Impact of the use of antibiotics on the clinical response to immune checkpoint inhibitors in patients with non-small cell lung cancer

Antibiotic use during radical surgery in stage I-III colorectal cancer: correlation with outcomes?

AIMS

Accumulating evidence indicates that the use of antibiotics (ATBs) in cancer patients is potentially correlated with patient prognosis. Interestingly, the use of these agents is not uncommon in colorectal cancer (CRC) patients during surgery; however, their prognostic value in the clinic has never been addressed.

MATERIALS AND METHODS

Data on ATB use during surgery, including the cumulative defined daily dose (cDDD) and the number of categories, were collected. Differences in the clinical data between the low and high cDDD subgroups and between subgroups with ≤ 4 and >4 categories. Additionally, the disease-free survival (DFS) and overall survival (OS) among these subgroups and the specific categories were compared. Finally, a Cox proportional hazard model was used to validate the risk factors for the outcome.

RESULTS

The number of categories, rather than the cDDD, was a significant predictor of both DFS (P = 0.043) and OS (P = 0.039). Patients with obstruction are more likely to have a high cDDD, whereas older patients are more likely to have multiple categories. There were no significant differences in the DFS (log rank = 1.36, P = 0.244) or OS (log rank = 0.40, P = 0.528) between patients in the low- and high-cDDD subgroups, whereas patients with ≤ 4 categories had superior DFS (log rank = 9.92, P = 0.002) and OS (log rank = 8.30, P = 0.004) compared with those with >4 categories. Specifically, the use of quinolones was harmful to survival (DFS: log rank = 3.67, P = 0.055; OS: log rank = 5.10, P = 0.024), whereas the use of macrolides was beneficial to survival (DFS: log rank = 12.26, P < 0.001; OS: log rank = 9.77, P = 0.002). Finally, the number of categories was identified as an independent risk factor for both DFS (HR = 2.05, 95% CI: 1.35-3.11, P = 0.001) and OS (HR = 1.82, 95% CI: 1.14-2.90, P = 0.012).

CONCLUSIONS

The cDDD of ATBs during surgery in stage I-III CRC patients did not correlate with outcome; however, patients in multiple categories or a specific category are likely to have inferior survival. These results suggest that particular caution should be taken when selecting ATBs for these patients in the clinic.

Antibiotic treatment and survival in non-small cell lung cancer patients receiving immunotherapy: a systematic review and meta-analysis

Background

In patients with non-small cell lung cancer (NSCLC), immune checkpoint inhibitors (ICIs) are an effective mode of treatment. Despite their efficacy, responses to ICIs have been shown to differ based on several factors; for example, antibiotic use prior to and/or during immunotherapy has been associated with lower survival in NSCLC patients. The objective of this study is to provide an updated review of the literature and to fill in important knowledge gaps by accounting for potential confounding in the relationship between ICIs and survival.

Methods

We performed a systematic review and meta-analysis on peer-reviewed studies that examined the effects of antibiotic use on overall survival (OS) and progression-free survival (PFS) in NSCLC patients treated with ICIs. We searched MEDLINE for studies published up to June 30th, 2023 that included NSCLC patients treated with anti-programmed cell death protein 1 (PD-1) or programmed death-ligand 1 (PD-L1) agents, who received antibiotics before and/or during immunotherapy, and included a control group who did not receive antibiotics and had available data on the associations between antibiotics and OS and PFS. We calculated aggregated crude OS and PFS for all studies, and only for studies that reported multivariable hazard ratios (HRs). Risk of bias was assessed using a funnel plot. All results were synthesized and displayed using the metaphor statistical package in R, version 4.2.1.

Results

Nineteen studies, conducted between 2017 and 2022, met the inclusion criteria, and included 2,932 patients with advanced and/or metastatic NSCLC. Compared to those who did not receive antibiotics, immunotherapy patients who did had a significantly reduced PFS (HR: 1.22, 95% CI: 1.03-1.44) and OS (HR: 1.56, 95% CI: 1.23-1.99). Adjusted HRs were even more pronounced (OS HRadj: 1.67, 95% CI: 1.23-2.27, PFS HRadj: 1.64, 95% CI: 1.16-2.32).

Conclusions

NSCLC patients treated with antibiotics have significantly lowered survival compared with patients not treated with antibiotics. These results support the hypothesis that antibiotic use in conjunction with ICI among NSCLC patients lowers survival. Limitations of this analysis include the use of studies available only on a single database, limiting the literature search to NSCLC patients, which may impact the generalizability of results to other cancer patient populations, and the inability to account for and adjust the estimates for the same variables (e.g., age, sex) across all studies. Nevertheless, our findings underscore the importance of taking antibiotic use into consideration when using ICIs to treat NSCLC and suggest that confounders should be taken into account when designing future similar studies.

Antibiotics May Interfere with Nivolumab Efficacy in Patients with Head and Neck Squamous Cell Carcinoma

INTRODUCTION

Patients with the head and neck squamous cell carcinoma (SCC) are often treated with immune checkpoint inhibitors (ICIs). Recently, antibiotic intake was reported to lower the efficacy of ICIs in patients with several types of cancers. However, it is unclear if antibiotics affect the efficacy of ICIs in patients with head and neck SCC. We retrospectively assessed the influence of antibiotics on the treatment efficacy of nivolumab, an ICI, in patients with head and neck SCC.

METHODS

We reviewed the medical records of patients with head and neck SCC treated with nivolumab at the Department of Medical Oncology, Tohoku University Hospital, between 2017 and 2021. Patients who received oral or intravenous antibiotics from a month before the day of nivolumab initiation to the day of the first imaging evaluation of ICI efficacy were assigned to the antibiotic-treated group. The remaining patients were assigned to the antibiotic-untreated group. The response rate (RR), progression-free survival (PFS), and overall survival time (OS) of both groups were compared.

RESULTS

Forty-five patients were assigned to the antibiotic-treated group and 19 to the antibiotic-untreated group. The RR, median PFS, and median OS of the antibiotic-treated group were 23.7%, 3.2 months (95% confidential interval [CI]: 2.0-4.1), and 8.4 months (95% CI: 5.3-15.1) and those of the antibiotic-untreated group were 42.1%, 5.8 months (95% CI: 2.3-16.7), and 18.4 months (95% CI: 6.2-23.1), respectively. The PFS of the antibiotic-untreated group was significantly longer than that of the antibiotic-treated group.

CONCLUSION

Our findings indicate that antibiotic treatment significantly shortens the PFS with nivolumab therapy in patients with head and neck SCC.

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.