People with pancreatic cancer could be identified quickly by examining their tongue, according to a new study.
Researchers found that differences in levels of certain bacteria living on the tongue can distinguish patients with early pancreatic cancer from healthy people.
Although disruptions to the microbiome – the microorganisms that live in and on our bodies – have already been identified in pancreatic cancer patients in other body tissues, the new study provides the first evidence of changes to the bacteria in the tongue coating.
If confirmed in larger studies, researchers say it could pave the way towards the development of new life-saving early detection or prevention tools to combat the highly aggressive disease.
Up to 10,000 people are diagnosed with pancreatic cancer in Britain each year, with less than one per cent surviving beyond 10 years.
An early diagnosis can hugely improve the chances of successful treatment.
But that poses challenges as the disease grows deep inside the body and often shows few symptoms before it has already spread.
As a result, most patients are already at an advanced stage of the disease by the time they seek medical help.
Researchers are searching for biological changes that can accurately detect early signs of pancreatic cancer, which could be developed into new screening tests.
A current area of discussion is the potential role of the microbiome in the development of cancer, with previous studies identifying dramatic disruptions to bacteria in saliva, intestinal and faecal samples collected from pancreatic cancer patients compared to healthy people.
In the first study to characterise the tongue coat microbiome of people with pancreatic cancer, a team of researchers recruited a group of 30 patients with early-stage disease and 25 healthy people.
The participants were all between 45 and 65, had no other diseases or oral health problems and had not taken any antibiotics or other drugs in the three months before the study.
The team used sophisticated gene sequencing technology to examine the microbiome diversity of tongue coat samples, finding that pancreatic cancer patients were colonised by “remarkably different” tongue coating microbiomes compared to healthy people.
Study lead author Professor Li Lanjuan, of Zhenjiang University in China, said: “Although further confirmatory studies are needed, our results add to the growing evidence of an association between disruptions to the microbiome and pancreatic cancer.”
She said the abundance of four types of bacteria – low levels of Haemophilus and Porphyromonas and high levels of Leptotrichia and Fusobacterium – could distinguish pancreatic cancer patients from healthy individuals.
Prof Lanjuan added: “If an association between the discriminatory bacteria and pancreatic cancer is confirmed in larger studies, this could potentially lead to the development of new microbiome-based early diagnostic or preventive tools for the disease.”
The researchers believe that the immune system is the most likely link between any confirmed shifts in the microbiome with pancreatic cancer – for example, disease development in the pancreas may influence the immune response in ways that favour the growth of certain bacteria – or vice versa.
If proven, thy say it could set the stage for the development of new treatments involving antibiotics or immunotherapies – or potentially even probiotics that can help prevent pancreatic cancer in high-risk patients in the future.
The findings were published in the Journal of Oral Microbiology.