Probiotics in the Management of Chemotherapy-Induced Gastrointestinal Complications: Underlying Mechanisms and Potential Applications.

The intestinal microbial population safeguards the gut's health through dynamic interactions with adjacent epithelial and immune cells. Therefore, microbial imbalance in the gastrointestinal (GI) tract may lead to impaired immune system function, disrupted epithelial integrity, and elevated susceptibility to systemic health issues. Chemotherapy, a nonspecific, widely used therapeutic option in cancer treatment, can harm rapidly proliferating intestinal epithelial cells and disrupt intestinal microbial balance, leading to chemotherapy-induced GI adverse events, including mucositis, diarrhea, constipation, bowel inflammation, nausea, vomiting, flatulence, dyspepsia, gastritis, stomatitis, and abdominal pain and distention. These adverse events significantly impair the quality of life of cancer patients. Clinical evidences show promising efficacy for probiotics, especially Lactobacillus spp. and Bifidobacterium spp., in restoring gut microbiota diversity, enhancing mucosal integrity, and modulating inflammatory cytokines (e.g., IL-10, IL-6, and TNF-a). However, study design variabilities, strain-specific effects, and safety concerns in immunocompromised cases remain challenging. This review explores the underlying mechanisms of preventing chemotherapy-induced GI complications using probiotics. Understanding these mechanisms can facilitate probiotic integration into supportive oncology care protocols. This review also highlights the need for standard protocols, personalized therapies, and advanced multi-omics approaches to discover the host-microbe interactions.