The Gut Microbiome Differs in Characteristic Ways in Patients with Precancerous Colon Polyps

The gut microbiome changes with age, the relative abundance of microbial populations shifting in ways that appear connected to chronic inflammation and dysfunction of the intestinal epithelium and intestinal barrier function. Cancer of the colon is an important cause of human mortality, and there is some hope that finding ways to prevent or reverse gut microbiome aging, such as via fecal microbiota transplant from young individuals, will go some way to minimizing colon cancer incidence.

Colorectal cancer is the second leading cause of cancer-related death in the U.S., and rates of colorectal cancer are rising among young adults. Nearly all colorectal cancers arise from a precancerous polyp. One of the best ways to reduce the incidence of colorectal cancer is to stop the growth at the polyp stage. There's more than one way for a polyp to develop. The two main types of polyps are tubular adenomas and sessile serrated polyps. Risk factors for colorectal cancer and polyps include lifestyle factors like being overweight or obese, low physical activity levels, a diet high in red and processed meats, smoking, and alcohol use. These factors also influence the bacteria that live in our intestines, collectively known as the gut microbiome.

Researchers took data from 1,200 people getting routine screening colonoscopies. They gathered information on their health, diet, medications, and lifestyle, as well as analyzed stool samples to determine the bacterial makeup of their gut microbiome. he new research is the biggest study from an extensive collaborative research program, the GI Disease and Endoscopy Registry (GIDER). This registry remains active and ongoing data collection will enable longitudinal follow-up.

The new study is the largest of its kind and analyzed the differences in the gut microbial signature of people without colon polyps, with tubular adenomas, or with sessile serrated adenomas. They also correlated this data with the patient's health and family histories. Bacterial signatures clustered into three groups based on the type and presence of polyps in the colon. Nineteen bacterial species were significantly different in patients with tubular adenomas than in other populations. In patients with sessile serrated adenomas, eight species were significantly different. "The hope is that by changing specific aspects of the diet or the microbiome, we can alter the natural history of these polyps. Interventions to prevent polyp formation or alter their growth patterns may ultimately prevent colorectal cancer."