Poor oral health linked to higher risk of pancreatic cancer

Pancreatic cancer is hard to catch early and often turns deadly. According to federal statistics, the overall five-year relative survival across all stages is close to 13 percent, and more than half of cases are found after the disease has spread.

Scientists at NYU Langone Health report a large analysis that connects microbes in saliva to later risk for this cancer.

The team followed 122,000 adults and found that a set of bacteria and fungi in the mouth was tied to a more than threefold higher chance of developing pancreatic cancer.

Mouth microbes matter

Dr. Yixuan Meng, at NYU Grossman School of Medicine, led the work in collaboration with the Perlmutter Cancer Center (PCC).

The experts focused on the oral microbiome, the mix of bacteria and fungi that live in the mouth and shift with diet, hygiene, illness, and medications.

Links between oral health and pancreatic cancer have surfaced before.

Earlier prospective research connected certain oral bacteria to later pancreatic cancer in smaller samples, but species level detail and fungal data were limited.

Attention is turning to fungi as well as bacteria. Species of Candida, a common yeast, can thrive in the mouth under certain conditions, and scientists are testing whether these organisms signal risk far from the teeth and gums.

The new report expands the picture with far more people and deeper microbial profiling. It also looks at how a combined set of species may matter more than any single microbe.

Linking oral health and cancer risk

The analysis drew on two national cohorts that track health over many years. In a trial conducted by the National Cancer Institute, participants in the control arm provided an oral wash sample that has been linked to later cancer outcomes.

The companion cohort run by the American Cancer Society (ACS) began in the early 1990s and follows tens of thousands of men and women across the United States with regular updates on health and lifestyle.

Together, these resources allow researchers to compare people who later develop cancer with similar participants who remain cancer free.

Saliva and mouthwash rinse samples preserve DNA from oral microbes.

Mouthwash samples perform similarly to saliva for microbiome analysis, which makes large studies practical because a simple rinse can capture usable material.

The NYU team used whole genome shotgun sequencing to profile bacterial DNA and internal transcribed spacer sequencing to profile fungal DNA.

These techniques identify microbes at the species level and quantify their relative abundance with much finer resolution than older methods.

Key findings of the study

The researchers compared 445 people who developed pancreatic cancer with 445 matched controls who did not. Twenty-seven oral species, considered together, were linked to a more than threefold increase in risk.

Three bacterial pathogens tied to periodontal disease stood out for higher risk. Porphyromonas gingivalis, Eubacterium nodatum, and Parvimonas micra showed positive associations in models that adjusted for age, sex, race, and smoking.

Fungal signals appeared as well. The genus Candida was associated with increased risk, pointing to the value of including the mouth’s mycobiome rather than focusing on bacteria alone.

Estimating pancreatic cancer risk

The investigators built a microbial risk score (MRS) that adds up contributions from 27 bacterial and fungal species.

A higher score correlated with a higher chance of later diagnosis, suggesting a path to identify people who might benefit from closer follow up.

“By profiling bacterial and fungal populations in the mouth, oncologists may be able to flag those most in need of pancreatic cancer screening,” said Jiyoung Ahn, associate director for population sciences at Perlmutter Cancer Center. This approach would be noninvasive and could be repeated over time.

There is no standard screening test for average risk adults, and most cases are found after spread. That makes early risk markers valuable to study, especially when they come from a quick rinse rather than a scan or a biopsy.

An observational design cannot prove cause. The results point to associations that will need confirmation and experiments to test mechanisms, including how oral communities might influence inflammation, immunity, or the pancreatic tissue environment.

Oral health and cancer prevention

“It is clearer than ever that brushing and flossing your teeth may not only help prevent periodontal disease but may also protect against cancer,” said Dr. Richard Hayes, a professor in the Department of Population Health at NYU Grossman School of Medicine.

Good daily care supports gum health and may keep harmful pathogens in check. The study does not suggest self-testing or treatment based on a single microbe.

Patterns mattered more than any one species, and clinical use would require careful validation and thresholds that balance benefits and harms.

Diverse microbes share the mouth, and they change with smoking, diet, antibiotics, and illness. Keeping regular dental visits, managing chronic conditions, and avoiding tobacco remain sensible steps while scientists refine risk tools.

Future studies will examine whether oral viruses contribute to pancreatic cancer, how microbial communities in the mouth shift before and after diagnosis, and whether these changes influence survival outcomes.

Profiling both bacterial and fungal populations in the mouth also raises new possibilities for prevention strategies and for communicating risk to people with a family history or other factors that increase susceptibility.

The study is published in the journal JAMA Oncology.

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