Crosstalk between the gut microbiome and clinical response in locally advanced thoracic esophageal squamous cell carcinoma during neoadjuvant camrelizumab and chemotherapy

Advancements in immunotherapy for advanced esophageal squamous cell carcinoma: a comprehensive review of current strategies and future directions

INTRODUCTION

Esophageal cancer (EC), particularly esophageal squamous cell carcinoma (ESCC), is characterized by high incidence and poor prognosis worldwide, necessitating novel therapeutic approaches like immunotherapy. This review explores the impact of immune checkpoint inhibitors (ICIs) on ESCC, especially focusing on PD-1/PD-L1 and CTLA-4 inhibitors. Our literature search, conducted across databases including PubMed, Web of Science, and EMBASE, from January 2010 to December 2023, aimed at identifying advancements, challenges, and future directions in the use of immunotherapy for ESCC.

AREAS COVERED

We provide a detailed analysis of clinical trials evaluating the efficacy of ICIs as monotherapy and in combination with chemotherapy, radiotherapy, and targeted therapy for locally advanced ESCC. Our findings highlight the significant survival benefits offered by ICIs, albeit with varying efficacy across patient populations, emphasizing the need for precise biomarkers to tailor treatment strategies.

EXPERT OPINION

The integration of immunotherapy into the ESCC treatment paradigm represents a significant shift, improving survival outcomes. Future research should focus on optimizing combination therapies and novel immunotherapeutic agents, incorporating genetic and tumor microenvironment analyses to enhance patient selection and treatment efficacy.

Pathological response to neoadjuvant chemoradiotherapy for oesophageal squamous cell carcinoma in Eastern versus Western countries: meta-analysis

OBJECTIVE

Locally advanced oesophageal squamous cell carcinoma can be treated with neoadjuvant chemoradiotherapy or chemotherapy followed by oesophagectomy. Discrepancies in pathological response rates have been reported between studies from Eastern versus Western countries. The aim of this study was to compare the pathological response to neoadjuvant chemoradiotherapy in Eastern versus Western countries.

METHODS

Databases were searched until November 2022 for studies reporting pCR rates after neoadjuvant chemoradiotherapy for oesophageal squamous cell carcinoma. Multi-level meta-analyses were performed to pool pCR rates separately for cohorts from studies performed in centres in the Sinosphere (East) or in Europe and the Anglosphere (West).

RESULTS

For neoadjuvant chemoradiotherapy, 51 Eastern cohorts (5636 patients) and 20 Western cohorts (3039 patients) were included. Studies from Eastern countries included more men, younger patients, more proximal tumours, and more cT4 and cN+ disease. Patients in the West were more often treated with high-dose radiotherapy, whereas patients in the East were more often treated with a platinum + fluoropyrimidine regimen. The pooled pCR rate after neoadjuvant chemoradiotherapy was 31.7% (95% c.i. 29.5% to 34.1%) in Eastern cohorts versus 40.4% (95% c.i. 35.0% to 45.9%) in Western cohorts (fixed-effect P = 0.003). For cohorts with similar cTNM stages, pooled pCR rates for the East and the West were 32.5% and 41.9% respectively (fixed-effect P = 0.003).

CONCLUSION

The pathological response to neoadjuvant chemoradiotherapy is less favourable in patients treated in Eastern countries compared with Western countries. Despite efforts to investigate accounting factors, the discrepancy in pCR rate cannot be entirely explained by differences in patient, tumour, or treatment characteristics.

Stachyose in combination with L. rhamnosus GG ameliorates acute hypobaric hypoxia-induced intestinal barrier dysfunction through alleviating inflammatory response and oxidative stress

High altitude is closely related to intestinal mucosal damage and intestinal microbiota imbalance, and there is currently no effective prevention and treatment measures. In this study, the effects of stachyose (STA), L. rhamnosus GG (LGG) and their combination on inflammatory response, oxidatve stress and intestinal barrier function in mice exposed to acute hypobaric hypoxia were investigated. Our results indicated the combination of STA and LGG could more effectively regulate intestinal microbiota disorders caused by hypobaric hypoxia than STA or LGG alone. When mice were administered with STA + LGG, the content of short chain fatty acids (SCFAs) especially butyric acid significantly increased, which helped intestinal cells to form tight connections, improve the level of anti-inflammatory cytokine (TGF-β) and antioxidant enzymes (SOD, CAT, GSH-Px), and decrease the expression of pro-inlammatory cytokines and hypoxia-inducing factors (IFN-γ, IL-1β, IL-6, TNF-α and HIF-1α), thereby enhance the strong intestinal barrier function. Furthermore, the synbiotics significantly reduced the ratio of Firmicutes to Bacteroidetes, while significantly increased the relative abundance of Rikenella, Bacteroides, Odoribacter, Ruminiclostridium_5 and Gordonibacter, which were correlated with production of SCFAs and anti-inflammatory role. Correlation analysis showed that the protective effect of synbiotics on intestinal barrier function was associated with its anti-inflammatory activity and antioxidant capacity. It provided a strong foundation for further research on the role of STA and LGG in maintaining normal intestinal function at high altitude. Our study has identified and demonstrated a new synbiotic that may be one of the ideal intervention measures for preventing and treating intestinal dysfunction at high altitude.

Current and future on definitive concurrent chemoradiotherapy for inoperable locally advanced esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is an aggressive and fatal disease that is usually diagnosed when the chances for surgical intervention has been missed. Definitive concurrent chemoradiotherapy (dCRT) is the first choice of treatment for inoperable locally advanced esophageal squamous cell carcinoma (LA-ESCC). Nevertheless, the local recurrence rate for esophageal cancer patients undergoing dCRT remains high at 40-60%, with a 5-year overall survival rate of solely 10-30%. Immunotherapy in combination with dCRT is a promising treatment for inoperable LA-ESCC, for that improved long-term survival is expected. The present review provides a comprehensive overview of the evolutionary trajectory of dCRT for LA-ESCC, delineates notable relevant clinical studies, addresses unresolved concerns regarding the combination of dCRT with immunotherapy, and highlights promising directions for future research. When dCRT is combined with immunotherapy, the following aspects should be carefully explored in the future studies, including the optimal irradiation dose, segmentation scheme, radiotherapy technique, timing, sequence and duration of radiotherapy, and the selection of chemotherapeutic and immunologic drugs. In addition, further investigations on the mechanisms of how dCRT combined with immunotherapy exerts synergistic anti-tumor effects and molecular biomarkers ensuring precise screening of ESCC patients are needed.

Effectiveness and safety of camrelizumab-containing neoadjuvant therapy in patients with esophageal squamous cell carcinoma: a prospective multicenter observational cohort study

Background

Camrelizumab has been demonstrated to be a feasible treatment option for locally advanced esophageal squamous cell carcinoma (ESCC) when combined with neoadjuvant chemotherapy. This trial was conducted to investigate the effectiveness and safety of camrelizumab-containing neoadjuvant therapy in patients with ESCC in daily practice.

Methods

This prospective multicenter observational cohort study was conducted at 13 tertiary hospitals in Southeast China. Patients with histologically or cytologically confirmed ESCC [clinical tumor-node-metastasis (cTNM) stage I-IVA] who had received at least one dose of camrelizumab-containing neoadjuvant therapy were eligible for inclusion.

Results

Between June 1, 2020 and July 13, 2022, 255 patients were enrolled and included. The median age was 64 (range, 27 to 82) years. Most participants were male (82.0%) and had clinical stage III-IVA diseases (82.4%). A total of 169 (66.3%) participants underwent surgical resection; 146 (86.4%) achieved R0 resection, and 36 (21.3%) achieved pathological complete response (pCR). Grades 3-5 adverse events (AEs) were experienced by 14.5% of participants. Reactive cutaneous capillary endothelial proliferation occurred in 100 (39.2%) of participants and all were grade 1 or 2.

Conclusions

Camrelizumab-containing neoadjuvant therapy has acceptable effectiveness and safety profiles in real-life ESCC patients.

Correlation Between Microbial Community and Hatching Failure in Loggerhead Sea Turtle Caretta caretta

Microbial communities provide essential information about host ecology and could be helpful as a tool to improve species conservation efforts. However, microbes can also infect and compromise the host development process and viability. Caretta caretta is the most widespread marine turtle species in the Mediterranean basin and is the only species of sea turtle nesting along the Italian coasts. Little is known about the microbiota composition of the nest of sea turtles and its correlation with hatching failures. In this study, the microbial composition of two nests of C. caretta featuring different rates of hatching success from a nesting beach in Lampedusa (Italy) was analyzed and compared. The bacterial community was determined using culture-dependent methods and next-generation sequencing based on 16S rRNA gene metabarcoding analysis. Our results showed five dominant bacterial phyla (Proteobacteria, Bacteroidetes, Actinobacteria, Verrucomicrobia, and Firmicutes) and indicated different bacterial families (Pseudomonadaceae and Brucellaceae) as likely causes of hatching failures. Besides, our findings demonstrated the nests' active role in modulating the sand's bacterial communities. This study suggests microbiological analysis could be a valuable tool in monitoring nests to take preventive actions and reduce hatching failures.

Role of gut microbiome in cancer immunotherapy: from predictive biomarker to therapeutic target

Immunotherapy has emerged as an effective treatment for various types of cancers. Recent studies have highlighted a significant correlation between the gut microbiome and patients' response to immunotherapy. Several characteristics of the gut microbiome, such as community structures, taxonomic compositions, and molecular functions, have been identified as crucial biomarkers for predicting immunotherapy response and immune-related adverse events (irAEs). Unlike other -omics, the gut microbiome can serve as not only biomarkers but also potential targets for enhancing the efficacy of immunotherapy. Approaches for modulating the gut microbiome include probiotics/prebiotics supplementation, dietary interventions, fecal microbiota transplantation (FMT), and antibiotic administration. This review primarily focuses on elucidating the potential role of the gut microbiome in predicting the response to cancer immunotherapy and improving its efficacy. Notably, we explore reasons behind inconsistent findings observed in different studies, and highlight the underlying benefits of antibiotics in liver cancer immunotherapy.

Potential role of gut microbes in the efficacy and toxicity of immune checkpoints inhibitors

In recent years, Immune checkpoint inhibitors have been extensively used in the treatment of a variety of cancers. However, the response rates ranging from 13% to 69% depending on the tumor type and the emergence of immune-related adverse events have posed significant challenges for clinical treatment. As a key environmental factor, gut microbes have a variety of important physiological functions such as regulating intestinal nutrient metabolism, promoting intestinal mucosal renewal, and maintaining intestinal mucosal immune activity. A growing number of studies have revealed that gut microbes further influence the anticancer effects of tumor patients through modulation of the efficacy and toxicity of immune checkpoint inhibitors. Currently, faecal microbiota transplantation (FMT) have been developed relatively mature and suggested as an important regulator in order to enhance the efficacy of treatment. This review is dedicated to exploring the impact of differences in flora composition on the efficacy and toxicity of immune checkpoint inhibitors as well as to summarizing the current progress of FMT.

Radiotherapy combined with immune checkpoint inhibitors in locally advanced/metastatic esophageal squamous cell carcinoma: clinical trials, efficacy and future directions

Esophageal squamous cell carcinoma (ESCC) is a common malignancy worldwide and often diagnosed at advanced stages with poor prognosis. Combination of radiotherapy and immunotherapy seems to be a promising approach for treating ESCC. This comprehensive review article summarizes the current state of combination of radiotherapy and immunotherapy in locally advanced/metastatic ESCC, delineates the clinical trials that merit attention, and outlines unresolved issues and future research directions in this field. The clinical trial findings suggest that radio-immunotherapy combination may improve tumor response and overall survival with manageable side effects, highlighting the importance of patient selection and the necessity for further research to optimize treatment strategies. Issues such as irradiation dosage, fractionation regimen, irradiation site and technique of radiotherapy, as well as the timing, sequence and duration of combination therapy will all affect treatment outcomes, justifying further in-depth investigation.

Evaluation of neoadjuvant immunotherapy and traditional neoadjuvant therapy for resectable esophageal cancer: a systematic review and single-arm and network meta-analysis

Objective

This systematic review and meta-analysis aimed to investigate the role of neoadjuvant immunochemotherapy with or without radiotherapy [NIC(R)T] compared to traditional neoadjuvant therapies, without immunotherapy [NC(R)T].

Summary background data

NCRT followed by surgical resection is recommended for patients with early-stage esophageal cancer. However, it is uncertain whether adding immunotherapy to preoperative neoadjuvant therapy would improve patient outcomes when radical surgery is performed following neoadjuvant therapy.

Methods

We searched PubMed, Web of Science, Embase, and Cochrane Central databases, as well as international conference abstracts. Outcomes included R0, pathological complete response (pCR), major pathological response (mPR), overall survival (OS) and disease-free survival (DFS) rates.

Results

We included data from 5,034 patients from 86 studies published between 2019 and 2022. We found no significant differences between NICRT and NCRT in pCR or mPR rates. Both were better than NICT, with NCT showing the lowest response rate. Neoadjuvant immunotherapy has a significant advantage over traditional neoadjuvant therapy in terms of 1-year OS and DFS, with NICT having better outcomes than any of the other three treatments. There were no significant differences among the four neoadjuvant treatments in terms of R0 rates.

Conclusions

Among the four neoadjuvant treatment modalities, NICRT and NCRT had the highest pCR and mPR rates. There were no significant differences in the R0 rates among the four treatments. Adding immunotherapy to neoadjuvant therapy improved 1-year OS and DFS, with NICT having the highest rates compared to the other three modalities.

Systematic Review Registration

https://inplasy.com/inplasy-2022-12-0060/, identifier INPLASY2022120060.

Evaluation of the Oesophagogastric Cancer-Associated Microbiome: A Systematic Review and Quality Assessment

OBJECTIVE

Oesophagogastric cancer is the fifth most common cancer worldwide, with poor survival outcomes. The role of bacteria in the pathogenesis of oesophagogastric cancer remains poorly understood.

DESIGN

A systematic search identified studies assessing the oesophagogastric cancer microbiome. The primary outcome was to identify bacterial enrichment specific to oesophagogastric cancer. Secondary outcomes included appraisal of the methodology, diagnostic performance of cancer bacteria and the relationship between oral and tissue microbiome.

RESULTS

A total of 9295 articles were identified, and 87 studies were selected for analysis. Five genera were enriched in gastric cancer: Lactobacillus, Streptococcus, Prevotella, Fusobacterium and Veillonella. No clear trends were observed in oesophageal adenocarcinoma. Streptococcus, Prevotella and Fusobacterium were abundant in oesophageal squamous cell carcinoma. Functional analysis supports the role of immune cells, localised inflammation and cancer-specific pathways mediating carcinogenesis. STORMS reporting assessment identified experimental deficiencies, considering batch effects and sources of contamination prevalent in low-biomass samples.

CONCLUSIONS

Functional analysis of cancer pathways can infer tumorigenesis within the cancer-microbe-immune axis. There is evidence that study design, experimental protocols and analytical techniques could be improved to achieve more accurate and representative results. Whole-genome sequencing is recommended to identify key metabolic and functional capabilities of candidate bacteria biomarkers.

Efficacy and safety of neoadjuvant immunotherapy combined with chemoradiotherapy or chemotherapy in esophageal cancer: A systematic review and meta-analysis

Background

Significant progress has been made in the investigation of neoadjuvant immune-chemoradiotherapy (NICRT) and neoadjuvant immune-chemotherapy (NICT) on the outcomes of esophageal cancer patients. To summarize the current developments, a systematic review and meta-analysis were conducted to evaluate the efficacy and safety of neoadjuvant immunotherapy combined with chemoradiotherapy or chemotherapy.

Methods

A search strategy of prospective studies on esophageal cancer receiving neoadjuvant immunotherapy was predefined to scan PubMed, Embase, Cochrane, and additional major conferences for prospective studies. Efficacy was assessed by pathological complete response (pCR), major pathological response (MPR), and R0 resection rates. Safety was evaluated based on the incidence of grade ≥ 3 treatment-related adverse events (TRAEs), neoadjuvant therapy completion rate, surgical resection rate, and surgical delay rate. Differences between the NICRT and NICT groups were also analyzed.

Results

A total of 38 studies qualified for the analysis. The pooled pCR, MPR, and R0 resection rates were 30, 58, and 99%, respectively. The pCR and MPR in the NICRT vs. NICT group were 38% vs. 28% (p=0.078) and 67% vs. 57% (p=0.181), respectively. The pooled incidence of grade ≥ 3 TRAEs was 24% (NICRT,58%, I² = 61% vs. NICT,18%, I² = 79%; p<0.001). In addition, the pooled neoadjuvant therapy completion and surgical resection rates were 92% and 85%, respectively; the difference was not statistically significant between the NICRT and NICT groups.

Conclusions

Neoadjuvant immunotherapy combined with chemoradiotherapy or chemotherapy is effective and safe in the short term for locally advanced esophageal cancer. However, further randomized trials are needed to confirm which combined model is more favorable.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021284266, identifier CRD42021284266.