The different types of bacteria living on the tongue can distinguish patients with early pancreatic cancers from healthy individuals, according to results from a new study published in the Journal of Oral Microbiology.
This is the first evidence that suggests changes to the bacteria in the tongue could be an early indicator of pancreatic cancer. If confirmed in larger studies, this could pave the way towards the development of new life-saving early detection or prevention tools for this highly aggressive disease.
Early diagnosis of pancreatic cancer can greatly improve chances of successful treatment - but this poses challenges for this disease as it grows deep inside the body and often shows few symptoms before it has already spread. As a result, most patients already have advanced disease by the time they seek medical help.
With researchers searching for biological changes that can accurately detect early signs of pancreatic cancer, a current hot topic is the potential role of the microbiome in the development of cancer. Previous studies have already seen dramatic disruptions to bacteria in saliva, intestinal and faecal samples collected from pancreatic cancer patients compared to healthy individuals.
In the first study to characterise the tongue coat microbiome of patients with pancreatic cancer, a team of researchers recruited a group of 30 patients with early-stage disease (diagnosed with a tumour positioned in the 'head' area of the pancreas) and a similar group of 25 healthy people.
Participants were all between 45 and 65 years in age, had no other diseases or oral health problems and had not taken any antibiotics or other drugs for the three months before the study.
The research team used gene sequencing technologies to examine the microbiome diversity of tongue coat samples and found that pancreatic cancer patients were colonised by remarkably different tongue coating microbiomes compared to healthy individuals.
Speaking about it, lead author Lanjuan Li 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."
Notably, 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.
The research team hypothesises that the immune system is most likely a link between any confirmed shifts in the microbiome with pancreatic cancer. They theorise that disease development in the pancreas may influence the immune response in ways that favour the growth of certain bacteria - or vice versa. If proven, this could set the stage for the development of new treatment strategies involving antibiotics or immunotherapies - or potentially even probiotics that can help prevent pancreatic cancer in high-risk patients in the future.