximately 20% of early interruption of treatment, leading to a suboptimal dose administered. Treatment and prevention of oral mucositis have a central role in the therapeutic pathways of head and neck cancer patients but remains quite challenging. Although extensive research is conducted to identify interventions for the management of mucositis, very few interventions had sufficient evidence to generate an international expert consensus. This may be partially explained by confounding factors that could influence the development and assessment of oral mucositis. Little is known about the confounding factors of oral mucositis, which, if not well balanced in an experimental study, could lead to non-solid results. The current paper aims to review the main oral mucositis confounding factors related to head and neck cancer patients.

Proteomic and microbiota analyses of the oral cavity during psychological stress

Psychological stress is associated with various oral diseases such as aphthous stomatitis, oral lichen planus, taste disturbances and glossodynia. However, the underlying mechanism is still unknown. The aim of this study was to determine the effect of psychological stress on salivary proteins and the oral microbiota in a rat model of chronic restraint stress. Six-week-old Sprague Dawley rats were subjected to restraint stress for four hours daily for 1 month. The behavior, weights of the adrenal glands, and serum corticosterone levels were evaluated as stress markers. Proteomic analysis of the saliva was performed using two-dimensional gel electrophoresis followed by mass spectrometry and Western blotting. Analysis of the oral microbiota was performed via 16S rRNA next-generation sequencing. The low mean body weights, lower number of entries and time spent in the open arm of elevated plus maze, high adrenal gland/body weight ratios, and high serum corticosterone levels confirmed the high levels of stress in the stress group of rats compared to the controls. Thirty-three protein spots were found to be significantly altered between the two groups. After silver staining, seven visible spots were subjected for mass spectrometry, and the expression levels of the two most significantly altered proteins, BPI fold containing family A member 2 and von Ebner’s gland protein, were confirmed by Western blotting. 16S rRNA sequencing analysis revealed a significant reduction in alpha diversity in the stress group compared to the controls. The abundances of oral bacteria, such as Facklamia and Corynebacterium, were significantly altered between the two groups. Additionally, analysis with PICRUSt2 software predicted 37 different functional pathways to be altered between the groups. In conclusion, the present study identified altered salivary proteins and oral microbiota due to psychological stress. These findings might aid in understanding the pathogenesis of stress-related oral diseases.

Oral-Gut Microbiome Axis in the Pathogenesis of Cancer Treatment-Induced Oral Mucositis

Oral mucositis (OM) is one of the most common and debilitating oral complications of cancer treatments including chemotherapy, radiotherapy, and hematopoietic stem cell transplantation. It is associated with severe pain and difficulties in chewing, swallowing, and speech. This leads to impairment of basic oral functions and could result in unplanned treatment interruption or modification. As such, OM negatively impacts both patients' quality of life as well as tumor prognostic outcomes. Understanding pathways underlying OM pathogenesis help identify new targets for intervention or prevention. The pathophysiology of OM has been widely studied over past decades with several pathways related to oxidative stress, inflammation, and molecular and cellular signaling being implicated. In this mini-review, we will discuss the emerging role of the oral-gut microbiome axis in the development of OM. Particularly, we will elaborate on how the alterations in the oral and gut microbiota as well as intestinal dysfunction caused by cancer treatments could contribute to the pathogenesis of OM. Further, we will briefly discuss the potential methods for targeting the oral-gut microbiome axis to improve OM outcomes.

Influence of Pre-treatment Saliva Microbial Diversity and Composition on Nasopharyngeal Carcinoma Prognosis

Background

The human microbiome has been reported to mediate the response to anticancer therapies. However, research about the influence of the oral microbiome on nasopharyngeal carcinoma (NPC) survival is lacking. We aimed to explore the effect of oral microbiota on NPC prognosis.

Methods

Four hundred eighty-two population-based NPC cases in southern China between 2010 and 2013 were followed for survival, and their saliva samples were profiled using 16s rRNA sequencing. We analyzed associations of the oral microbiome diversity with mortality from all causes and NPC.

Results

Within- and between-community diversities of saliva were associated with mortality with an average of 5.29 years follow-up. Lower Faith’s phylogenetic diversity was related to higher all-cause mortality [adjusted hazard ratio (aHR), 1.52 (95% confidence interval (CI), 1.06–2.17)] and NPC-specific mortality [aHR, 1.57 (95% CI, 1.07–2.29)], compared with medium diversity, but higher phylogenetic diversity was not protective. The third principal coordinate (PC3) identified from principal coordinates analysis (PCoA) on Bray–Curtis distance was marginally associated with reduced all-cause mortality [aHR, 0.85 (95% CI, 0.73–1.00)], as was the first principal coordinate (PC1) from PCoA on weighted UniFrac [aHR, 0.86 (95% CI, 0.74–1.00)], but neither was associated with NPC-specific mortality. PC3 from robust principal components analysis was associated with lower all-cause and NPC-specific mortalities, with HRs of 0.72 (95% CI, 0.61–0.85) and 0.71 (95% CI, 0.60–0.85), respectively.

Conclusions

Oral microbiome may be an explanatory factor for NPC prognosis. Lower within-community diversity was associated with higher mortality, and certain measures of between-community diversity were related to mortality. Specifically, candidate bacteria were not related to mortality, suggesting that observed associations may be due to global patterns rather than particular pathogens.

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.

Perception of Pediatric Oncological Patients and Their Parents/Guardians about a Hospital Oral Health Program: A Qualitative Study

BACKGROUND

The oral healthcare offered to pediatric cancer patients at the hospital level must include educational and preventive strategies based on dialogical and welcoming professional attitudes. Therefore, the current study aimed to evaluate the perception of pediatric cancer patients and their parents/guardians about an educational and preventive oral healthcare program implemented in a reference hospital for cancer treatment.

METHODS

A qualitative follow-up investigation was conducted in which we evaluated the perception of pediatric cancer patients and their parents/guardians regarding an educational and preventive oral health program (OHEPP). The participants were 27 children and adolescents undergoing cancer treatment and their parents/guardians, and the assessment was carried out at 15 and 30 days after beginning the program through semi-structured interviews. The program used audiovisual resources, storytelling and playful instruments for the oral health education of patients and parents/guardians. The interviews were then transcribed and the Discourse of the Collective Speech (DCS) technique was performed for data analysis.

RESULTS

Patients and parents/guardians reported improvement in oral hygiene habits and conditions. Patients reported greater enthusiasm for oral care and highlighted the recreational aspect of the program. Parents/guardians reported being more clear about oral changes and paying attention to the appearance of comorbidities resulting from anticancer treatment.

CONCLUSIONS

This study suggests that implementation of the oral health program favored communication between health professionals, patients and their parents/guardians, expanding knowledge and generating behavior change in oral healthcare.

The Effect of Radiation and Chemoradiation Therapy on the Head and Neck Mucosal Microbiome: A Review

Radiation (RT) and chemoradiation therapy (CRT) play an essential role in head and neck cancer treatment. However, both cause numerous side effects in the oral cavity, paranasal sinuses, and pharynx, having deleterious consequences on patients’ quality of life. Concomitant with significant advances in radiation oncology, much attention has turned to understanding the role of the microbiome in the pathogenesis of treatment-induced tissue toxicity, to ultimately explore microbiome manipulation as a therapeutic intervention. This review sought to discuss current publications investigating the impact of RT and CRT-induced changes on the head and neck microbiome, using culture-independent molecular methods, and propose opportunities for future directions. Based on 13 studies derived from a MEDLINE, EMBASE, and Web of Science search on November 7, 2021, use of molecular methods has uncovered various phyla and genera in the head and neck microbiome, particularly the oral microbiome, not previously known using culture-based methods. However, limited research has investigated the impact of RT/CRT on subsites other than the oral cavity and none of the studies aimed to examine the relationship between the head and neck microbiome and treatment effectiveness. Findings from this review provide helpful insights on our current understanding of treatment-induced oral mucositis, dental plaque, and caries formation and highlight the need for future research to examine the effect of RT/CRT on the sinonasal and oropharyngeal microbiome. In addition, future research should use larger cohorts, examine the impact of the microbiome on treatment response, and study the effect of manipulating the microbiome to overcome therapy resistance.

Oral microbiota transplantation fights against head and neck radiotherapy-induced oral mucositis in mice

Oral mucositis is a common radiotherapy-induced complication among nasal, oral and laryngeal cancer (NOALC) patients. This complication leads to decreased quality of life and has few treatments. Here, fractionated radiation was performed to mimic radiotherapy for NOALCs in mouse models. Oral microbiota transplantation (OMT) mitigated oral mucositis, as judged by reconstructed epithelium and tongue papillae, fewer infiltrated leukocytes and more proliferative cells in the oral epithelium. The gut microbiota impacted oral mucositis progression, and OMT restructured oral and gut bacteria configurations and reprogrammed the gene expression profile of tongue tissues. In vivo silencing of glossal S100 calcium binding protein A9 debilitated the radioprotection of OMT. In light of clinical samples, we identified that patients with different alteration trends of Lactobacillaceae frequency presented different primary lesions and prognoses of NOALC following radiotherapy. Together, our findings provide new insights into the oral-gut microbiota axis and underpin the suggestion that OMT might be harnessed as a novel remedy to fight against oral mucositis in NOALC patients following radiotherapy in preclinical settings. Of note, oral microorganisms, such as Lactobacillaceae, might be employed as biomarkers to predict the prognosis of NOALC with radiotherapy.

Biological Bases of Immune-Related Adverse Events and Potential Crosslinks With Immunogenic Effects of Radiation

Immune checkpoint inhibitors have gained an established role in the treatment of different tumors. Indeed, their use has dramatically changed the landscape of cancer care, especially for tumor types traditionally known to have poor outcomes. However, stimulating anticancer immune responses may also elicit an unusual pattern of immune-related adverse events (irAEs), different from those of conventional chemotherapy, likely due to a self-tolerance impairment featuring the production of autoreactive lymphocytes and autoantibodies, or a non-specific autoinflammatory reaction. Ionizing radiation has proven to promote both positive pro-inflammatory and immunostimolatory activities, and negative anti-inflammatory and immunosuppressive mechanisms, as a result of cross-linked interactions among radiation dose, the tumor microenvironment and the host genetic predisposition. Several publications argue in favor of combining immunotherapy and a broad range of radiation schedules, based on the recent evidence of superior treatment responses and patient survival. The synergistic modulation of the immune response by radiation therapy and immunotherapeutics, particularly those manipulating T-cell activation, may also affect the type and severity of irAEs, suggesting a relationship between the positive antitumor and adverse autoimmune effects of these agents. As yet, information on factors that may help to predict immune toxicity is still lacking. The aim of our work is to provide an overview of the biological mechanisms underlying irAEs and possible crosslinks with radiation-induced anticancer immune responses. We believe such an overview may support the optimization of immunotherapy and radiotherapy as essential components of multimodal anticancer therapeutic approaches. Challenges in translating these to clinical practice are discussed.

The Potential Effect of Microbiota in Predicting The Freshness of Chilled Chicken

1. The goals of this study were to analyse the changes in microbiota composition of chilled chicken during storage and identify microbial biomarkers related to meat freshness.2. The study used 16S rDNA sequencing to track the microbiota shift in chilled chicken during storage. Associations between microbiota composition and storage time were analysed and microbial biomarkers were identified.3. The results showed that microbial diversity of chilled chicken decreased with the storage time. A total of 27 and 24 microbial biomarkers were identified by using orthogonal partial least squares (OPLS) and the random forest regression approach, respectively. The receiver operating characteristic (ROC) curve analysis indicated that the OPLS regression approach had better performance in identifying freshness-related biomarkers. The multiple stepwise regression analysis identified four key microbial biomarkers, including Streptococcus, Carnobacterium, Serratia and Photobacterium genera and constructed a predictive model.4. The study provided microbial biomarkers and a model related to the freshness of chilled chicken. These findings provide a basis for developing detection methods of the freshness of chilled chicken.