Study shows how gut bacteria can reveal signs of cancer

Local medical experts have found that changes in gut bacteria can be used to detect colorectal cancer in young people.

Differences in gut microbiome, metabolites and microbial enzymes can be used as biomarkers for early and precise detection of early-onset colorectal cancer, they said.

Colorectal cancer is a common digestive cancer which usually effects the elderly. However, more young people have developed the disease in recent years.

According to the US-based National Cancer Institute, the incidence of colorectal cancer among young people is expected to double in the next 15 years. Some 20 percent of the cases will be among those less than 50 years old.

Young people who go to the hospital with symptoms have already missed the best time for early diagnosis and treatment, doctors said.

"Though colonoscopy is the most effective measure for colorectal cancer screening, the benefit of widely carrying out such checks among young people is not higher than the risk," said Dr Ma Yanlei from Shanghai Cancer Center.

"Over-diagnosis also can cause unnecessary financial cost. Colorectal cancer patients between 20 and 34 only account for 1 percent of the total patients, while the percentage is just 6.8 for patients between 35 and 49."

"So developing a better and more convenient colorectal cancer screening tool to identity young people is the key for clinical research for early-onset colorectal cancer."

Doctors focus on gut micro-organisms, an important environment determining a person's intestinal health.

Ma's team spent four years studying 549 Chinese young colorectal cancer patients, elderly colorectal cancer patients and healthy people.

It is the first such large-sample genetic research.

"The research found these young patients have a serious imbalance of gut bacteria and the low biodiversity of excrement," Ma said. "Their bacteria spectrum and metabolites are also quite different from elderly cancer patients."

Experts found early-onset colorectal cancer is associated with enriched Flavonifractor plauti, a gut bacterium, red meat intake-related bacteria, bile acid and choline metabolism.

"A model combing these biomarkers has a strong potential to be developed into a useful screening tool for young people with colorectal cancer risk," he said.

Based on the research, doctors said young people can avoid risk factors and adopt a healthy style for colorectal cancer prevention and control.

Tips include quitting smoking, avoiding fried food, reducing intake of high-fat and high-cholesterol food, increasing intake of high-fiber and high-vitamin food, doing more exercises and remaining a good mental status.

It is important to visit the doctors for stomach issues or having changes in bowel habits. Early checks and screening is crucial for colorectal cancer prevention and treatment.

The research was published by world-leading medical journal Gut.