Mechanism of Action and Clinical Intervention Potential of Intestinal Dysbiosis in the Occurrence and Development of Gastric Cancer

Abstract

Objective: To explore the mechanism of action of intestinal dysbiosis in the occurrence and development of gastric cancer and analyze its potential for clinical intervention. Methods: Eighty patients with gastric cancer admitted to our hospital from January 2024 to November 2025 were selected as the study group, and another 40 healthy individuals undergoing physical examinations during the same period were selected as the control group. The fecal bacterial and fungal culture method was employed to quantify the primary intestinal flora, including Bifidobacteria, Lactobacilli, Escherichia coli, Enterococci, and Bacteroides, in both groups of study subjects, and the bacilli-to-cocci ratio was calculated. Additionally, serum levels of inflammatory cytokines (IL-6, TNF-α) and immune-related factors (PD-L1, IL-10) were measured. Gastric cancer patients were randomly divided into an intervention group (40 cases) and an observation group (40 cases). The observation group received a conventional chemotherapy regimen, while the intervention group received probiotic intervention in addition to chemotherapy. The incidence of chemotherapy-related adverse reactions and changes in intestinal flora were compared between the two groups. Results: The quantities of Bifidobacteria and Lactobacilli, as well as the bacilli-to-cocci ratio, were significantly lower in the study group compared to the control group, whereas the quantities of Escherichia coli and Enterococci were significantly higher, with all differences being statistically significant (all P < 0.001). Serum levels of IL-6, TNF-α, PD-L1, and IL-10 were significantly higher in the study group than in the control group (P < 0.01). After intervention, the quantities of Bifidobacteria and Lactobacilli, as well as the bacilli-to-cocci ratio, were significantly lower in the observation group than before intervention, while the quantities of Escherichia coli and Enterococci were significantly higher (all P < 0.01). Serum levels of IL-6, TNF-α, PD-L1, and IL-10 in the study group remained significantly higher than those in the control group (P < 0.01). In the intervention group, the quantities of Bifidobacteria and Lactobacilli, as well as the bacilli-to-cocci ratio, were significantly higher after intervention than before, while the quantities of Escherichia coli and Enterococci were significantly lower (all P < 0.001). Furthermore, after intervention, the quantities of Bifidobacteria and Lactobacilli, as well as the bacilli-to-cocci ratio, were significantly higher in the intervention group than in the observation group, while the quantities of Escherichia coli and Enterococci were significantly lower (all P < 0.01). The incidence of adverse reactions was significantly lower in the intervention group than in the observation group (P < 0.001). Conclusion: Dysbiosis of intestinal flora may promote the occurrence and development of gastric cancer through mechanisms such as inducing chronic inflammation and inhibiting anti-tumor immunity; probiotic intervention can effectively regulate the balance of intestinal flora in gastric cancer patients, reduce adverse reactions to chemotherapy, and hold significant potential for clinical intervention.