Human oral microbiome and prospective risk for pancreatic cancer: a population-based nested case-control study

TLDR

Periodontal disease and antibodies to oral pathogens have been linked to pancreatic cancer, but prospective evidence of oral microbes is lacking. This study investigates whether oral microbiota composition predicts future pancreatic cancer risk in a large nested case‑control cohort. Researchers sequenced 16S rRNA from pre‑diagnostic oral wash samples of 361 cases and 371 controls and applied logistic regression, including L1‑penalized models, to assess associations. Carriage of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans increased risk (OR 1.60 and 2.20), while higher abundance of Fusobacteria and Leptotrichia decreased risk (OR 0.94 and 0.87), with associations persisting after excluding early cases.

Abstract

A history of periodontal disease and the presence of circulating antibodies to selected oral pathogens have been associated with increased risk of pancreatic cancer; however, direct relationships of oral microbes with pancreatic cancer have not been evaluated in prospective studies. We examine the relationship of oral microbiota with subsequent risk of pancreatic cancer in a large nested case-control study.We selected 361 incident adenocarcinoma of pancreas and 371 matched controls from two prospective cohort studies, the American Cancer Society Cancer Prevention Study II and the National Cancer Institute Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. From pre-diagnostic oral wash samples, we characterised the composition of the oral microbiota using bacterial 16S ribosomal RNA (16S rRNA) gene sequencing. The associations between oral microbiota and risk of pancreatic cancer, controlling for the random effect of cohorts and other covariates, were examined using traditional and L1-penalised least absolute shrinkage and selection operator logistic regression.Carriage of oral pathogens, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, were associated with higher risk of pancreatic cancer (adjusted OR for presence vs absence=1.60 and 95% CI 1.15 to 2.22; OR=2.20 and 95% CI 1.16 to 4.18, respectively). Phylum Fusobacteria and its genus Leptotrichia were associated with decreased pancreatic cancer risk (OR per per cent increase of relative abundance=0.94 and 95% CI 0.89 to 0.99; OR=0.87 and 95% CI 0.79 to 0.95, respectively). Risks related to these phylotypes remained after exclusion of cases that developed within 2 years of sample collection, reducing the likelihood of reverse causation in this prospective study.This study provides supportive evidence that oral microbiota may play a role in the aetiology of pancreatic cancer.