Immunotherapy with immune checkpoint inhibitors represents a revolutionary approach to the treatment of solid tumors, including malignant melanoma, lung cancer, and gastrointestinal malignancies. Anti-CTLA-4 and anti-PD-1/PDL-1 therapies provide prolonged survival for cancer patients, but their efficacy and safety are highly variable. This review focuses on the crucial role of the gut microbiome in modulating the efficacy and toxicity of immune checkpoint blockade. Studies suggest that the composition of the gut microbiome may influence the response to immunotherapy, with specific bacterial strains able to promote an anti-tumor immune response. On the other hand, dysbiosis may increase the risk of adverse effects, such as immune-mediated colitis. Interventions aimed at modulating the microbiome, including the use of probiotics, prebiotics, fecal microbial transplantation, or dietary modifications, represent promising strategies to increase treatment efficacy and reduce toxicity. The combination of immunotherapy with the microbiome-based strategy opens up new possibilities for personalized treatment. In addition, factors such as physical activity and nutritional supplementation may indirectly influence the gut ecosystem and consequently improve treatment outcomes in refractory patients, leading to enhanced patient responses and prolonged survival.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignant tumors due to the absence of biomarkers for early-stage detection and poor response to therapy. Since mounting evidence supports the role of microbiota composition in tumorigenesis and cancer treatment, the link between microbiome and PDAC has been described. In this review, we summarize the current knowledge regarding the impact of the gut and oral microbiome on the risk of PDAC development. Microenvironment-driven therapy and immune system interactions are also discussed. More importantly, we provide an overview of the clinical trials evaluating the microbiota role in the risk, prognosis, and treatment of patients suffering from PDAC and solid tumors. According to the research findings, immune tolerance might result from the microbiota-derived remodeling of pancreatic tumor microenvironment. Thus, microbiome profiling and targeting represent the potential trend to enhance antitumor immunity and improve the efficacy of PDAC treatment.

Prognostic and predictive significance of inflammatory markers in patients with locally advanced unresectable and metastatic pancreatic cancer treated with first-line chemotherapy FOLFIRINOX or Gemcitabine/Nabpaclitaxel