Study Links Bad Oral Health to Risks of Oesophageal Cancer
The toothbrush a crusader in fight against oral diseases?
Oral microbes have been linked to periodontal disease as well as to head and neck cancer. As such, researchers led by New York University School of Medicine’s Jiyoung Ahn examined whether they were also associated with the development of esophageal cancer, the eighth most common cancer.
“Our study indicates that learning more about the role of oral microbiota may potentially lead to strategies to prevent esophageal cancer, or at least to identify it at earlier stages. Our study brings us much closer to identifying the underlying causes of these cancers because we now know that at least in some cases disease appears consistently linked to the presence of specific bacteria in the upper digestive tract,” says study senior investigator and epidemiologist Jiyoung Ahn, Ph.D. “Conversely, we have more evidence that the absence or loss of other bacteria in the mouth may lead to these cancers, or to gut diseases that trigger these cancers.”
The mouth’s overall bacterial makeup, which can be changed by smoking, heavy drinking, diet, and gum disease or gastric reflux, has long been thought to influence risk of esophageal adenocarcinoma or squamous cell carcinoma, according to the scientists.
The team collected oral wash samples from 122,000 participants in two large health studies: the National Cancer Institute Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial and the American Cancer Society Cancer Prevention Study II Nutrition cohort.
In 10 years of follow-up, 106 participants developed esophageal cancer. In a prospective case-control study, the researchers extracted DNA and sequenced oral wash samples, allowing researchers to compare the oral microbiomes of the esophageal cancer cases and the cancer-free cases.
Certain bacteria types were associated with higher risk of esophageal cancer. For example, higher levels of the Tannerella forsythia bacteria were associated with a 21 percent increased risk of EAC. The bacteria Porphyromonas gingivalis was associated with a higher risk of ESCC. Both species of bacteria are linked with common gum disease, Ahn noted.
The study showed that a few types of oral bacteria were associated with lower risk of esophageal cancer. For example, the Neisseria bacteria was associated with lower risk of EAC.
Ahn said the finding on Neisseria indicates that certain bacteria may have a protective effect, and future research could potentially examine whether these bacteria could play a role in preventing esophageal cancer.
Ahn added that the study confirms that good oral health, including regular tooth brushing and dental visits, is an important way to guard against periodontal disease and the growing list of health conditions associated with it.
