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Background: Emerging evidence suggests that gut microbiota influences the clinical response to immunotherapy. This review of clinical studies examines the relationship between gut microbiota and immunotherapy outcomes. Method: A literature search was conducted in electronic databases Medline, PubMed and ScienceDirect, with searches for "cancer" and "immunotherapy/immune checkpoint inhibitor" and "microbiome/microbiota" and/or "fecal microbiome transplant FMT". The relevant literature was selected for this article. Results: Ten studies examined patients diagnosed with advanced metastatic melanoma (n = 6), hepatocellular carcinoma (HCC) (n = 2), non-small cell lung carcinoma (NSCLC) (n = 1) and one study examined combination both NSCLC and renal cell carcinoma (RCC) (n = 1). These studies consistently reported that the gut microbiome profile prior to administering immune checkpoint inhibitors (ICIs) was related to clinical response as measured by progression-free survival (PFS) and overall survival (OS). Two studies reported that a low abundance of Bacteroidetes was associated with colitis. Two studies showed that patients with anti-PD-1 refractory metastatic melanoma experienced improved response rates and no added toxicity when receiving fecal microbiota transplant (FMT) from patients with anti-PD-1 responsive disease. Conclusions: Overall, significant differences in the diversity and composition of the gut microbiome were identified in ICIs responders and non-responders. Our findings provide new insights into the value of assessing the gut microbiome in immunotherapy. Further robust randomized controlled trials (RCTs) examining the modulatory effects of the gut microbiome and FMT on ICIs in patients not responding to immunotherapy are warranted.
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Increasing evidence suggests that the gut microbiome is associated with both cancer chemotherapy (CTX) outcomes and adverse events (AEs). This review examines the relationship between the gut microbiome and CTX as well as the impact of CTX on the gut microbiome. A literature search was conducted in electronic databases Medline, PubMed and ScienceDirect, with searches for "cancer" and "chemotherapy" and "microbiome/microbiota". The relevant literature was selected for use in this article. Seventeen studies were selected on participants with colorectal cancer (CRC; n=5), Acute Myeloid Leukemia (AML; n=3), Non-Hodgkin's lymphoma (n=2), breast cancer (BCa; n=1), lung cancer (n=1), ovarian cancer (n=1), liver cancer (n=1), and various other types of cancers (n=3). Seven studies assessed the relationship between the gut microbiome and CTX with faecal samples collected prior to (n=3) and following CTX (n=4) showing that the gut microbiome is associated with both CTX efficacy and toxicity. Ten other prospective studies assessed the impact of CTX during treatment and found that CTX modulates the gut microbiome of people with cancer and that dysbiosis induced by the CTX is related to AEs. CTX adversely impacts the gut microbiome, inducing dysbiosis and is associated with CTX outcomes and AEs. Current evidence provides insights into the gut microbiome for clinicians, cancer survivors and the general public. More research is required to better understand and modify the impact of CTX on the gut microbiome.
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BACKGROUND: Gastrointestinal (GI) toxicities are common adverse effects of pelvic radiotherapy (RT). Several recent studies revealed that toxicity of RT is associated with dysbiosis of the gut microbiome. METHOD: A literature search was conducted in electronic databases Medline, PubMed, and ScienceDirect, with search terms "microbiome and/or microbiota" and "radiotherapy (RT) and/or chemoradiation therapy (CRT)" and "cancer", and the relevant literature were selected for use in this article. RESULTS: Eight prospective cohort studies were selected for review with a total of 311 participants with a range of 15-134 participants within these studies. The selected studies were conducted in patients with gynaecological (n = 3), rectal (n = 2), or prostate cancers (n = 1), or patients with various types of malignancies (n = 2). Three studies reported that cancer patients had significantly lower alpha diversity compared with healthy controls. Seven studies found that lower alpha diversity and modulated gut microbiome were associated with GI toxicities during and after pelvic RT (n = 5) and CRT (n = 2), whereas one study found that beta diversity was related to a complete response following CRT. Two further studies reported that fatigue was associated with dysbiosis of the gut microbiome and low alpha diversity during and after RT, and with dysbiosis of the gut microbiome and diarrhoea, respectively. CONCLUSION: Gut microbiome profiles are associated with GI toxicities and have the potential to predict RT/CRT-induced toxicities and quality of life (QoL) in patients undergoing those treatments. Further robust randomized controlled trials (RCTs) are required to elucidate the effect of gut microbiome profiles on RT-related adverse effects and responses to RT.
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Background: Effective preventative health interventions are essential to maintain well-being among healthcare professionals and the public, especially during times of health crises. Several studies have suggested that Tai Chi and Qigong (TQ) have positive impacts on the immune system and its response to inflammation. The aim of this review is to evaluate the current evidence of the effects of TQ on these parameters. Methods: Electronic searches were conducted on databases (Medline, PubMed, Embase and ScienceDirect). Searches were performed using the following keywords: "Tai Chi or Qigong" and "immune system, immune function, immunity, Immun*, inflammation and cytokines". Studies published as full-text randomized controlled trials (RCTs) in English were included. Estimates of change in the levels of immune cells and inflammatory biomarkers were pooled using a random-effects meta-analysis where randomised comparisons were available for TQ versus active controls and TQ versus non-active controls. Results: Nineteen RCTs were selected for review with a total of 1686 participants and a range of 32 to 252 participants within the studies. Overall, a random-effects meta-analysis found that, compared with control conditions, TQ has a significant small effect of increasing the levels of immune cells (SMD, 0.28; 95% CI, 0.13 to 0.43, p = 0.00), I2 = 45%, but not a significant effect on reducing the levels of inflammation (SMD, -0.15; 95% CI, -0.39 to 0.09, p = 0.21), I2 = 85%, as measured by the systemic inflammation biomarker C-reactive protein (CRP) and cell mediated biomarker cytokines. This difference in results is due to the bidirectional regulation of cytokines. An overall risk of bias assessment found three RCTs with a low risk of bias, six RCTs with some concerns of bias, and ten RCTs with a high risk of bias. Conclusions: Current evidence indicates that practising TQ has a physiologic impact on immune system functioning and inflammatory responses. Rigorous studies are needed to guide clinical guidelines and harness the power of TQ to promote health and wellbeing.
