Efficacy and Safety of Probiotics Combined With Standard Chemotherapy Plus Targeted Therapy in Patients With Metastatic Colorectal Cancer: A Prospective, Open-Label，Randomized, Multi-center Clinical Trial

Bifico (also known as "bifidobacterium trifidum live powder") is a probiotic preparation that has been marketed and widely used in China. The number of live bacteria of lactobacillus acidophilus and bifidobacterium per gram should not be less than 1.0×107CFU. At present, it is mainly used for diarrhea and abdominal distension caused by intestinal flora imbalance. It can also be used for treating mild to moderate acute diarrhea and chronic diarrhea. Lactobacillus acidophilus and bifidobacteria have been fully proved in basic studies to improve gut microbiological environment and inhibit colorectal cancer. A recent paper published by Nature Biomedical Engineering reported that chemotherapy can effectively enhance the efficacy of colon cancer by regulating intestinal flora. Based on the above evidence, we propose that the current standard chemotherapy plus targeted therapy regimen combined with Bifico can exert a more powerful synergistic anticancer effect. To sum up, this study put forward innovative joint regulating intestinal flora environment with standard chemotherapy and target therapy of new concept and mode, to assess Bifico combined with standard chemotherapy plus targeted therapy compared to standard chemotherapy plus targeted therapy for efficacy and safety of metastatic colorectal cancer, combined with the intestinal flora, probiotics patient blood DNA analysis, etc. New technology, explore flora index correlation with the prognosis of patients' immune system function, and its potential as a predictive marker. It is worth noting that this study will closely combine the current most advanced intestinal flora 16S microbial polymorphism detection and single-cell sequencing technology, so as to truly achieve accurate and individualized treatment, evaluation and prognosis prediction.