Probiotics, prebiotics and synbiotics: a role in chemoprevention for colorectal cancer?

Colorectal cancer (CRC) is the third most common form of cancer. Current treatments including chemotherapy, radiotherapy and surgery are all associated with a high risk of complications and are not always successful, highlighting the need to develop new treatment strategies. The ingestion of probiotics, prebiotics or combinations of both (synbiotics) represents a novel new therapeutic option. Probiotics and prebiotics act to alter the intestinal microflora by increasing concentrations of beneficial bacteria such as lactobacillus and bifidobacteria, and reducing the levels of pathogenic micro-organisms. This strategy has the potential to inhibit the development and progression of neoplasia via mechanisms including; decreased intestinal inflammation, enhanced immune function and anti-tumorigenic activity, binding to potential food carcinogens including toxins found in meat products, and a reduction in bacterial enzymes which hydrolyse precarcinogenic compounds, such as beta-glucuronidase. There is substantial experimental evidence to suggest that probiotics and prebiotics may be beneficial in the prevention and treatment of colon cancer, however to date there have been few conclusive human trials. Probiotics and prebiotics have the potential to impact significantly on the development, progression and treatment of colorectal cancer and may have a valuable role in cancer prevention.