Oral bacteria may increase risk for pancreatic cancer

NEW ORLEANS — Two species of bacteria linked to periodontal disease may increase the risk for pancreatic cancer, according to results of a nested case–control study presented at the American Association for Cancer Research Annual Meeting.

Researchers also found presence of a specific pathogen decreased risk for pancreatic cancer.

“Previous studies have shown that indicators of poor oral health, including a history of periodontal disease and lots of missing teeth, are associated with an increased risk of pancreatic cancer,” Jiyoung Ahn, PhD, associate professor of population health and associate director of population sciences at the Laura and Isaac Perlmutter Cancer Center at NYU Langone Medical Center, said in a press release. “To test the idea that this association is driven by species of oral bacteria linked to periodontal disease, we first needed to determine whether these bacteria are even associated with pancreatic cancer risk.”

Ahn and colleagues evaluated data from 361 patients with incident pancreatic cancer and 371 matched controls enrolled in the Cancer Prevention Study II and the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial.

Researchers characterized oral microbiota using bacterial 16S rRNA gene amplification and sequencing from prediagnostic oral wash samples. When examining the association between oral microbiota and risk for pancreatic cancer, researchers controlled for random effect of cohorts and age, race, sex, smoking status, alcohol consumption, BMI and history of diabetes.

Overall, results showed a significant association between risk for pancreatic cancer and presence of oral pathogens Porphyromonas gingivalis (OR = 1.59, 95% CI, 1.15-2.2) and Aggregatibacter actinomycetemcomitans (OR = 2.19, 95%CI, 1.15-4.15).

However, greater relevant abundance of phylum Fusobacteria decreased risk for pancreatic cancer (OR = 0.92, 95% CI, 0.87-0.98).

Risks persisted even after excluding samples from people who developed pancreatic cancer within 2 years of collection of their oral wash samples.

Because the cohort was composed primarily of non-Hispanic white and healthy individuals, a lack of diversity may limit the results and make the findings inapplicable to the general population, according to the researchers.

“These data do not show a causal relationship, but they are the first steps in understanding a potential new risk factor for pancreatic cancer, which is vital if we are to develop new approaches for pancreatic cancer prevention and early detection in the future,” Ahn said. “About 1.5% of U.S. men and women will be diagnosed with pancreatic cancer at some point in their life. However, only 5% survive 5 years or more after their diagnosis. New approaches to pancreatic cancer prevention and early detection are urgently needed.” – by Nick Andrews

Reference: Fan X, et al. Abstract 4350. Presented at: American Association for Cancer Research Annual Meeting; April 16-20, 2016; New Orleans.

Disclosure : The researchers report no relevant financial disclosures.