Probiotic Supplementation During Neoadjuvant Chemoradiotherapy in Colorectal Cancer

This prospective randomized, double-blind, placebo-controlled study evaluated the effects of multistrain probiotic supplementation in patients with stage II-III colorectal cancer undergoing neoadjuvant chemoradiotherapy. Participants received either a multistrain probiotic or placebo twice daily for five weeks during chemoradiotherapy. The study evaluated changes in gut microbiota composition and diversity, as well as fecal short-chain fatty acids, inflammatory cytokines, zonulin, gastrointestinal symptoms, and quality of life. Participants were assessed at baseline, during treatment, at the end of treatment, and seven weeks after completion of treatment.

Inclusion Criteria: * Males and females between 35 and 75 years of age. * Histologically diagnosed stage II-III colorectal cancer. * Tumor stage T2-T4 and/or N1-N2. * Scheduled to receive neoadjuvant chemoradiotherapy consisting of pelvic radiotherapy and oral capecitabine. Exclusion Criteria: * Previous colorectal cancer. * Previous bowel resection. * Type 2 diabetes mellitus. * Chronic inflammatory bowel disease. * Severe infections. * Hereditary colorectal cancer syndromes. * Metastatic disease. * Pregnancy. * Previous pelvic radiotherapy or anti-tumor treatment during the preceding two years. * Antibiotic or immunosuppressive treatment during the preceding two months. * Regular use of NSAIDs. * Regular use of statins. * Regular consumption of probiotics or prebiotics. * Excessive dietary fiber consumption.