Effect of Antibiotic Use on Outcomes with Systemic Therapies in Metastatic Renal Cell Carcinoma

The microbiota and renal cell carcinoma

Renal cell carcinoma (RCC) accounts for about 2% of cancer diagnoses and deaths worldwide. Recent studies emphasized the critical involvement of microbial populations in RCC from oncogenesis, tumor growth, and response to anticancer therapy. Microorganisms have been shown to be involved in various renal physiological and pathological processes by influencing the immune system function, metabolism of the host and pharmaceutical reactions. These findings have extended our understanding and provided more possibilities for the diagnostic or therapeutic development of microbiota, which could function as screening, prognostic, and predictive biomarkers, or be manipulated to prevent RCC progression, boost anticancer drug efficacy and lessen the side effects of therapy. This review aims to present an overview of the roles of microbiota in RCC, including pertinent mechanisms in microbiota-related carcinogenesis, the potential use of the microbiota as RCC biomarkers, and the possibility of modifying the microbiota for RCC prevention or treatment. According to these scientific findings, the clinical translation of microbiota is expected to improve the diagnosis and treatment of RCC.

Influence of Microbiota on Tumor Immunotherapy

The role of the microbiome in immunotherapy has recently garnered substantial attention, with molecular studies and clinical trials providing emerging evidence on the pivotal influence of the microbiota in enhancing therapeutic outcomes via immune response modulation. However, the impact of microbial communities can considerably vary across individuals and different immunotherapeutic approaches, posing prominent challenges in harnessing their potential. In this comprehensive review, we outline the current research applications in tumor immunotherapy and delve into the possible mechanisms through which immune function is influenced by microbial communities in various body sites, encompassing those in the gut, extraintestinal barrier, and intratumoral environment. Furthermore, we discuss the effects of diverse microbiome-based strategies, including probiotics, prebiotics, fecal microbiota transplantation, and the targeted modulation of specific microbial taxa, and antibiotic treatments on cancer immunotherapy. All these strategies potentially have a profound impact on immunotherapy and pave the way for personalized therapeutic approaches and predictive biomarkers.

Association of antibiotic treatment with survival outcomes in treatment-naïve melanoma patients receiving immune checkpoint blockade

PURPOSE

The interaction of gut microbiome and immune system is being studied with increasing interest. Disturbing factors, such as antibiotics may impact the immune system via gut and interfere with tumor response to immune checkpoint blockade (ICB).

METHODS

In this multicenter retrospective cohort study exclusively treatment-naïve patients with cutaneous or mucosal melanoma treated with first-line anti-PD-1 based ICB for advanced, non-resectable disease between 06/2013 and 09/2018 were included. Progression-free (PFS), and overall survival (OS) according to antibiotic exposure (within 60 days prior to ICB and after the start of ICB vs. no antibiotic exposure) were analyzed. To account for immortal time bias, data from patients with antibiotics during ICB were analyzed separately in the time periods before and after start of antibiotics.

RESULTS

Among 578 patients with first-line anti-PD1 based ICB, 7% of patients received antibiotics within 60 days prior to ICB and 19% after starting ICB. Antibiotic exposure prior to ICB was associated with worse PFS (adjusted HR 1.75 [95% CI 1.22-2.52]) and OS (adjusted HR 1.64 [95% CI 1.04-2.58]) by multivariate analysis adjusting for potential confounders. The use of antibiotics after the start of ICB had no effect on either PFS (adjusted HR 1.19; 95% CI 0.89-1.60) or OS (adjusted HR 1.08; 95% CI 0.75-1.57).

CONCLUSIONS

Antibiotic exposure within 60 days prior to ICB seems to be associated with worse PFS and OS in melanoma patients receiving first-line anti-PD1 based therapy, whereas antibiotics after the start of ICB do not appear to affect PFS or OS.

Gut microbiota and immunotherapy of renal cell carcinoma

The gut microbiome has recently been proposed as a key player in cancer development and progression. Several studies have reported that the composition of the gut microbiome plays a role in the response to immune checkpoint inhibitors (ICIs). The gut microbiome modulation has been investigated as a potential therapeutic strategy for cancer, mainly in patients undergoing therapy with ICIs. In particular, modulation through probiotics, FMT or other microbiome-related approaches have proven effective to improve the response to ICIs. In this review, we examine the role of the gut microbiome in enhancing clinical responses to ICIs in the treatment of renal cancer.

What if amoxicillin/clavulanic acid reduces the cisplatin anticancer impact on oral cancer treatment?

Antibiotics-chemotherapeutics combination have become on the table for many cancer treatments. For this reason, we thought that further progress and development of studies to support chemotherapeutic approaches with the use of antibiotics may be beneficial in the clinical field. Cell lines (SCC-15, HTB-41, and MRC-5) were treated with 5-100 μM/ml concentrations of cisplatin (cisp) and amoxicillin/clavulanic acid (amx/cla) with combination (amx/cla-cisp) and alone in three different incubation periods. The all-cells viability was examined with WST-1 and apoptotic activity of the drugs were investigated via cell death ELISA assay kit. The cytotoxic impact of the 100 μM amx/cla-cisp combination was found to be reduced by up to 21.8%, which was significant given that the cytotoxic effect of only cisplatin therapy was 86.1%. Because our findings demonstrated that solo amx/cla therapy have almost no impact on proliferation or death, we focused on the amx/cla-cisp combination effect. It was found that the amx/cla-cisp combination has reduced the apoptotic fragment when comparing with the solely cisp-treated cells. Due to amx/cla-cisp combination on both cells but significantly on SCC-15 recovered the sole cisplatin effect, we believe that there might be a second thought when prescribing antibiotics while treating cancer patients. Not only the antibiotic's type but also the cancer type might interact to lessen the chemotherapeutic agent's impact which is clinically a dilemma to focus on.

From mucosal infection to successful cancer immunotherapy

The clinical management of advanced malignancies of the upper and lower urinary tract has been revolutionized with the advent of immune checkpoint blockers (ICBs). ICBs reinstate or bolster pre-existing immune responses while creating new T cell specificities. Immunogenic cancers, which tend to benefit more from immunotherapy than cold tumours, harbour tumour-specific neoantigens, often associated with a high tumour mutational burden, as well as CD8+ T cell infiltrates and ectopic lymphoid structures. The identification of beneficial non-self tumour antigens and natural adjuvants is the focus of current investigation. Moreover, growing evidence suggests that urinary or intestinal commensals, BCG and uropathogenic Escherichia coli influence long-term responses in patients with kidney or bladder cancer treated with ICBs. Bacteria infecting urothelium could be a prominent target for T follicular helper cells and B cells, linking innate and cognate CD8+ memory responses. In the urinary tract, commensal flora differ between healthy and tumoural mucosae. Although antibiotics can affect the prognosis of urinary tract malignancies, bacteria can have a major influence on cancer immunosurveillance. Beyond their role as biomarkers, immune responses against uropathogenic commensals could be harnessed for the design of future immunoadjuvants that can be advantageously combined with ICBs.

The impact of the gut microbiome on tumor immunotherapy: from mechanism to application strategies

Immunotherapy is one of the fastest developing areas in the field of oncology. Many immunological treatment strategies for refractory tumors have been approved and marketed. Nevertheless, much clinical and preclinical experimental evidence has shown that the efficacy of immunotherapy in tumor treatment varies markedly among individuals. The commensal microbiome mainly colonizes the intestinal lumen in humans, is affected by a variety of factors and exhibits individual variation. Moreover, the gut is considered the largest immune organ of the body due to its influence on the immune system. In the last few decades, with the development of next-generation sequencing (NGS) techniques and in-depth research, the view that the gut microbiota intervenes in antitumor immunotherapy through the immune system has been gradually confirmed. Here, we review important studies published in recent years focusing on the influences of microbiota on immune system and the progression of malignancy. Furthermore, we discuss the mechanism by which microbiota affect tumor immunotherapy, including immune checkpoint blockade (ICB) and adoptive T-cell therapy (ACT), and strategies for modulating the microbial composition to facilitate the antitumor immune response. Finally, opportunity and some challenges are mentioned to enable a more systematic understanding of tumor treatment in the future and promote basic research and clinical application in related fields.

Emerging resistance vs. losing response to immune check point inhibitors in renal cell carcinoma: two differing phenomena

The introduction of immune checkpoint inhibitor (ICI) has revolutionized the treatment of metastatic renal cell carcinoma (mRCC) and has dramatically improved the outcomes of patients. The use of monotherapy or combinations of ICIs targeting PD-1/PD-L1 and CTLA-4, as well as the addition of ICIs with tyrosine kinase inhibitors, has significantly enhanced the overall survival of mRCC patients. Despite these promising results, there remains a subset of patients who either do not respond to treatment (primary resistance) or develop resistance to therapy over time (acquired resistance). Understanding the mechanisms underlying the development of resistance to ICI treatment is crucial in the management of mRCC, as they can be used to identify new targets for innovative therapeutic strategies. Currently, there is an unmet need to develop new predictive and prognostic biomarkers that can aid in the development of personalized treatment options for mRCC patients. In this review, we summarize several mechanisms of ICI resistance in RCC, including alterations in tumor microenvironment, upregulation of alternative immune checkpoint pathways, and genetic and epigenetic changes. Additionally, we highlight potential strategies that can be used to overcome resistance, such as combination therapy, targeted therapy, and immune modulation.

Tyrosine kinase and immune checkpoints inhibitors in favorable risk metastatic renal cell carcinoma: Trick or treat?

Over the past decade, the management of metastatic renal cell carcinoma (RCC) has undergone rapid evolution, culminating in a significant improvement in prognosis with frontline immunotherapy. RCC is a highly immunogenic and pro-angiogenic cancer, and mounting evidence has established the immunosuppressive effects of pro-angiogenic factors on the host's immune system. Anti-angiogenic agents such as tyrosine kinase inhibitors (TKIs) and bevacizumab, which obstruct the vascular endothelial growth factor pathway, have demonstrated the potential to enhance antitumor activity and improve the efficacy of immune checkpoint inhibitors (ICIs). Consequently, various combinations of TKIs and ICIs have been assessed and are currently considered the preferred regimens for all metastatic RCC patients, regardless of their prognostic risk score. Nevertheless, some inquiries have arisen within the medical community, as metastatic RCC patients with favorable risk scores who received ICIs and TKIs in combination showed no statistically significant advantage in overall survival compared to those treated with sunitinib alone. Considering these concerns, this review aims to elucidate the rationale behind TKI and ICI combination therapies, provide a summary of current first-line metastatic RCC combinations approved for use, with a focus on favorable-risk patients, and outline present challenges and future perspectives in this context.

Mechanisms and clinical implications in renal carcinoma resistance: narrative review of immune checkpoint inhibitors

Clear cell renal cell carcinoma (ccRCC) is the most common histological subtype of renal cell carcinoma. The prognosis for patients with ccRCC has improved over recent years with the use of combination therapies with an anti-programmed death-1 (PD-1) backbone. This has enhanced the quality of life and life expectancy of patients with this disease. Unfortunately, not all patients benefit; eventually, most patients will develop resistance to therapy and progress. Recent molecular, biochemical, and immunological research has extensively researched anti-angiogenic and immune-based treatment resistance mechanisms. This analysis offers an overview of the principles underpinning the resistance pathways related to immune checkpoint inhibitors (ICIs). Additionally, novel approaches to overcome resistance that may be considered for the trial context are discussed.

Gut and urinary microbiota: the causes and potential treatment measures of renal cell carcinoma

Mounting evidence suggests that the gut microbiota plays a crucial role in the development and treatment of various cancers. Recent research on the urinary microbiota challenges the long-standing belief that urine is sterile, as urinary microbiota has been implicated in the development of bladder and prostate cancers, similar to the role of gut microbiota in cancer development. Although the precise involvement of microbiota in the proliferation and differentiation of renal cell carcinoma (RCC) remains unclear, dysbiosis is considered one possible mechanism by which microbiota may contribute to RCC development and treatment. This review summarizes potential mechanisms by which gut microbiota may contribute to the development of RCC, and provides evidence for the involvement of urinary microbiota in RCC. We also explore the role of gut microbiota in RCC treatment and propose that the composition of gut microbiota could serve as a predictive marker for the potential efficacy of immune checkpoint inhibitors (ICIs) in RCC patients. Additionally, evidence suggests that modulating the abundance and distribution of microbiota can enhance the therapeutic effects of drugs, suggesting that microbiota may serve as a promising adjuvant therapy for RCC. Overall, we believe that further investigation into the gut and urinary microbiome of RCC patients could yield valuable insights and strategies for the prevention and personalized treatment of RCC.

Biological Biomarkers of Response and Resistance to Immune Checkpoint Inhibitors in Renal Cell Carcinoma

Renal cell carcinoma (RCC) represents around 2% of cancer-related deaths worldwide per year. RCC is an immunogenic malignancy, and treatment of metastatic RCC (mRCC) has greatly improved since the advent of the new immunotherapy agents, including immune checkpoint inhibitors (ICIs). However, it should be stressed that a large proportion of patients does not respond to these therapies. There is thus an urgent need to identify predictive biomarkers of efficacy or resistance associated with ICIs or ICI/Tyrosine kinase inhibitor (TKI) combinations; this is a major challenge to achieve precision medicine for mRCC in routine practice. To identify potential biomarkers, it is necessary to improve our knowledge on the biology of immune checkpoints. A lot of efforts have been made over the last decade in the field of immuno-oncology. We summarize here the main data obtained in this field when considering mRCC. As for clinical biomarkers, clinician and scientific experts of the domain are facing difficulties in identifying such molecular entities, probably due to the complexity of immuno-oncology and the constant adaptation of tumor cells to their changing environment.

The gut dysbiosis-cancer axis: illuminating novel insights and implications for clinical practice

The human intestinal microbiota, also known as the gut microbiota, comprises more than 100 trillion organisms, mainly bacteria. This number exceeds the host body cells by a factor of ten. The gastrointestinal tract, which houses 60%-80% of the host's immune cells, is one of the largest immune organs. It maintains systemic immune homeostasis in the face of constant bacterial challenges. The gut microbiota has evolved with the host, and its symbiotic state with the host's gut epithelium is a testament to this co-evolution. However, certain microbial subpopulations may expand during pathological interventions, disrupting the delicate species-level microbial equilibrium and triggering inflammation and tumorigenesis. This review highlights the impact of gut microbiota dysbiosis on the development and progression of certain types of cancers and discusses the potential for developing new therapeutic strategies against cancer by manipulating the gut microbiota. By interacting with the host microbiota, we may be able to enhance the effectiveness of anticancer therapies and open new avenues for improving patient outcomes.

Association between antibiotics and adverse oncological outcomes in patients receiving targeted or immune-based therapy for hepatocellular carcinoma

Background & Aims

Immune checkpoint inhibitors (ICIs) alone or in combination with other ICIs or vascular endothelial growth factor pathway inhibitors are therapeutic options in unresectable/metastatic hepatocellular carcinoma (HCC). Whether antibiotic (ATB) exposure affects outcome remains unclear.

Methods

This study retrospectively analysed an FDA database including 4,098 patients receiving ICI (n = 842) either as monotherapy (n = 258) or in combination (n = 584), tyrosine kinase inhibitor (TKI) (n = 1,968), vascular endothelial growth factor pathway inhibitors (n = 480), or placebo (n = 808) as part of nine international clinical trials. Exposure to ATB within 30 days before or after treatment initiation was correlated with overall survival (OS) and progression-free survival (PFS) across therapeutic modality before and after inverse probability of treatment weighting (IPTW).

Results

Of 4,098 patients with unresectable/metastatic HCC, of which 39% were of hepatitis B aetiology and 21% were of hepatitis C aetiology, 83% were males with a median age of 64 years (range 18-88), a European Collaborative Oncology Group performance status of 0 (60%), and Child-Pugh A class (98%). Overall, ATB exposure (n = 620, 15%) was associated with shorter median PFS (3.6 months in ATB-exposed vs. 4.2 months; hazard ratio [HR] 1.29; 95% CI 1.22, 1.36) and OS (8.7 months in ATB-exposed vs. 10.6 months; HR 1.36; 95% CI 1.29, 1.43). In IPTW analyses, ATB was associated with shorter PFS in patients treated with ICI (HR 1.52; 95% CI 1.34, 1.73), TKI (HR 1.29; 95% CI 1.19, 1.39), and placebo (HR 1.23; 95% CI 1.11, 1.37). Similar results were observed in IPTW analyses of OS in patients treated with ICI (HR 1.22; 95% CI 1.08, 1.38), TKI (HR 1.40; 95% CI 1.30, 1.52), and placebo (HR 1.40; 95% CI 1.25, 1.57).

Conclusions

Unlike other malignancies where the detrimental effect of ATB may be more prominent in ICI recipients, ATB is associated with worse outcomes in this study across different therapies for HCC including placebo. Whether ATB is causally linked to worse outcomes through disruption of the gut-liver axis remains to be demonstrated in translational studies.

Impact and Implications

A growing body of evidence suggests the host microbiome, frequently altered by antibiotic treatment, as an important outcome predictor in the context of immune checkpoint inhibitor therapy. In this study, we analysed the effects of early antibiotic exposure on outcomes in almost 4,100 patients with hepatocellular carcinoma treated within nine multicentre clinical trials. Interestingly, early exposure to antibiotic treatment was associated with worse outcomes not only in patients treated with immune checkpoint inhibitors but also in those treated with tyrosine kinase inhibitors and placebo. This is in contrast to data published in other malignancies, where the detrimental effect of antibiotic treatment may be more prominent in immune checkpoint inhibitor recipients, highlighting the uniqueness of hepatocellular carcinoma given the complex interplay between cirrhosis, cancer, risk of infection, and the pleiotropic effect of molecular therapies for this disease.

A New Treatment Landscape for RCC: Association of the Human Microbiome with Improved Outcomes in RCC

Microbes play different roles in metabolism, local or systemic inflammation, and immunity, and the human microbiome in tumor microenvironment (TME) is important for modulating the response to immunotherapy in cancer patients. Renal cell carcinoma (RCC) is an immunogenic tumor, and immunotherapy is the backbone of its treatment. Correlations between the microbiome and responsiveness to immune checkpoint inhibitors have been reported. This review summarizes the recent therapeutic strategies for RCC and the effects of TME on the systemic therapy of RCC. The current understanding and advances in microbiome research and the relationship between the microbiome and the response to immunotherapy for RCC are also discussed. Improving our understanding of the role of the microbiome in RCC treatment will facilitate the development of microbiome targeting therapies to modify the tumor microbiome and improve treatment outcomes.

Defining the Role of the Gut Microbiome in the Pathogenesis and Treatment of Lymphoid Malignancies

The gut microbiome is increasingly being recognized as an important immunologic environment, with direct links to the host immune system. The scale of the gut microbiome's genomic repertoire extends the capacity of its host's genome by providing additional metabolic output, and the close communication between gut microbiota and mucosal immune cells provides a continued opportunity for immune education. The relationship between the gut microbiome and the host immune system has important implications for oncologic disease, including lymphoma, a malignancy derived from within the immune system itself. In this review, we explore past and recent discoveries describing the role that bacterial populations play in lymphomagenesis, diagnosis, and therapy. We highlight key relationships within the gut microbiome-immune-oncology axis that present exciting opportunities for directed interventions intended to shape the microbiome for therapeutic effect. We conclude with a limited summary of active clinical trials targeting the microbiome in hematologic malignancies, along with future directions on gut microbiome investigations within lymphoid malignancies.

The crosstalk between the gut microbiota and tumor immunity: Implications for cancer progression and treatment outcomes

The gastrointestinal tract is inhabited by trillions of commensal microorganisms that constitute the gut microbiota. As a main metabolic organ, the gut microbiota has co-evolved in a symbiotic relationship with its host, contributing to physiological homeostasis. Recent advances have provided mechanistic insights into the dual role of the gut microbiota in cancer pathogenesis. Particularly, compelling evidence indicates that the gut microbiota exerts regulatory effects on the host immune system to fight against cancer development. Some microbiota-derived metabolites have been suggested as potential activators of antitumor immunity. On the contrary, the disequilibrium of intestinal microbial communities, a condition termed dysbiosis, can induce cancer development. The altered gut microbiota reprograms the hostile tumor microenvironment (TME), thus allowing cancer cells to avoid immunosurvelliance. Furthermore, the gut microbiota has been associated with the effects and complications of cancer therapy given its prominent immunoregulatory properties. Therapeutic measures that aim to manipulate the interplay between the gut microbiota and tumor immunity may bring new breakthroughs in cancer treatment. Herein, we provide a comprehensive update on the evidence for the implication of the gut microbiota in immune-oncology and discuss the fundamental mechanisms underlying the influence of intestinal microbial communities on systemic cancer therapy, in order to provide important clues toward improving treatment outcomes in cancer patients.

Intratumoral bacteria are an important "accomplice" in tumor development and metastasis

As emerging tumor components, intratumoral bacteria have been found in many solid tumors. Several studies have demonstrated that different cancer subtypes have distinct microbial compositions, and mechanistic studies have shown that intratumoral bacteria may promote cancer initiation and progression through DNA damage, epigenetic modification, inflammatory responses, modulation of host immunity and activation of oncogenes or oncogenic pathways. Moreover, intratumoral bacteria have been shown to modulate tumor metastasis and chemotherapy response. A better understanding of the tumor microenvironment and its associated microbiota will facilitate the design of new metabolically engineered species, opening up a new era of intratumoral bacteria-based cancer therapy. However, many questions remain to be resolved, such as where intratumoral bacteria originate and whether there is a direct causal relationship between intratumoral bacteria and tumor susceptibility. In addition, suitable preclinical models and more advanced detection techniques are crucial for studying the biological functions of intratumoral bacteria. In this review, we summarize the complicated role of intratumoral bacteria in the regulation of cancer development and metastasis and discuss their carcinogenic mechanisms and potential therapeutic aspects.

A systematic review and meta-analysis evaluating the impact of antibiotic use on the clinical outcomes of cancer patients treated with immune checkpoint inhibitors

Background

Immune checkpoint inhibitors (ICIs) have considerably improved patient outcomes in various cancer types, but their efficacy remains poorly predictable among patients. The intestinal microbiome, whose balance and composition can be significantly altered by antibiotic use, has recently emerged as a factor that may modulate ICI efficacy. The objective of this systematic review and meta-analysis is to investigate the impact of antibiotics on the clinical outcomes of cancer patients treated with ICIs.

Methods

PubMed and major oncology conference proceedings were systematically searched to identify all studies reporting associations between antibiotic use and at least one of the following endpoints: Overall Survival (OS), Progression-Free Survival (PFS), Objective Response Rate (ORR) and Progressive Disease (PD) Rate. Pooled Hazard Ratios (HRs) for OS and PFS, and pooled Odds Ratios (ORs) for ORR and PD were calculated. Subgroup analyses on survival outcomes were also performed to investigate the potential differential effect of antibiotics according to cancer types and antibiotic exposure time windows.

Results

107 articles reporting data for 123 independent cohorts were included, representing a total of 41,663 patients among whom 11,785 (28%) received antibiotics around ICI initiation. The pooled HRs for OS and PFS were respectively of 1.61 [95% Confidence Interval (CI) 1.48-1.76] and 1.45 [95% CI 1.32-1.60], confirming that antibiotic use was significantly associated with shorter survival. This negative association was observed consistently across all cancer types for OS and depending on the cancer type for PFS. The loss of survival was particularly strong when antibiotics were received shortly before or after ICI initiation. The pooled ORs for ORR and PD were respectively of 0.59 [95% CI 0.47-0.76] and 1.86 [95% CI 1.41-2.46], suggesting that antibiotic use was significantly associated with worse treatment-related outcomes.

Conclusion

As it is not ethically feasible to conduct interventional, randomized, controlled trials in which antibiotics would be administered to cancer patients treated with ICIs to demonstrate their deleterious impact versus control, prospective observational studies and interventional trials involving microbiome modifiers are crucially needed to uncover the role of microbiome and improve patient outcomes. Such studies will reduce the existing publication bias by allowing analyses on more homogeneous populations, especially in terms of treatments received, which is not possible at this stage given the current state of the field. In the meantime, antibiotic prescription should be cautiously considered in cancer patients receiving ICIs.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42019145675.

The negative effect of antibiotics on RCC patients with immunotherapy: A systematic review and meta-analysis

Background

Microbiome dysbiosis is considered a predictive biomarker of clinical response in renal cell carcinoma (RCC), which can be regulated by antibiotics (ATB). Multiple studies have shown that concomitant ATB administration has inhibitory effects on immunotherapy in RCC. This review aimed to assess the impact of ATB on patient survival and tumor response in RCC with immunotherapy.

Methods

Literature evaluating the effect of ATB on immunotherapy in RCC from Cochrane Library^®, PubMed^®, Embase^®, Scopus^®, and Web of Science^® were systematically searched. Hazard ratios (HR) for progression-free survival (PFS) and overall survival (OS), odds ratio (OR) for objective response rate (ORR) and primary progressive disease (PD) were pooled as effect sizes for clinical outcomes. Subgroup analysis was conducted to reveal the determinants of the effect of ATB on immunotherapy, including time windows of ATB exposure to immunotherapy initiation, ICIs treatment and study location. The leave-one-out approach was adopted to analyze the heterogeneity formulated. Cumulative meta-analysis adding by time was used to observe dynamic changes of the results.

Results

Ten studies were included in the systematic review and six studies (with n=1,104 patients) were included in the meta-analysis, four studies were excluded for overlapping patients with subsequent larger studies and lack of unique patient-level data. ATB administration was significantly correlated with shorter PFS (HR=2.10, 95%CI [1.54; 2.85], I² = 2% after omitting study Derosa et al, 2021 detected by leave-one-out approach), shorter OS (HR=1.69, 95%CI [1.34; 2.12], I² = 25%) and worse ORR (OR=0.58, 95%CI [0.41; 0.84]), but no difference was observed in risk of PD (OR=1.18, 95%CI [0.97; 1.44]). No significant differences existed among the subgroups for determining the determinants of ATB inhibition.

Conclusions

Concomitant ATB with immunotherapy was associated with worse PFS, OS and ORR in RCC. No publication bias was observed in this study.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=349577, identifier CRD42022349577.

The role of gut microbiome in immune modulation in metastatic renal cell carcinoma

Treatment of metastatic renal cell carcinomas (mRCC) has drastically improved since the advent of immunotherapy with immune checkpoint inhibitors (ICIs), with a significant proportion of patients achieving durable responses. While this has revolutionized treatment and improved outcomes for mRCC patients, a large subset of patients still does not respond to treatment with ICIs. Moreover, ICIs can induce various immune-related adverse events, limiting their use in many patients. Therefore, there is a need to identify the predictive biomarkers of both efficacy and toxicity associated with ICIs, which would allow for a more personalized approach and help with clinical decision-making. This review aims to explore the role of the gut microbiome in RCC to overcome primary resistance and predict response to treatment with ICIs. First, current therapeutic strategies and mechanisms of action of ICI therapies for RCC treatment will be reviewed. With the technological development of shotgun whole-genome sequencing, the gut microbiome has emerged as an exciting field of research within oncology. Thus, the role of the microbiome and its bidirectional interaction with ICIs and other drugs will be explored, with a particular focus on the microbiome profile in RCC. Lastly, the rationale for future clinical interventions to overcome resistance to ICIs using fecal microbiota transplantation in patients with RCC will be presented.

Next Wave of Targets in the Treatment of Advanced Renal Cell Carcinoma

While surgical resection has remained the mainstay of treatment in early-stage renal cell carcinoma (RCC), therapeutic options in the advanced setting have remarkably expanded over the last 20 years. Tyrosine kinase inhibitors targeting the vascular endothelial growth factor receptor (VEGF-TKIs) and anti-programmed cell death 1 (PD-1)/anti-programmed death-ligand 1 (PD-L1)-based immune checkpoint inhibitors (ICIs) have become globally accepted options in the upfront metastatic setting, with different ICI-based combination strategies improving overall survival compared to single-agent Sunitinib. Although some patients benefit from long-term responses, most eventually develop disease progression. Ongoing efforts to better understand the biology of RCC and the different mechanisms of acquired resistance have led to the identification of promising therapeutic targets. Belzutifan, a novel agent targeting the angiogenic pathway involving hypoxia-inducible factors (HIFs), has already been approved for the treatment of early-stage tumors associated with VHL disease and represents a very promising therapy in advanced RCC. Other putative targets include epigenetic regulation enzymes, as well as several metabolites such as adenosine, glutaminase and tryptophan, which are critical players in cancer cell metabolism and in the tumor microenvironment. Different methods of immune regulation are also being investigated, including CAR-T cell therapy and modulation of the gut microbiome, in addition to novel agents targeting the interleukin-2 (IL-2) pathway. This review aims to highlight the emergent novel therapies for RCC and their respective completed and ongoing clinical trials.

The impact of antibiotic use on clinical features and survival outcomes of cancer patients treated with immune checkpoint inhibitors

Background

Nowadays, immune checkpoint inhibitors (ICIs) have become one of the essential immunotherapies for cancer patients. However, the impact of antibiotic (ATB) use on cancer patients treated with ICIs remains controversial.

Methods

Our research included retrospective studies and a randomized clinical trial (RCT) with cancer patients treated with ICIs and ATB, from the public database of PubMed, Web of Science, Embase, Cochrane, clinical trials, and JAMA. The survival outcomes included progression-free survival (PFS) and overall survival (OS). Meanwhile, hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated, and subgroup analyses were performed to determine the concrete association between ATB use and the prognosis of cancer patients treated in ICIs.

Results

Our results revealed that ATB use was associated with poor survival outcomes, including OS (HR: 1.94, 95% CI: 1.68–2.25, p <0.001) and PFS (HR: 1.83, 95% CI: 1.53–2.19, p <0.001). The subgroup analysis learned about the association between ATB use and the prognosis of cancer patients with ICI treatment, including 5 cancer types, 3 kinds of ICI, 5 different ATP windows, broad-spectrum ATB class, and ECOG score. ATB treatment was associated with poor OS of non-small-cell lung cancer (NSCLC), renal cell carcinoma (RCC), esophageal cancer (EC), and melanoma (MEL) in patients treated in ICIs, while non-small-cell lung cancer (NSCLC) and renal cell carcinoma (RCC) were associated with poor PFS. Meanwhile, it was strongly related to the ICI type and ATB window. Furthermore, it is firstly mentioned that the use of broad-spectrum ATB class was strongly associated with poor PFS.

Conclusion

In conclusion, our meta-analysis indicated that ATB use was significantly associated with poor OS and PFS of cancer patients treated with ICI immunotherapy, especially for patients with ATB use in the period of (−60 days; +30 days) near the initiation of ICI treatment. Also, different cancer types and the ICI type can also impact the survival outcome. This first reveals the strong relationship between the broad-spectrum ATB class and poor PFS. Still, more studies are needed for further study.

Gut microbiota influence immunotherapy responses: mechanisms and therapeutic strategies

The gut microbiota have long been recognized to play a key role in human health and disease. Currently, several lines of evidence from preclinical to clinical research have gradually established that the gut microbiota can modulate antitumor immunity and affect the efficacy of cancer immunotherapies, especially immune checkpoint inhibitors (ICIs). Deciphering the underlying mechanisms reveals that the gut microbiota reprogram the immunity of the tumor microenvironment (TME) by engaging innate and/or adaptive immune cells. Notably, one of the primary modes by which the gut microbiota modulate antitumor immunity is by means of metabolites, which are small molecules that could spread from their initial location of the gut and impact local and systemic antitumor immune response to promote ICI efficiency. Mechanistic exploration provides novel insights for developing rational microbiota-based therapeutic strategies by manipulating gut microbiota, such as fecal microbiota transplantation (FMT), probiotics, engineered microbiomes, and specific microbial metabolites, to augment the efficacy of ICI and advance the age utilization of microbiota precision medicine.

C-reactive protein flare predicts response to anti-PD-(L)1 immune checkpoint blockade in metastatic urothelial carcinoma

PURPOSE

Robust biomarkers to predict response to immune checkpoint blockade (ICB) in metastatic urothelial carcinoma (mUC) are still in demand. Recently, early C-reactive protein (CRP) kinetics and especially the novel CRP flare-response phenomenon has been associated with immunotherapy response.

METHODS

We conducted a multicentre observational study comprising 154 patients with mUC treated with ICB to evaluate the predictive value of a previously described on-treatment CRP kinetics: CRP flare responders (at least doubling of baseline CRP within the first month after initiation of ICB followed by a decline below baseline within three months), CRP responders (decline in baseline CRP by ≥ 30% within three months without a prior flare) and the remaining patients as CRP non-responders. CRP kinetics groups were correlated with baseline parameters, PD-L1 status, progression-free survival (PFS) and overall survival (OS).

RESULTS

Objective response was observed in 57.1% of CRP responders, 45.8% of CRP flare responders and 17.9% of CRP non-responders (P < 0.001). CRP flare response was associated with prolonged PFS and OS (P < 0.001). In multivariable Cox regression analysis, CRP flare responders showed a risk reduction of ∼70% for tumour progression and death compared to CRP non-responders. Subgroup analysis of CRP flare responders revealed that patients with a long-flare response (completed flare-response kinetics ≥6 weeks on-treatment) showed even more favourable outcomes following ICB (HR = 0.18, 95%-CI: 0.07-0.48, P < 0.001).

CONCLUSION

CRP (flare)response robustly predicts immunotherapy response and outcomes in mUC independent of PD-L1 status. Thus, early on-treatment CRP kinetics is a promising low-cost and easy-to-implement biomarker to optimise therapy monitoring in patients with mUC treated with ICB.

Effects of Concomitant Antibiotics Use on Immune Checkpoint Inhibitor Efficacy in Cancer Patients

Objective

Immune checkpoint inhibitors (ICIs) have changed the outcomes of a variety of cancers in an unprecedented manner. Gut microbiome plays a crucial regulatory role in the antineoplastic therapy of ICIs, which can be influenced by antibiotic (ABX) administration. In this efficacy evaluation, we aimed to clarify the correlations of ABX administration with the survival of cancer patients receiving ICIs treatment.

Method

The eligible literatures were searched using PubMed, Cochrane Library, Web of Science, and Clinical trials.gov databases before Nov 2021. The correlations of ABX administration with progression-free survival (PFS) and overall survival (OS) were determined using Hazard ratios (HRs) coupled with 95% confidence intervals (CIs).

Results

A total of 12 studies enrolling 6010 cancer patients receiving ICIs treatment were included in this efficacy evaluation. ABX administration was significantly correlated worse PFS (HR=1.60, 95%CI=1.33-1.92, P<0.00001) and OS (HR=1.46, 95%CI=1.32-1.61, P<0.00001). Similar results were found in the subgroup analysis of non-small cell lung cancer (NSCLC), renal cell carcinoma (RCC) and melanoma.

Conclusions

ABX use during ICIs treatment of cancer may significantly shorten PFS and OS. ABX should be used cautiously in cancer patients receiving ICIs. However, further validations are still essential due to existing publication bias.

The Emerging Role of the Gut Microbiome in the Cancer Response to Immune Checkpoint Inhibitors: A Narrative Review

The discovery of immune checkpoint inhibitors (ICIs) has revolutionized the care of cancer patients. However, the response to ICI therapy exhibits substantial interindividual variability. Efforts have been directed to identify biomarkers that predict the clinical response to ICIs. In recent years, the gut microbiome has emerged as a critical player that influences the efficacy of immunotherapy. An increasing number of studies have suggested that the baseline composition of a patient's gut microbiota and its dysbiosis are correlated with the outcome of cancer immunotherapy. This review tackles the rapidly growing body of evidence evaluating the relationship between the gut microbiome and the response to ICI therapy. Additionally, this review highlights the impact of antibiotic-induced dysbiosis on ICI efficacy and discusses the possible therapeutic interventions to optimize the gut microbiota composition to augment immunotherapy efficacy.

Risk Factors for Infections, Antibiotic Therapy, and Its Impact on Cancer Therapy Outcomes for Patients with Solid Tumors

Infections represent a significant cause of morbidity and mortality in cancer patients. Multiple factors related to the patient, tumor, and cancer therapy can affect the risk of infection in patients with solid tumors. A thorough understanding of such factors can aid in the identification of patients with substantial risk of infection, allowing medical practitioners to tailor therapy and apply prophylactic measures to avoid serious complications. The use of novel treatment modalities, including targeted therapy and immunotherapy, brings diagnostic and therapeutic challenges into the management of infections in cancer patients. A growing body of evidence suggests that antibiotic therapy can modulate both toxicity and antitumor response induced by chemotherapy, radiotherapy, and especially immunotherapy. This article provides a comprehensive review of potential risk factors for infections and therapeutic approaches for the most prevalent infections in patients with solid tumors, and discusses the potential effect of antibiotic therapy on toxicity and efficacy of cancer therapy.

Antibiotic Therapy is Associated with Worse Outcome in Patients with Hepatocellular Carcinoma Treated with Sorafenib

Background

Antibiotic treatment (ABT) affects the outcome of cancer patients treated with immune checkpoint inhibitors (ICIs) and chemotherapy, possibly by altering the gut microbiome. We investigated the impact of ABT on overall survival (OS) and progression-free survival (PFS) in patients with advanced HCC treated with sorafenib.

Methods

HCC patients treated with sorafenib between 05/2006 and 03/2020 at the Medical University of Vienna were retrospectively analyzed. ABT was defined as antibiotic use within 30 days prior to or after sorafenib initiation.

Results

Of 206 patients, the majority was male (n=171, 83%) with a mean age of 66±9.6 years. Half of patients (n=94, 46%) had impaired liver function (Child-Pugh stage B). Median time of follow-up was 10.8 (95% CI: 9.2-12.3) months. ABT was administered in 23 (11%) patients due to different types of proven or clinically suspected bacterial infections (n=17, 74%) and hepatic encephalopathy (n=6, 26%). The median duration of ABT was 14 (IQR: 12-30) days. Penicillin (n=13, 57%), followed by rifaximin (n=6, 26%), fluoroquinolones (n=3, 13%), and cephalosporins (n=1, 4%), was administered in the ABT group. The ABT group had a significantly shorter median OS (4.7 (95% CI: 3.2-6.1) months vs 11.4 (95% CI: 9.9-12.9) months, p=0.012), which was confirmed in multivariable analysis (HR: 1.91 (95% CI: 1.1-3.2), p=0.014). Similarly, PFS trended to be shorter in the ABT group (3.5 (95% CI: 1.6-5.4) months vs 4.8 (95% CI: 3.9-5.7) months, p=0.099). None of the 10 patients with complete or partial response was found in the ABT group.

Conclusion

ABT was independently associated with worse outcomes in sorafenib-treated HCC patients. Prospective studies are needed to elucidate the underlying mechanism.

Mining the Gut Microbiota for Microbial-Based Therapeutic Strategies in Cancer Immunotherapy

The past two decades witnessed a revolution in our understanding of host–microbiota interactions that led to the concept of the super-organism consisting of a eukaryotic part and a prokaryotic part. Owing to the critical role of gut microbiota in modulating the host immune system, it is not beyond all expectations that more and more evidence indicated that the shift of gut microbiota influenced responses to numerous forms of cancer immunotherapy. Therapy targeting gut microbiota is becoming a promising strategy to improve cancer immunotherapy. In this review, we discuss the role of the gut microbiota in response to cancer immunotherapy, the mechanisms that the gut microbiota influences cancer immunotherapy, and therapeutic strategies targeting gut microbiota to improve cancer immunotherapy.

[The role of the microbiome in urological diseases]

The use of modern molecular technologies in the last decade has given us new insights into the complex interactions of the human microbiome in health and in the pathogenesis of diseases. Among other things, the sterility concept of the urinary tract has been discarded and the goal is now to identify the different microbial signatures associated with various diseases. Dysbalances of the microbiome are increasingly suspected of causing negative effects on various malignant and benign diseases. Recently, such associations have also been shown for prostate carcinoma, renal cell carcinoma and urinary bladder carcinoma. This may lead to the discovery of new potential biomarkers for the diagnosis and as a therapeutic target of the diseases mentioned. For the diagnosis of some benign diseases such as interstitial cystitis, urge incontinence and chronic prostatitis or chronic pelvic pain syndrome, microbial involvement was previously considered an exclusion criterion. However, current studies show that the individual patient's microbiome can have an influence on the development and severity of the respective disease.

Antibiotic use influences outcomes in advanced pancreatic adenocarcinoma patients

Recent studies defined a potentially important role of the microbiome in modulating pancreatic ductal adenocarcinoma (PDAC) and responses to therapies. We hypothesized that antibiotic usage may predict outcomes in patients with PDAC.

We retrospectively analyzed clinical data of patients with resectable or metastatic PDAC seen at MD Anderson Cancer from 2003 to 2017. Demographic, chemotherapy regimen and antibiotic use, duration, type, and reason for indication were recorded.

A total of 580 patients with PDAC were studied, 342 resected and 238 metastatic patients, selected retrospectively from our database. Antibiotic use, for longer than 48 hrs, was detected in 209 resected patients (61%) and 195 metastatic ones (62%). On resectable patients, we did not find differences in overall survival (OS) or progression‐free survival (PFS), based on antibiotic intake. However, in the metastatic cohort, antibiotic consumption was associated with a significantly longer OS (13.3 months vs. 9.0 months, HR 0.48, 95% CI 0.34–0.7, p = 0.0001) and PFS (4.4 months vs. 2 months, HR 0.48, 95% CI 0.34–0.68, p = <0.0001). In multivariate analysis, the impact of ATB remained significant for PFS (HR 0.59, p = 0.005) and borderline statistically significant for OS (HR 0.69, p = 0.06). When we analyzed by chemotherapy regimen, we found that patients who received gemcitabine‐based chemotherapy as first‐line therapy (n = 118) had significantly prolonged OS (HR 0.4, p 0.0013) and PFS (HR 0.55, p 0.02) if they received antibiotics, while those receiving 5FU‐based chemotherapy (n = 98) had only prolonged PFS (HR 0.54, p = 0.03).

Antibiotics‐associated modulation of the microbiome is associated with better outcomes in patients with metastatic PDAC.

We have analyzed the effect of antibiotics’ intake on two cohorts of patients with pancreatic adenocarcinoma, resectable, and metastatic. We have found that on the metastatic cohort, antibiotics use was significantly associated with better outcomes, particularly, on patients that received gemcitabine based‐chemotherapy as the first line.

Gut microbiota-mediated immunomodulation in tumor

Tumor immunity consists of various types of cells, which serve an important role in antitumor therapy. The gastrointestinal tract is colonized by trillions of microorganisms, which form the gut microbiota. In addition to pathogen defense and maintaining the intestinal ecosystem, gut microbiota also plays a pivotal role in various physiological processes. Recently, the association between these symbionts and cancer, ranging from oncogenesis and cancer progression to resistance or sensitivity to antitumor therapies, has attracted much attention. Metagenome analysis revealed a significant difference between the gut microbial composition of cancer patients and healthy individuals. Moreover, modulation of microbiome could improve therapeutic response to immune checkpoint inhibitors (ICIs). These findings suggest that microbiome is involved in cancer pathogenesis and progression through regulation of tumor immunosurveillance, although the exact mechanisms remain largely unknown. This review focuses on the interaction between the microbiome and tumor immunity, with in-depth discussion regarding the therapeutic potential of modulating gut microbiota in ICIs. Further investigations are warranted before gut microbiota can be introduced into clinical practice.

The association between antibiotic use and survival in renal cell carcinoma patients treated with immunotherapy: a multi-center study

BACKGROUND

Immunotherapy improves overall survival (OS) in the second and later lines of renal cell carcinoma (RCC) treatment. Recent studies have suggested that antibiotic (ATB) use either shortly before or after the start of immunotherapy could lead to decreased OS. Herein, we evaluate the impact of ATB use on OS in RCC patients treated with nivolumab in a multi-center cohort from Turkey.

METHODS

The data of 93 metastatic RCC patients treated with nivolumab in the second line or later were retrospectively collected from 6 oncology centers. Previous treatments, sites of metastases, International Metastatic RCC Database Consortium risk classification, and ATB use in the three months before (-3) or three months after (+3) the start of immunotherapy were recorded together with survival data. The association of clinical factors with OS and progression-free survival (PFS) was analyzed with univariate and multivariable analyses.

RESULTS

The median age was 61 (interquartile range 54-67), and 76.3% of the patients were male. The median OS of the cohort was 23.75 ± 4.41, and the PFS was 8.44 ± 1.61 months. Thirty-one (33.3%) patients used ATBs in the 3 months before (-3) or 3 months after (+3) nivolumab initiation. In the multivariable analyses, ATB exposure (HR: 2.306, 95% confidence interval [CI]: 1.155-4.601, P = 0.018) and the presence of brain metastases at the baseline (HR: 2.608, 95% CI: 1.200-5.666, P = 0.015) had a statistically significant association with OS, while ATB exposure was the only statistically significant parameter associated with PFS (HR: 2.238, 95% CI: 1.284-3.900, P = 0.004).

CONCLUSION

In our study, patients with ATB exposure in the 3 months before or 3 months after the start of immunotherapy had shorter OS. Our findings further support meticulous risk-benefit assessments of prescribing ATBs for patients who are either receiving or are expected to receive immunotherapy.

Is There a Detrimental Effect of Antibiotic Therapy in Patients with Muscle-invasive Bladder Cancer Treated with Neoadjuvant Pembrolizumab?

In locally advanced and metastatic malignancies, antibiotic (ATB) therapy has a negative effect on immunotherapy efficacy. Therefore, we aimed to evaluate whether ATB therapy and use of specific ATB classes with concomitant neoadjuvant pembrolizumab affected pathologic complete response (ypT0N0) and relapse-free survival (RFS) for patients with clinical T2-4N0M0 bladder cancer enrolled in the PURE-01 study. Of the 149 patients evaluated, 48 (32%) received any concomitant ATB therapy. The ATB class most commonly administered was fluoroquinolones (16 patients; 33%). In the ATB cohort, seven patients (15%) achieved ypT0N0 status, compared to 50 (50%; p < 0.001) in the untreated group. Moreover, ATB use was negatively associated with ypT0N0 status (odds ratio 0.18, 95% confidence interval [CI] 0.05-0.48; p = 0.001). The 24-mo RFS rate was 63% (95% CI 48-83%) in the ATB group versus 90% (95% CI 83-97) in the untreated group. We found that ATB use was associated with a higher recurrence rate (hazard ratio [HR] 2.64, 95% CI 1.08-6.50; p = 0.03). Exploratory analyses showed that fluoroquinolone use was associated with a higher recurrence rate (HR 3.28, 95% CI 1.12-9.60; p = 0.03). Our study revealed an association between ATB use and neoadjuvant immunotherapy efficacy in an intention-to-cure population, highlighting the need for future studies to better investigate this relationship. PATIENT SUMMARY: The efficacy of immunotherapy for cancer is influenced by several patient and tumor factors, including the use of antibiotics. We found that antibiotics taken at the same time as immunotherapy drugs were associated with lower rates of complete response and of recurrence-free survival among patients with muscle-invasive bladder cancer. These findings need to be confirmed in future studies.

Use of antibiotics is associated with worse clinical outcomes in patients with cancer treated with immune checkpoint inhibitors: A systematic review and meta-analysis

OBJECTIVES

Observational and experimental studies suggest that the use of antibiotics close to administration of immune checkpoint inhibitors (ICI) can have a negative effect on tumour response and patient survival, due to microbiome dysbiosis and the resultant suppression of host immune response against neoplastic cells.

METHODS

A systematic search of PUBMED and EMBASE was undertaken for studies published between 1 January 2017 and 1 June 2020, evaluating the association between the use of antibiotics and clinical outcomes in patients with cancer treated with ICIs. A meta-analysis of the association between the use of antibiotics and clinical outcomes was also performed.

RESULTS

Forty-eight studies met the inclusion criteria (12,794 patients). Use of antibiotics was associated with shorter overall survival [hazard ratio (HR) 1.88, 95% confidence interval (CI) 1.59-2.22; adjusted HR 1.87, 95% CI 1.55-2.25] and progression-free survival (HR 1.52, 95% CI 1.36-1.70; adjusted HR 1.93, 95% CI 1.59-2.36), decreased response rate [odds ratio (OR) 0.54, 95% CI 0.34-0.86] and more disease progression (OR 2.00, 95% CI 1.27-3.14). The negative association between the use of antibiotics and progression-free survival was stronger in patients with renal cell carcinoma or melanoma compared with lung cancer. Only antibiotic administration >1 month prior to ICI initiation was associated with increased disease progression. Heterogeneity was substantial for all outcomes.

CONCLUSIONS

Recent use of antibiotics in patients with cancer treated with ICIs was associated with worse clinical outcomes. Such patients may benefit from dedicated antimicrobial stewardship programmes.

Relating Gut Microbiome and Its Modulating Factors to Immunotherapy in Solid Tumors: A Systematic Review

Background: Gut microbiome is proved to affect the activity of immunotherapy in certain tumors. However, little is known if there is universal impact on both the treatment response and adverse effects (AEs) of immune checkpoint inhibitors (ICIs) across multiple solid tumors, and whether such impact can be modulated by common gut microbiome modifiers, such as antibiotics and diet.

Methods: A systematic search in PubMed followed by stringent manual review were performed to identify clinical cohort studies that evaluated the relevance of gut microbiome to ICIs (response and/or AEs, 12 studies), or association of antibiotics with ICIs (17 studies), or impact of diet on gut microbiome (16 studies). Only original studies published in English before April 1st, 2020 were used. Qualified studies identified in the reference were also included.

Results: At the phylum level, patients who had enriched abundance in Firmicutes and Verrucomicrobia almost universally had better response from ICIs, whereas those who were enriched in Proteobacteria universally presented with unfavorable outcome. Mixed correlations were observed for Bacteroidetes in relating to treatment response. Regarding the AEs, Firmicutes correlated to higher incidence whereas Bacteroidetes were clearly associated with less occurrence. Interestingly, across various solid tumors, majority of the studies suggested a negative association of antibiotic use with clinical response from ICIs, especially within 1-2 month prior to the initiation of ICIs. Finally, we observed a significant correlation of plant-based diet in relating to the enrichment of “ICI-favoring” gut microbiome (P = 0.0476).

Conclusions: Gut microbiome may serve as a novel modifiable biomarker for both the treatment response and AEs of ICIs across various solid tumors. Further study is needed to understand the underlying mechanism, minimize the negative impact of antibiotics on ICIs, and gain insight regarding the role of diet so that this important lifestyle factor can be harnessed to improve the therapeutic outcomes of cancer immunotherapy partly through its impact on gut microbiome.

Gut Microbiota in Cancer Immune Response and Immunotherapy

The gastrointestinal tract (GIT) is the largest immune organ and maintains systemic immune homeostasis in the presence of bacterial challenge. Immune elimination and immune escape are hallmarks of cancer, both of which can be partly bacteria dependent in shaping immunity by mediating host immunomodulation. In addition, host immunity regulates the microbiome by altering bacteria-associated signaling to influence tumor surveillance. Cancer immunotherapy, including immune checkpoint blockade (ICB), appears to have heterogeneous therapeutic effects in different individuals, partially attributed to the microbiota. Thus, the microbiome signature can predict clinical outcomes, prognosis, and immunotherapy responses. In this review, we summarize the intricate crosstalk among the gut microbiome, cancer immune response, and immunotherapy. Interactive modulation of the host microbiota provides new therapeutic strategies to promote anticancer therapy efficacy and/or reduce toxicity.

What Is Known about Theragnostic Strategies in Colorectal Cancer

Despite the paradigmatic shift occurred in recent years for defined molecular subtypes in the metastatic setting treatment, colorectal cancer (CRC) still remains an incurable disease in most of the cases. Therefore, there is an urgent need for new tools and biomarkers for both early tumor diagnosis and to improve personalized treatment. Thus, liquid biopsy has emerged as a minimally invasive tool that is capable of detecting genomic alterations from primary or metastatic tumors, allowing the prognostic stratification of patients, the detection of the minimal residual disease after surgical or systemic treatments, the monitoring of therapeutic response, and the development of resistance, establishing an opportunity for early intervention before imaging detection or worsening of clinical symptoms. On the other hand, preclinical and clinical evidence demonstrated the role of gut microbiota dysbiosis in promoting inflammatory responses and cancer initiation. Altered gut microbiota is associated with resistance to chemo drugs and immune checkpoint inhibitors, whereas the use of microbe-targeted therapies including antibiotics, pre-probiotics, and fecal microbiota transplantation can restore response to anticancer drugs, promote immune response, and therefore support current treatment strategies in CRC. In this review, we aim to summarize preclinical and clinical evidence for the utilization of liquid biopsy and gut microbiota in CRC.

Effects of Antibiotic Use on Outcomes in Cancer Patients Treated Using Immune Checkpoint Inhibitors: A Systematic Review and Meta-Analysis

Antibiotic (ATB) use seems to negatively affect the outcomes of immune checkpoint inhibitors (ICIs). The aim of this review is to clarify whether ATB use influences the efficacy of ICI treatment in cancer patients. Databases of MEDLINE, Embase, and Cochrane Library were searched for reports published in English between January 2007 and December 2019. We included studies that compared the outcomes of ATB use and no-ATB use in cancer patients using ICIs. Two reviewers independently selected eligible studies and extracted the data. Meta-analysis was performed with pooling of unadjusted hazard ratios (HRs) for overall survival (OS) and progression-free survival (PFS), and with pooling of odds ratios (ORs) for objective response rate (ORR). Thirty-eight studies involving 8409 patients were finally included for qualitative or quantitative analyses. Cancer types included renal cell carcinoma, non-small cell lung cancer, urothelial carcinoma, melanoma, gastrointestinal cancer, and others. Meta-analyses revealed that ATB use was associated with poor OS [HR: 1.80, 95% confidence interval (CI): 1.44-2.26, P<0.001], PFS (HR: 1.55, 95% CI: 1.26-1.91, P<0.001) and ORR (OR: 0.63, 95% CI: 0.42-0.95, P=0.03). Subgroup analysis found that these relationships were not influenced by cancer type or ICI regimens, but were dependent on the timing of ATB use. Narrative results of multivariable analyses further confirmed the negative effects of ATB use on OS and PFS. In cancer patients using ICIs, pre-ATB use close to the start of ICI treatment (within 60 d) was detrimental to outcomes in terms of OS, PFS, and ORR.

Impact of antibiotic treatment on immunotherapy response in women with recurrent gynecologic cancer

OBJECTIVE(S)

To identify whether antibiotics (ABX) impact immunotherapy (ICI) response rate (RR), progression-free survival (PFS), and overall survival (OS) in women with recurrent endometrial (EC), cervical (CC) and ovarian cancer (OC).

METHODS

This retrospective cohort study included women with recurrent EC, CC, and OC treated with ICIs from 1/1/17-9/1/2020. ABX were defined as 30 days before (pABX) or concurrently (cABX) with ICI. The impact of ABX upon PFS and OS was assessed by univariate analysis and multivariable Cox regression.

RESULTS

Of 101 women, 52.5% (n = 53) had recurrent EC, 21.4% (n = 22) CC and 25.7% (n = 26) OC. 56.9% (n = 58) received ABX, with 22.8% (n = 23) pABX and 46.5% (n = 47) cABX. While no difference was observed in ICI RR for any ABX vs. none (p = 0.89) and cABX vs. none (p = 0.33), pABX (n = 23) were associated with decreased RR vs. none (n = 78) (Partial Response - 8.7% vs. 30.8%; Complete Response - 4.3% vs. 9.0%; p = 0.002). On univariate analysis, pABX were associated with worsened PFS (2.9 vs. 8.9 months; HR 2.53, 95% CI 1.48-4.31, p < 0.001) and OS (9.3 vs. 19.9 months; HR 2.29, 95% CI 1.22-4.32, p = 0.01). No PFS or OS difference was noted for cABX (PFS - 9.3 vs. 6.0 months; HR 0.70, 95% CI 0.43-1.12; p = 0.14; OS - 13.4 vs. 16.3 months; HR 0.89, 95% CI 0.51-1.54; p = 0.68). On multivariable analysis, pABX were associated with significantly decreased PFS (HR 3.10, 95% CI 1.75-5.49, p < 0.001) and OS (HR 3.03, 95% CI 1.50-6.10, p = 0.002).

CONCLUSIONS

In women with recurrent EC, OC, and CC receiving ICI, pABX, but not cABX, are associated with decreased RR, PFS, and OS. Further investigation is warranted to understand predictors of ICI response in women with gynecologic cancer.

Uncovering the microbiota in renal cell carcinoma tissue using 16S rRNA gene sequencing

INTRODUCTION

Increasing evidence indicates an important role of microbiota in cancer development and progression, while little is known about the correlation between microbiota and renal cell carcinoma (RCC). Thus, we performed this study to profile the intratumoral microbiota possibly associated with RCC.

MATERIALS AND METHODS

Paired RCC and adjacent normal tissue samples were collected from 24 patients with RCC. V3-V4 variable region of microbial 16S rRNA gene was sequenced using Illumina MiSeq. Sequencing reads were processed using QIIME. Differentially abundant bacterial taxa between groups were identified by LEfSe, and their potential functions were inferred by PICRUSt.

RESULTS

Decreased species diversity was presented in RCC tissues (Simpson index, P = 0.0340), and the composition of the bacterial community in RCC tissues was significantly distinct from that in normal tissues (unweighted UniFrac distance, P = 0.026; weighted UniFrac distance, P = 0.017). Compared with normal tissues, 25 taxa increased and 47 reduced taxa were identified in RCC tissues. Among these taxa, the class Chloroplast (AUC = 0.91, P < 0.0001) and the order Streptophyta (AUC = 0.89, P < 0.0001) showed high indication accuracy to discriminate RCC tissues from normal tissues. Furthermore, nine altered pathways were identified in RCC tissues to reveal the potential microbial function.

CONCLUSIONS

Our results have uncovered the presence of distinct microbiota in RCC and adjacent normal tissues and provided a better understanding of the possible role of the intratumoral microbiota in RCC. Further studies are required to confirm our results and determine the real correlation between microbiota and RCC.

The human microbiome and genitourinary malignancies

The human microbiome contains a vast network of understudied organisms that have an intimate role in our health and wellness. These microbiomes differ greatly between individuals, creating what may be thought of as a unique and dynamic microbial signature. Microbes have been shown to have various roles in metabolism, local and systemic inflammation, as well as immunity. Recent findings have confirmed the importance of both the gut and urinary microbiomes in genitourinary malignancies. Numerous studies have identified differences in microbial signatures between healthy patients and those with urologic malignancies. The microbiomes have been shown to contain microbes that may contribute to the etiology of disease state as well as yield information in regard to a person’s health and their responsiveness to certain drugs such as immune checkpoint inhibitors (ICIs) and tyrosine kinase inhibitors (TKIs). Less well understood are the effects of antibiotics on oncologic outcomes in such treatment courses. This review will explore our current understanding and advancements in the field of microbiome research and discuss its intimate association with genitourinary diseases including bladder cancer, prostate cancer, and kidney cancer. With a better understanding of the association between the microbiome and genitourinary malignancy, further investigation may produce reliable predictors of disease, prognostic indicators as well as therapeutic targets.

Bugs as drugs: The role of microbiome in cancer focusing on immunotherapeutics

The human microbiome comprising microorganisms, their collective genomes and metabolic products has gained tremendous research interest in oncology, as multiple cohorts and case studies have demonstrated discernible interpatient differences in this ecosystem based on clinical variables including disease type, stage, diet, antibiotic usage, cancer treatments, therapeutic responses and toxicities. The modulation of the gut microbiome is the subject of many ongoing preclinical and clinical investigations, through the manipulation of diet, as well as the use of prebiotics, probiotics, specific antibiotics, fecal microbial transplantation, microbial consortia and stool substitutes. Standardization and quality control are needed to maximize the information being generated in this growing field, ranging from technical assays to measure microbiome composition, to methodological aspects in the analysis and reporting of results. Proof-of-mechanism and proof-of-concept clinical trials with appropriate controls are needed to confirm or refute the feasibility, safety and ultimately the clinical utility of human microbiome modulation in cancer patients.

[The role of the microbiome in urology]

With the advent of novel high throughput-sequencing technologies we gained greater insights into the complex and diverse interactions of the microbiome for health and disease in the human body. The concept of urinary sterility has long been dismissed and now we strive for deciphering various microbial signatures associated with a disease. A dysbalance of the microbiome appears to have a substantial impact on the pathogenesis of both malignant and benign conditions. Novel preventive and therapeutic approaches and biomarker systems have been proposed for prostate cancer, renal cell carcinoma and bladder cancer based on microbiome analyses. The exclusion of a microbial origin was always part of the diagnosis of benign disorders such as interstitial cystitis, urinary urge incontinence or chronic prostatitis/chronic pelvic pain syndrome. Now we are certain that an imbalanced microbial profile plays an essential role for the pathogenesis and disease management of these challenging conditions.

Predicting Response to Immunotherapy in Metastatic Renal Cell Carcinoma

Simple Summary

Immunotherapy-based treatment options have become standard of care in metastatic renal cell carcinoma. Despite significant improvement in overall survival with these therapies, the tumors of many patients will eventually progress. This review highlights the ongoing efforts to develop biomarkers to help predict which patients are most likely to benefit from treatment with immunotherapy.

Abstract

Immunotherapy-based combinations, driven by PD-1, PD-L1, and CTLA-4 inhibitors, has altered the treatment landscape for metastatic renal cell carcinoma (RCC). Despite significant improvements in clinical outcomes, many patients do not experience deep or lasting benefits. Recent efforts to determine which patients are most likely to benefit from immunotherapy and immunotherapy-based combinations have shown promise but have not yet affected clinical practice. PD-L1 expression via immunohistochemistry (IHC) has shown promise in a few clinical trials, although variations in the IHC assays as well as the use of different values for positivity presents unique challenges for this potential biomarker. Several other candidate biomarkers were investigated including tumor mutational burden, gene expression signatures, single gene mutations, human endogenous retroviruses, the gastrointestinal microbiome, and peripheral blood laboratory markers. While individually these biomarkers have yet to explain the heterogeneity of treatment response to immunotherapy, using aggregate information from these biomarkers may inform clinically useful predictive biomarkers.

A Significant Question in Cancer Risk and Therapy: Are Antibiotics Positive or Negative Effectors? Current Answers and Possible Alternatives

Cancer is predominantly considered as an environmental disease caused by genetic or epigenetic alterations induced by exposure to extrinsic (e.g., carcinogens, pollutants, radiation) or intrinsic (e.g., metabolic, immune or genetic deficiencies). Over-exposure to antibiotics, which is favored by unregulated access as well as inappropriate prescriptions by physicians, is known to have led to serious health problems such as the rise of antibiotic resistance, in particular in poorly developed countries. In this review, the attention is focused on evaluating the effects of antibiotic exposure on cancer risk and on the outcome of cancer therapeutic protocols, either directly acting as extrinsic promoters, or indirectly, through interactions with the human gut microbiota. The preponderant evidence derived from information reported over the last 10 years confirms that antibiotic exposure tends to increase cancer risk and, unfortunately, that it reduces the efficacy of various forms of cancer therapy (e.g., chemo-, radio-, and immunotherapy alone or in combination). Alternatives to the current patterns of antibiotic use, such as introducing new antibiotics, bacteriophages or enzybiotics, and implementing dysbiosis-reducing microbiota modulatory strategies in oncology, are discussed. The information is in the end considered from the perspective of the most recent findings on the tumor-specific and intracellular location of the tumor microbiota, and of the most recent theories proposed to explain cancer etiology on the notion of regression of the eukaryotic cells and systems to stages characterized for a lack of coordination among their components of prokaryotic origin, which is promoted by injuries caused by environmental insults.