By James Gamble
Variations in gut bacteria could prove key in predicting the onset of colon cancer, a new study suggests.
European researchers identified differences in the gut microbiome of people who developed pre-cancerous colonic lesions, suggesting a potential connection between gut bacteria and the onset of colorectal lesions and cancers.
The findings of the large-scale study, presented at United European Gastroenterology (UEG) Week 2023 in the Danish capital of Copenhagen, offer promising new methods for the detection and prevention of colon cancer, also known as colorectal cancer – the second leading cause of all cancer-related deaths.
The study team, from the Netherlands, involved 8,202 participants and linked data from the Dutch Microbiome Project with the Dutch nationwide pathology database to identify all recorded cases of colonic biopsies from the last five decades.
Colorectal cancer poses a significant health concern across Europe, ranking as the second most prevalent cancer and the second leading cause of cancer-related deaths.
It typically develops from pre-cancerous lesions within the gut; making the removal of these lesions an effective strategy for preventing colorectal cancer.
Existing, non-invasive detection methods – such as the fecal immunochemical test – produce a high number of false positives, leading to unnecessary colonoscopies.
They analyzed the function and composition of the gut microbiomes of those who developed pre-cancerous colorectal lesions before fecal sampling undertaken in the 15 years between 2000 and 2015, as well as those who developed lesions after sampling between 2015 and 2022.
These groups were then compared with individuals with normal colonoscopy findings and the general population.
To gain a deeper insight into the gut microbiome’s role, researchers also examined specific bacterial strains and their functions within the gut by reconstructing their genomes from metagenomic data.
The researcher’s results revealed that people who developed colonic lesions after faecal sampling showed increased diversity in their gut microbiome – the community of microorganisms in their gut – in comparison with those who didn’t develop lesions.
Further to this, the composition and function of the microbiome differed amongst those with pre-existing or future lesions and also varied based on the type of legion.
Notably, bacterial species from the family of Lachnospiraceae and the genera Roseburia and Eubacterium were linked with the future development of lesions.
Dr. Ranko Gacesa, the study’s lead author from the University Medical Center Groningen in northern Holland, said his team’s results show people’s gut microbiomes could help advance early detection methods for colorectal cancer.
“While we didn’t investigate mechanisms in this study, it is known from previous research that some of the bacterial species identified may have properties that could contribute to the development of colorectal lesions,” Dr. Gacesa explained.
“A bacterium called Bacteroides fragilis, for example, is known to produce a toxin that can lead to chronic low-grade inflammation in the gut.
“Prolonged inflammation is believed to be potentially genotoxic and carcinogenic, meaning it may cause genetic damage and promote cancer.
“The connection between the gut microbiome and pre-cancerous lesions has been underexplored, leaving uncertainty about whether gut bacteria can predict the future onset of colorectal cancer.
“Our findings suggest that the microbiome could act as a valuable tool to improve existing tests, advancing early detection methods for pre-cancerous lesions and colorectal cancer.”
Produced in association with SWNS Talker