Inside the Gut Revolution in Liver Cancer Care

Intro : From tumour growth to treatment response, experts believe gut bacteria may play a far bigger role in liver cancer than previously understood

Byline: Swati Sharma

For decades, cancer research focused on genes, tumours, and scans. Now, scientists are increasingly looking deep inside the human gut. According to D. Nageshwar Reddy, gastroenterologist and founder of the Asian Institute of Gastroenterology, the microbiome, the ecosystem of bacteria, fungi, and viruses living in the digestive tract, may become one of the most important frontiers in liver cancer research.

New studies on hepatocellular carcinoma (HCC), the most common form of liver cancer, suggest gut bacteria may influence cancer growth, immunity, and treatment response. With liver cancer cases rising globally due to hepatitis, alcohol use, obesity, diabetes, and fatty liver disease, experts believe microbiome science could reshape precision oncology.

Invisible universe inside the human body

According to Dr Reddy, the human gut contains trillions of microorganisms that actively influence digestion, immunity, metabolism, and neurological signalling. “For decades, scientists could study only a small fraction of gut microbes because most could not be grown in laboratories,” he says. “Advanced technologies such as metagenomics and 16S rRNA sequencing have now revealed the enormous complexity of the microbiome and its impact on human health.”

According to him, scientists once considered much of the microbiome “microbial dark matter” because it remained invisible to traditional laboratory techniques.“Today, advanced molecular tools are uncovering how deeply these microbes influence systemic diseases, including cancer,” he adds.

Understanding the gut-liver axis

Dr Reddy explains that the microbiome has become central to liver cancer research because of the “gut-liver axis,” the direct biochemical connection between the intestine and liver through portal vein circulation.

“The liver receives nearly 70 percent of its blood supply directly from the gut, making it continuously exposed to microbial products, toxins, and inflammatory signals,” he says. When gut bacteria become disrupted, a condition called dysbiosis, harmful bacterial products can travel directly to the liver, triggering chronic inflammation and long-term cellular damage.

According to Venkata Sampath V, consultant medical oncologist at Apollo Hospitals, studies have already demonstrated measurable microbial shifts as liver disease progresses toward hepatocellular carcinoma. “Some bacterial species may directly damage liver cell DNA, while others weaken the immune system’s ability to recognise and destroy cancer cells,” Dr Sampath explains. Researchers have identified bacteria within liver tumours that may promote tumour growth and help cancer cells evade the immune system.

A new era of cancer detection

Today, liver cancer diagnosis largely depends on imaging scans and blood tests such as AFP and PIVKA-II. However, Dr Reddy says microbiome science could eventually transform early detection strategies. “Specific microbial signatures found in stool, blood, or tissue samples may help identify high-risk patients before tumours become visible on imaging,” he says. Such discoveries complement conventional diagnostic methods and improve early detection, one of the biggest challenges in liver cancer care.

Can gut bacteria improve cancer treatment?

According to Dr Sampath, one promising area is faecal microbiota transplantation (FMT), where healthy donor microbes are introduced into a patient’s gut to restore microbial balance. “Scientists believe this approach could potentially enhance the effectiveness of immunotherapy in liver cancer patients,” he says. Clinical studies such as the FLORA trial are now exploring whether combining microbiome interventions with standard immunotherapy could improve treatment outcomes in unresectable HCC.

Promise of bacteriophage therapy

Another rapidly evolving area is bacteriophage therapy. According to Dr Sampath, bacteriophages, or phages, are naturally occurring viruses that infect and destroy specific bacteria. “Phages act with remarkable precision and may help eliminate bacteria linked to tumour growth without disturbing beneficial microbes,” he says.

Future of precision oncology

Experts caution that many questions remain unanswered. Dr Reddy says: “The microbiome is steadily moving from laboratory research into clinical relevance,” he says. “In the future, microbes inside the human body may become as important as scans, biopsies, and blood tests in understanding cancer itself.”

Key liver cancer risk factors

· Hepatitis B and C infections

· Alcohol-related liver disease

· Obesity

· Diabetes

· Fatty liver disease

· Chronic liver inflammation

What is dysbiosis?

Dysbiosis refers to an imbalance in gut bacteria. Experts believe this disrupted microbial environment may trigger chronic inflammation, weaken immunity, and create conditions favourable for liver cancer progression.

Emerging future therapies

· Faecal Microbiota Transplantation (FMT): Introducing healthy donor microbes into the gut to restore microbial balance.

· Bacteriophage Therapy: Using naturally occurring viruses called phages to selectively destroy harmful bacteria without affecting beneficial microbes.