Study: Oral bacteria linked to pancreatic cancer risk

2013 04 29 16 40 49 422 Bacteria 200

When certain bacteria are found in a patient's mouth, it may indicate an increased risk for pancreatic cancer, according to a study presented by U.S. researchers at the meeting of the American Association for Cancer Research (AACR).

The study, which was presented on April 19 in New Orleans, could allow earlier, more precise treatment of the disease, which is responsible for 40,000 deaths in the U.S. each year.

"Our study offers the first direct evidence that specific changes in the microbial mix in the mouth -- the oral microbiome -- represent a likely risk factor for pancreatic cancer along with older age, male gender, smoking, African-American race, and a family history of the disease," stated Jiyoung Ahn, PhD, an associate professor of population health and environmental medicine at the New York University School of Medicine, in a press release.

Periodontitis links

Patients with pancreatic cancer are vulnerable to periodontitis, caries, and poor oral health in general, the study authors noted. The researchers investigated links between the bacteria that causes oral disease and the subsequent development of pancreatic cancer.

“These bacterial changes in the mouth could potentially show us who is most at risk of developing pancreatic cancer.”
— Jiyoung Ahn, PhD, associate professor of population health and environmental medicine, New York University School of Medicine.

The prospective study analyzed the relationship of oral microbiota with subsequent risk of pancreatic cancer. The study compared the bacterial contents in mouthwash samples from 361 U.S. men and women who developed pancreatic cancer with samples from 371 people of similar age, gender, and ethnic origin who did not have the disease.

Both groups were part of large cancer prevention and screening studies conducted by the U.S. National Cancer Institute and the American Cancer Society. Researchers obtained mouthwash samples at the beginning of the studies, after which participants were monitored for nearly a decade to determine who developed cancer.

The bacteria Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans were associated with higher risks of pancreatic cancer, the researchers found. Patients whose oral microbiomes included P. gingivalis had an overall 59% greater risk of developing pancreatic cancer than those whose microbiomes did not contain the bacterium (95% confidence interval [CI]: 1.15-2.20). Similarly, patients whose oral microbiomes contained A. actinomycetemcomitans were at least 50% more likely overall to develop the disease (95% CI: 1.15-4.15).

Both types of bacteria have been tied in the past to periodontitis, the study authors noted.

Periodontal disease link

The American Academy of Periodontology (AAP) looked to this and other research as a way to learn about risk factors and prevention strategies.

"There is an extensive body of literature that indicates an association between periodontal disease and a number of systemic conditions. The recent AACR abstract about oral bacteria and pancreatic cancer risk is the latest contribution to this swath of research, and we hope that further study on this may unearth some insight on risk factors and possible strategies for prevention and treatment," noted Wayne Aldredge, DMD, president of the AAP, in a statement to

"These bacterial changes in the mouth could potentially show us who is most at risk of developing pancreatic cancer," stated Ahn, referring to the current study presented in New Orleans.