Probiotics, postbiotics, and synbiotics in the prevention of oncological diseases.

BACKGROUND: In the context of oncological diseases of (not only) the gastrointestinal tract and the oral cavity, the role of microorganisms is being increasingly discussed and investigated. A growing body of evidence supports the significance of specific microbial strains and their products both in the etiopathogenesis of certain cancers and in their prevention and therapy. AIM: This review summarizes recent findings on the targeted modulation of the human microbiota using probiotics (including Bifidobacteria, Lactobacilli, etc.), their products (postbiotics, e. g. butyrate), and formulations combining probiotics with prebiotics (synbiotics), in the context of cancer prevention and progression, adverse effects of anticancer therapy, and associated complications related to the disease and surgical treatment. The results of clinical studies demonstrate the benefits of these preparations, particularly in preventing and alleviating gastrointestinal symptoms and postoperative infectious complications, as well as inflammatory mucosal damage (including oral mucositis) in oncology patients, with multi-strain probiotic formulations demonstrating greater efficacy. Research is even underway in animal models to explore the use of probiotics in immunotherapy. Despite the promising results obtained from modulating the human microbiota to improve the quality of life of cancer patients, as well as for cancer prevention and potentially even therapy, broader clinical implementation is limited by interindividual variability of the microbiome, safety concerns in immunocompromised patients, and the insufficiently documented quality of some available products. Nevertheless, given the undeniable mechanistic and translational potential of probiotic, postbiotic, and synbiotic supplementation, continued clinical research in this field is highly warranted.