Gut microbiome changes associated with precancerous colon polyps: Study

Researchers at Mass General Brigham have connected specific types of gut bacteria to the growth of precancerous colon polyps in a recent study.

The findings of the study were published in Cell Host & Microbe.

“Researchers have done a lot of work to understand the relationship between the gut microbiome and cancer. But this new study is about understanding the microbiome’s influence on precancerous polyps,” said co-corresponding author Daniel C. Chung, MD, medical co-director of the Center for Cancer Risk Assessment at the Mass General Cancer Center and a faculty member of the Gastroenterology Division. “Through the microbiome, we potentially have an opportunity to intervene and prevent colorectal cancer from forming.”

The incidence of colorectal cancer is increasing among young individuals, and it is the second most common cause of cancer-related death in the United States. A precancerous polyp is the primary cause of almost all colorectal malignancies. Stopping growth at the polyp stage is one of the best strategies to lower the occurrence of colorectal cancer.

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 think these environmental influences could promote polyp growth in one of two ways. Either they change the gut microbiome directly in a way that encourages polyp growth, or they promote polyp growth which in turn influences the gut microbiome by directly affecting the cells lining the intestines.

Earlier, smaller studies trying to link the gut microbiome to polyps have not found a consistent pattern, though they didn’t look at these two types of polyps specifically.