Are Some Oral Pathogens More Common in Patients With Esophageal Cancer?

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In a new study published by Kawasaki et al in the journal Cancer, researchers reported that certain oral pathogens are more prevalent in patients with esophageal cancer, and pointed out this information may be used as a novel diagnostic tool.

The oral cavity is a rich source of microbial diversity, with more than 700 bacterial species. The vast majority of these species are harmless, but a select few cause conditions such as gingivitis, periodontitis, and abscesses. While the role of these pathogens in periodontal disease is well characterized, more recent studies have hinted at involvement in gastric and esophageal cancers.

In this new study, researchers characterized the oral bacterial communities of patients with esophageal cancer to look for patterns associated with cancer risk and lay foundations for further exploration of the role of oral pathogens in disease.

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“Esophageal cancer is the sixth most deadly cancer worldwide and is often not detected until an advanced stage, meaning that the prognosis is generally poor,” said lead study author Machiko Kawasaki, DDS, of Tokyo Medical and Dental University. “Complicating matters, the two main subtypes of esophageal cancer have different risk factors, presentations, and incidence rates in different populations. A better understanding of the causes of esophageal cancer could therefore help with early detection.”

Study Findings

To explore the characteristics of the oral bacterial community in patients with esophageal cancer, researchers collected dental plaque and saliva samples from 61 patients with cancer and 62 matched individuals without cancer. Using real-time polymerase chain reaction, the researchers screened DNA extracted from the plaque and saliva samples to determine the abundance of seven common periodontal pathogens—Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Treponema denticola, and Streptococcus anginosus—in the bacterial population as a whole.

“Interestingly, five of the seven pathogens were more abundant in dental plaque from [patients with] cancer than that from the healthy controls, with the detection rate of six of the seven pathogens was significantly higher in the patients with cancer,” explained senior author Satoshi Miyake, MD, PhD, also of Tokyo Medical and Dental University. “On the other hand, only two of the seven pathogens, A actinomycetemcomitans and S anginosus, were more abundant in saliva from [patients with] cancer.”

Overall, the researchers determined that an increased prevalence of S anginosus and T forsythia in dental plaque and A actinomycetemcomitans in saliva—as well as alcohol consumption—were associated with a high risk of esophageal cancer.

The study findings are an indication of the diagnostic potential of oral bacteria in esophageal cancer, and could form the basis of future screening methods.

Disclosure: For full disclosures of the study authors, visit

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.