Colorectal cancer and stomach cancer are two gastrointestinal cancers whose origins are most probably influenced by the intestinal microbiota.
Colorectal cancer, the importance of environmental factors
With 694,000 deaths per year around the world, colorectal cancer is the 2nd most deadly cancer. Genetic factors are a significant but minority cause of gastrointestinal cancer, which is most heavily attributed to environmental factors such as sedentary lifestyle, obesity, and, in particular unbalanced diet, which causes intestinal dysbiosis. Furthermore, the hypothesis of an imbalance between harmful and beneficial bacterial species with regard to this cancer is more than likely.
Colorectal cancer doesn’t show any symptoms for a long time, then manifests by persistent or sudden problems with intestinal transit: constipation, diarrhea, the pressing need to go, etc.
Examining the stool for blood and colonoscopy are the two primary methods for detecting colorectal cancer.
Surgery forms the basis of treatment via the removal of part of the colon, sometimes supplemented with chemotherapy or radiation therapy.
Bacteria responsible in 80% of stomach cancers
Although various risk factors have been identified (smoking, diet, family history, genetic predisposition), the primary cause of stomach cancer is Helicobacter pylori a pathogenic bacteria that causes chronic gastritis.
The symptoms are not very specific: stomach pain, repeated nausea and vomiting, and a change in general state. Only endoscopy of the stomach and esophagus can confirm the diagnosis.
Surgery is the reference treatment for localized tumors, with partial or total removal of the stomach. For locally advanced forms, physicians also add chemotherapy.
Restoring the microbiota, therapy of the future?
Since the existence of a connection between bacteria and gastrointestinal cancers seems more than likely, manipulating the microbiota with probiotics and prebiotics is being studied as a potential therapeutic treatment.