A major new study has found that oral bacteria associated with gum disease could increase the risk of developing pancreatic cancer by more than three times.

Researchers analysed data from over 122,000 adults who provided saliva samples and were followed for nearly a decade. They discovered that people carrying certain microbes in their mouths were far more likely to develop pancreatic cancer, one of the deadliest forms of the disease.

Key Results

The study identified several oral bacteria and fungi that appeared to influence cancer risk:

• Periodontal pathogens such as Porphyromonas gingivalis, Eubacterium nodatum and Parvimonas micra were strongly linked to increased risk.
• The common fungal genus Candida was also associated with higher cancer incidence.
• Overall, a “microbial risk score” based on 24 microbial species predicted a 3.44-fold higher risk of pancreatic cancer for each incremental increase.

Conversely, some oral microbes appeared protective, reducing the likelihood of cancer.

Why Oral Health Matters

Scientists have long suspected a link between gum disease and pancreatic cancer, but this is the first large-scale study to pinpoint specific microbial culprits. One theory is that harmful bacteria travel from the mouth to the pancreas, triggering chronic inflammation or producing toxins that promote tumour growth.

Dr. Jiyoung Ahn of NYU Grossman School of Medicine, one of the study’s lead authors, noted:

“Our findings provide strong evidence that oral health, particularly the bacteria living in our mouths, may play a role in cancer risk. This could open up new ways to screen people using saliva samples.”

Potential for Screening

Because saliva is easy to collect, researchers believe oral microbiome profiling might one day be used to identify individuals at higher risk of pancreatic cancer. This could enable earlier screening or monitoring in people with a family history or other risk factors.

However, experts warn the findings are associative, not causal. Further research is needed to confirm whether these microbes directly drive cancer development, or whether they are simply markers of underlying disease processes.

The Bigger Picture

Pancreatic cancer is often diagnosed late and carries a poor prognosis, with fewer than one in 10 patients surviving five years after diagnosis. Any breakthrough that allows earlier detection could save lives.

For now, experts recommend maintaining good oral hygiene, stopping smoking, and controlling other known risk factors such as obesity and diabetes.

References

• Ahn, J., Vogtmann, E., Provatopoulou, X., et al. (2025) Oral microbiota and risk for pancreatic cancer: findings from a large prospective cohort study. Journal of the National Cancer Institute, [online] Available at: https://nyulangone.org/news/oral-microbes-linked-increased-risk-pancreatic-cancer [Accessed 2 October 2025].
• The ASCO Post (2025) Oral microbiota and risk for pancreatic cancer. [online] Available at: https://ascopost.com/news/september-2025/oral-microbiota-and-risk-for-pancreatic-cancer/ [Accessed 2 October 2025].
• AMA (2025) Can the oral microbiome help predict pancreatic cancer risk? American Medical Association. [online] Available at: https://www.ama-assn.org/public-health/chronic-diseases/can-oral-microbiome-help-predict-pancreatic-cancer-risk [Accessed 2 October 2025].
• Gastroenterology Advisor (2025) Oral bacteria and fungi linked to pancreatic cancer. [online] Available at: https://www.gastroenterologyadvisor.com/news/oral-bacteria-fungi-linked-to-increased-risk-for-pancreatic-cancer/ [Accessed 2 October 2025].
• Naples Periodontist (n.d.) Gum disease and pancreatic cancer. [online] Available at: https://www.naplesperiodontist.com/Gum-Disease/Gum-Disease-and-Pancreatic-Cancer [Accessed 2 October 2025].