By Danielle 
A new cohort study of 122,000 adults reports that specific oral bacteria — and the fungal genus Candida — were linked with a higher risk of developing pancreatic cancer years later.
Published Sept. 18 in JAMA Oncology by researchers at NYU Grossman School of Medicine and collaborators, the nested case–control analysis identified 445 people who developed pancreatic cancer during a median follow-up of 8.8 years and matched them 1:1 with 445 cancer-free controls by cohort, age band, sex, race and ethnicity, and time since oral sample collection. Roughly 0.36 per cent of the overall cohort developed pancreatic cancer during follow-up.
The findings
Using whole-genome shotgun sequencing (bacteria) and internal transcribed spacer sequencing (fungi), the team found three periodontal pathogens — Porphyromonas gingivalis, Eubacterium nodatum and Parvimonas micra — were associated with increased risk.
A microbiome-wide scan also flagged additional bacteria tied to higher or lower risk, and the fungal genus Candida was associated with increased risk.
A composite microbial risk score based on 27 oral species was linked to a more than threefold increase in pancreatic cancer risk per one-standard deviation increase (adjusted OR 3.44; 95% CI, 2.63–4.51).
Microbial profiles as biomarkers
The authors conclude that oral microbial profiles may serve as non-invasive biomarkers to identify people at higher risk, while cautioning that the observational design does not prove causation.
Pancreatic cancer has one of the lowest survival rates, in part because its symptoms can mimic other ailments.
Canadian and U.S. context
- Canada: Pancreatic cancer is projected to be the third leading cause of cancer death in 2024, with an estimated 6,100 deaths.
- United States: An estimated 107,988 people were living with pancreatic cancer in 2022; lifetime risk is about 1.6 per cent, based on 2018–2021 data (excluding 2020).